FR Vol 13 Geology

INVESTIGATIONS FOR UPDATING THE GROUNDWATER MATHEMATICAL MODEL(S)

OF THE SAQ AND OVERLYING AQUIFERS

GEOLOGY

VOLUME 13

Abunayyan Trading Corporation Rabi’I 1429 H BRGM Geosciences for a sustainable Earth Mach 2008 G

Investigations for Updating the Groundwater Mathematical Model(s) Volume 13 of the Saq and Overlying Aquifers Geology

Ministry of Water and Electricity – Kingdom of Saudi Arabia I

Note

The present document is part of the Final Report of the study entitled “Updating of groundwater mathematical model(s) of the Saq and overlying aquifers”.

The Final Report is composed of the following thirteen (13) volumes:

Volume 1 Main Report

Volume 2 Groundwater Management

Volume 3 Groundwater Mathematical Modelling

Volume 4 Data Management

Volume 5 Domestic and Industrial Water Demand

Volume 6 Irrigation Water Abstraction

Volume 7 Hydrology and Groundwater Recharge

Volume 8 Groundwater Quality

Volume 9 Hydrogeology

Volume 10 Water Point Inventory

Volume 11 Pumping Tests

Volume 12 Geophysical Logging

Volume 13 Geology

Executive Summary

The present document is Volume 13.

Plates are grouped in the second part of the Volume


Ministry of Water and Electricity – Kingdom of Saudi Arabia I

Contents

1. Introduction 1 1.1. PREVIOUS WORK ...................................................................................................................1 1.2. GENERAL METHODOLOGY.......................................................................................................1

2. Lithostratigraphy and hydrostratigraphy 3 2.1. LITHOSTRATIGRAPHIC UNITS...................................................................................................3 2.2. PREVIOUS SAQ HYDROSTRATIGRAPHY....................................................................................4 2.3. AQUIFER SYSTEMS.................................................................................................................5

3. Structure 15 3.1. SCHEMATIC CROSS SECTION OF THE NAFUD BASIN ...............................................................15 3.2. VARIATIONS IN LITHOSTRATIGRAPHY AND HYDROSTRATIGRAPHY ...........................................15 3.3. ROLE OF THE MAIN UNCONFORMITY SURFACES .....................................................................16 3.4. FAULTS ...............................................................................................................................17

3.4.1. The Wadi Sirhan Graben...............................................................................................17 3.4.2. Other faults....................................................................................................................19 3.4.3. Paleohighs.....................................................................................................................20

4. Data sources for the model 21 4.1. SURFACE DATA FROM BRGM BACKGROUND SOURCES..........................................................21 4.2. PUBLISHED DATA .................................................................................................................21

4.2.1. Database queries ..........................................................................................................21 4.2.2. Base document: Saq project, geological setting of the project area..............................21 4.2.3. Structure, facies, paleogeography.................................................................................21

4.3. BOREHOLES ........................................................................................................................22 4.3.1. Saq 1 .............................................................................................................................22 4.3.2. Professional papers.......................................................................................................22

5. Geological Modelling 23 5.1. METHODOLOGY ...................................................................................................................23 5.2. THE 3D MODEL ....................................................................................................................25

5.2.1. Model extent..................................................................................................................25 5.2.2. Fault blocks ...................................................................................................................25 5.2.3. Horizons modelled.........................................................................................................25 5.2.4. Results ..........................................................................................................................28 5.2.5. Model contribution to understanding of the structure ....................................................34

6. Conclusions 37 6.1. IMPLICATIONS FOR FLOW MODELLING....................................................................................37 6.2. EXPORT TO THE FLOW MODEL ..............................................................................................37


Ministry of Water and Electricity – Kingdom of Saudi Arabia II

List of figures

Figure 1. Seismic interpretation of glacial paleovalleys in the Ha’il area (McGillivray and Al-Husseini, 1992; map from Aoudey and Al-Hajri, 1994) ................................................................................................ 6

Figure 2. Extent of the Raan Member in outcrop in the Tabuk area (BRGM mapping) ....................................... 7 Figure 3. Extent of the Raan Member in outcrop in the Qasim area (BRGM mapping)....................................... 8 Figure 4. Synthetic section of the Jauf Formation in northwestern Arabia (Boucot et al., 1989) ......................... 9 Figure 5. Paleogeographic domains of the Jauf Formation (Konert et al., 2001) .............................................. 10 Figure 6. The Berwath and Unayzah formations in well ST-8 (Al-Husseini, 2004) ............................................ 12 Figure 7. Geographic extent of the Unayzah Formation in subsurface (Konert et al., 2001)............................ 13 Figure 8. Schematic SW-NE cross section of the Nafud basin (project area) - Aoudeh and Al-Hajri, 1994

[location of cross section shown on Plate 2 (Vol 13, Part 2)]. .......................................................... 15 Figure 9. Subcrop map below the pre-Hercynian unconformity (Konert et al., 2001) ........................................ 16 Figure 10. Topographic map of the Wadi Sirhan valley ..................................................................................... 18 Figure 11. N-S section (AB) in the NW of the study area (Jordan) across the Wadi Sirhan (Azraq) Graben

(Konert et al., 2001) .......................................................................................................................... 19 Figure 12. Field of N150 faults in the Tayma-Tabuk area (BRGM-DMMR 1:250,000-scale mapping) ............. 20 Figure 13. Georeferenced and rectified map of the basement structure (structure after Konert et al., 2001) ... 24 Figure 14. Fault blocks ....................................................................................................................................... 25 Figure 15. Infra-Cambrian basins (in Sharland et al., 2001, adapted from Dyer and Al-Husseini, 1991).......... 27 Figure 16. Structure of the top of basement, view from the SE (colour zone = 1,000 m) .................................. 29 Figure 17. North-south cross section (Ha’il area, x=400,000m): IC, Siq, Burj, Saq. .......................................... 29 Figure 18. Structure of the base of Qusaiba Shale Member (Qalibah Formation)............................................. 30 Figure 19. Thickness of the Qusaiba Shale Member (Qalibah Formation) ........................................................ 31 Figure 20. Pre-Hercynian subcrop underneath the pre-Unayzah unconformity (PUU)...................................... 32 Figure 21. Onlap of the pre-Hercynian formations by the marine Permian Khuff Fm. (in blue) ......................... 32 Figure 22. Completed model with Neogene sand sheets, sand dunes and Harrats.......................................... 34

List of tables

Table 1. Lithostratigraphy within the project area................................................................................................. 3 Table 2. Aquifer systems considered in the project area ..................................................................................... 5


Ministry of Water and Electricity – Kingdom of Saudi Arabia III

List of plates

(included in Volume 13 - Part 2)

Plate 1 - Location Map

Plate 2 - Location of the cross sections presented in Volume 13

Plate 3 - Digital outcrop map

Plate 4 - North-South cross section at x = 505,000 through the aquifer units

Plate 5 - Truncation of the lower Paleozoic, Saq disconnected in the graben (y=800,000, view from N)

Plate 6 - N-S cross section at x = 300,000, of the Mesozoic-Cainozoic wedge (view from W)

Plate 7 - Top elevation of the Harrats formation

Plate 8 - Top elevation of the sand-dunes formation

Plate 9 - Top elevation of the Eocene-Maastrichtian complex

Plate 10 - Top elevation of the early-mid-Cretaceous complex

Plate 11 - Top elevation of the Hith-Gotnia Formation

Plate 12 - Top elevation of the Trias-Jurassic complex

Plate 13 - Top elevation of the STQ complex (Secondary-Tertiary-Quaternary complex)

Plate 14 - Top elevation of the Sudair Shale

Plate 15 - Top elevation of the Khuff Formation

Plate 16 - Top elevation of the Ash Shiqqah Member (Khuff Formation)

Plate 17 - Top elevation of the Unayzah Formation

Plate 18 - Top elevation of the Berwath Formation

Plate 19 - Top elevation of the Jubah Formation

Plate 20 - Top elevation of the Jauf Formation

Plate 21 - Top elevation of the Tawil Formation

Plate 22 - Top elevation of the Sharawra Member (Qalibah Formation)

Plate 23 - Top elevation of the Qusaïba Shale Member (Qalibah Formation)

Plate 24 - Top elevation of the Quwara Member - Sarah Formation unit

Plate 25 - Top elevation of the Raan Member (Qasim Formation)

Plate 26 - Top elevation of the Kahfah Member (Qasim Formation)

Plate 27 - Top elevation of the Hanadir Member (Qasim Formation)

Plate 28 - Top elevation of the Saq Sandstone

Plate 29 - Bottom elevation of the Saq Sandstone

Plate 30 - Thickness of the Harrats formation

Plate 31 - Thickness of the sand-dunes formation

Plate 32 - Thickness of the Eocene-Maastrichtian complex

Plate 33 - Thickness of the early-mid-Cretaceous complex

Plate 34 - Thickness of the Hith-Gotnia complex

Plate 35 - Thickness of the Trias-Jurassic complex


Ministry of Water and Electricity – Kingdom of Saudi Arabia IV

Plate 36 - Thickness of the STQ complex (Secondary-Tertiary-Quaternary complex)

Plate 37 - Thickness of the Sudair Shale

Plate 38 - Thickness of the Khuff Formation

Plate 39 - Thickness of the Ash Shiqqah Member (Khuff Formation)

Plate 40 - Thickness of the Unayzah Formation

Plate 41 - Thickness of the Berwath Formation

Plate 42 - Thickness of the Jubah Formation

Plate 43 - Thickness of the Jauf Formation

Plate 44 - Thickness of the Tawil Formation

Plate 45 - Thickness of the Sharawra Member (Qalibah Formation)

Plate 46 - Thickness of the Qusaïba Shale Member (Qalibah Formation)

Plate 47 - Thickness of the Quwara Member - Sarah Formation unit

Plate 48 - Thickness of the Raan Member (Qasim Formation)

Plate 49 - Thickness of the Kahfah Member (Qasim Formation)

Plate 50 - Thickness of the Hanadir Member (Qasim Formation)

Plate 51 - Thickness of the Saq aquifer

Plate 52 - Depth to top of the Eocene-Maastrichtian complex

Plate 53 - Depth to top of the early-mid-Cretaceous- complex

Plate 54 - Depth to top of the Hith-Gotnia Formation

Plate 55 - Depth to top of the Trias-Jurassic complex

Plate 56 - Depth to top of the Sudair Shale

Plate 57 - Depth to top of the Khuff Formation

Plate 58 - Depth to top of the Ash Shiqqah Member (Khuff Formation)

Plate 59 - Depth to top of the Unayzah Formation

Plate 60 - Depth to top of the Berwath Formation

Plate 61 - Depth to top of the Jubah Formation

Plate 62 - Depth to top of the Jauf Formation

Plate 63 - Depth to top of the Tawil Formation

Plate 64 - Depth to top of the Sharawra Member (Qalibah Formation)

Plate 65 - Depth to top of the Qusaïba Shale Member (Qalibah Formation)

Plate 66 - Depth to top of the Quwara Member - Sarah Formation unit

Plate 67 - Depth to top of the Raan Member (Qasim Formation)

Plate 68 - Depth to top of the Kahfah Member (Qasim Formation)

Plate 69 - Depth to top of the Hanadir Member (Qasim Formation)

Plate 70 - Depth to top of the Saq Sandstone

Plate 71 - Depth to bottom of the Saq Sandstone


Ministry of Water and Electricity – Kingdom of Saudi Arabia V

List of abbreviations

DMMR Deputy Ministry for Mineral Resources (now SGS)

DTM Digital Terrain Model

GIS Geo-Information System

MOWE Ministry of Water and Electricity

PKU Pre-Khuff unconformity

PTU Pre-Tawil unconformity

PUU Pre-Unayzah unconformity

USGS United States Geological Survey


Ministry of Water and Electricity – Kingdom of Saudi Arabia 1

1. INTRODUCTION

1.1. Previous work Previous work includes the earlier flow model of the Saq 1 project (1985), as well as the publications since then on the stratigraphy and structure of the northern Saudi Arabian sedimentary basins. The progress of geological knowledge since 1980 is mainly based, for outcropping formations, on the regional geological mapping carried out by BRGM and DMMR (now Saudi Geological Survey), and for the subsurface on the hydrocarbon exploration carried out by Saudi Aramco in the Nafud basin as well as in Central Arabia.

Such work has been published as 1:250,000-scale geological maps with their Explanatory Notes (DMMR) and as professional papers and publications (DMMR, GeoArabia, A.A.P.G. Bulletin).

1.2. General methodology The goal of this work package is to construct a numerical geological model based on the most recent scientific concepts and field data on geology, in order to improve our understanding of the flow model for groundwater-resource assessment.

The method for constructing a new numerical geological model is based on the knowledge of basin-stacking patterns, i.e. of how stratigraphic units and the main unconformity surfaces between are related to each other in a vertical and horizontal sense, and on identification and validation of 3D georeferenced data describing the structure of the aquifer systems from a geometric point of view. This work can be broken down into six steps.

The first step is to delineate the horizontal and vertical extent of several groups of geometrically related geological formations (packages) separated by major unconformity surfaces or faults. This has been done according to chrono- and litho-stratigraphical concepts and to a rough conceptual model of the basin structure defining the rules of the mutual horizon relationships.

The second step is to set up a correspondence chart between lithostratigraphy and hydrostratigraphy, i.e. between geological formations and their aquifer or aquitard properties, looking for a separation or connection between the different hydrologic units.

The third step, and most time-consuming, is to collect the necessary 3D (x, y, z) information for defining the shape of these horizons as well as the geometry of the layers throughout the project area and beyond. Such data originate from a great variety of sources, implying a major work of compilation, conversion to digital format and georeferencing with GIS tools.

The fourth step is to build several versions of the model using dedicated software (ArcGIS, GDM, EarthVision) and, through iterations, to correct and improve it by adding new layers and new control points until the model appears geologically correct.

The fifth step is the display of 3D views, cross sections, and isochore maps.

The sixth step is the calculation of the clipped output grids from the model and their export as x, y, z files toward the flow model.



2. LITHOSTRATIGRAPHY AND HYDROSTRATIGRAPHY

2.1. Lithostratigraphic units

Table 1. Lithostratigraphy within the project area

Age Units Sub-units Lithology Av. ThicknessQu Alluvium Sand sheets -Qu Gravel Gravel -Nafuds (Plio-Qu eolian) Eolian sand/lake dep. < 200mHarrats (III-Qu basalts) Basalt < 560mContinental Neogene Sand, gravel < 110mPre-Neogene unconformityMira - Umm Wu' al Fm. Limestone/cherts 135 - 560 mLina Mb.+U.E.R. Fm./ Belga series/Jalamid Fm. Complex / variable 0 - 120mHiatus

Aruma Fm. (exc. Lina Mb.) / Belga Series Khanasir/Hajajah or Hudayb/Zallum/Badanah Limestone / dolomite ~180m

Pre-Aruma unconformityMaliha /Mishrif Shale / Sdst.Qibah /Ahmadi, Rumaila Limestone/dolomiteMajma /Wara Sandstone

Pre-Wasia nconformity (Mauddud)Huraysan / Khafji, Safaniya SandstoneSallah Shale.siltstone, carb.Dughum Sandstone

Pre-Biyadh unconformityHith Anhydrite Anhydrite ~100m

Arab Fm. A, B, C, D Mb. Limest./Dolo/Anhydrite 55 - 130m

Jubaila Limestone Ju1 & Ju2 units Limestone ~ 90mHanifa Fm. H1 & H2 units Shale in H1 ~125m Tuwaiq Mountain Limestone T1, T2, T3 units Limestone ~185mDhruma Formation D7 unit Limest./Shale ~ 110mHiatusDhruma Formation D1 to D6 units Variable ~ 340m

Early Jurassic Marrat Formation Lower, Middle, Upper Mb. Sdst./Shale/Limest. ~ 125m HiatusMinjur Sandstone Lower / Upper Unit Complex /sandstone ~ 275m

J3 (J4 erosional) VariableJ2 SandstoneJ1 Siltstone

Sudair Shale Shale, anhydrite, salt ~ 310mKhartam Mb. Dolomite/limestoneMidhnab Mb. Shale/Dolo/AnhydriteDuhaysan Mb.Huqayl Mb.Ash Shiqqah Mb. Clastic, variable ~35m

Pre-Khuff UnconformityEarly Permian Unayzah Formation A, B, C, Mb. Sandstone 0 - 400m

Pre-Unayzah unconformityCarboniferous Berwath Formation Siltstone 0 - ~120m ?

Pre-Berwath unconformityJubah Fm. Upper' Jubah Sandstone ~110mPre Upper Jubah unconformityJubah Fm. Lower' Jubah ~260m

Murayr / Fiy'adh Mb. ~35mHammamiyat Limestone Mb. Carbonate /shale ~75mSubbat shale Mb. Variable ~80mQasr Limestone Mb. Limestone, variable ~20mSha'iba Shale Mb. ~50m

Tawil Formation Sandstone ~200-300mPre-Tawil unconformity

Sharawra Mb. Sandstone, siltstone 450 - >1000mQusaiba Shale Mb. 400-2000m

Uqlah Fm. ~15mZarqa + Sarah Fm. ~270m (< 500m)Pre-glacial unconformity

Quwara Mb. Sandstone 0-115mRaan Mb. ~35m (0-50)Kahfah Mb. Sandstone ~125m (115-175)Hanadir Mb. ~35m (25-50)

Saq Sandstone Risha / Sajir / Hilwan Mb. (Umm Sahm & Ram Sdst.) Sandstone ~ 700m

Burj Formation Limestone 0 - 200mSiq Sandstone. Sandstone ~200m (< 2000m)Unconformity

Infra-Cambrian Jibalah-type syn-tectonic basins Variable 0 - 3000mUnconformity

Pre-Cambrian Precambrian basement

Qalibah Fm.

Sandstone, congl.

Jauf Formation

Qasim Fm.

Neogene to Quaternary

Paleogene

Wasia Formation

Sandstone

Dolomite/anhydrite

Cambro-Ordovician

Mid Jurassic

Late Jurassic

Early Cretaceous

Triassic

Devonian

Ordovician

~380m

55 - >100m

Silurian

Late Permian 160-600m

300 - 350m

Biyadh Sandstone / Wasia Fm.

Jihl Formation

Khuff Formation

Late Cretaceous



Table 1 displays the lithostratigraphy restricted to the work area. This chart has been compiled from the BRGM-DMMR 1:250,000-scale geological maps for the surface geology and to "Arabian Plate Sequence Stratigraphy" (Sharland et al., 2004) for the most recent interpretation of subsurface data. The colours used to represent the lithology are: yellow for sandstone, orange for siltstone or mixed clastics, brown for shale, blue for limestone, green for dolomite, pink for anhydrite, violet for basalt and grey for metamorphic or crystalline rock.

Paleozoic rocks are the best represented in the study area, with a minor portion of the Triassic-Jurassic wedge in the eastern region and a transgressive cover of Late Cretaceous and Tertiary deposits in the northern region.

Many unconformities or disconformities (hiatuses) interrupt the succession. Several have a major importance through their relationship with tectonic events, like the pre-Berwath and pre-Unayzah unconformities linked to the Hercynian phase, and the pre-Aruma unconformity linked to the shelf tilting during Semail Ophiolite obduction in Oman. Other unconformities are more relevant of major transgressive phases like the pre-Khuff and the pre-Wasia unconformities.

Due to a major glacial event by the end of the Ordovician, deep paleo-valleys were incised and then buried by clastic peri-glacial or post-glacial deposits (Zarqa and Sarah Formations). Several other discontinuities have a minor or no impact on the geometry at the project scale, like the pre-Tawil unconformity (sequence boundary) and the pre-Marrat disconformity (hiatus by onlap).

2.2. Previous Saq hydrostratigraphy In the previous Saq project (1981-85), the aquifer systems were composed of one or several aquifer units separated by aquitards. Each aquifer or aquitard was identified by a code, with extra codes for undifferentiated comprehensive units (e.g. "Late Cretaceous (undivided)").

Several comments can be made:

'Lower Saq Sandstone' and 'Upper Saq Sandstone' are informal terms corresponding to facies changes from a lower fluvial unit to an upper littoral unit as described in outcrop in Central Arabia or in boreholes. In this area they could be assigned to the ‘Risha Member’ and to the ‘Sajir’+’Hilwan’ members respectively, which were defined on this basis (Delfour et al., 1982), but are now considered as obsolete terms. In northwest Arabia, the undifferentiated Saq Sandstone sensu lato covers the Siq, Quweira and former Umm Sahm and Ram sandstones. The latter is now considered as Saq Sandstone sensu stricto.

The former 'Tabuk Formation' is now subdivided into four units: the Qasim Formation (pre-glacial Ordovician, four members), the Zarqa and Sarah formations (glacial units), and the Qalibah Formation (post glacial Silurian, two members). The 'lower sandstone' (former TBK2) is an informal name for Kahfah Member, and the 'middle sandstone'' (former TBK4) corresponds to the Quwara Member of the Qasim Formation. The sandstone facies of the Quwara Member and of the Sarah Fm. are considered as a single unit for hydrological purposes.

Several subdivisions were made in the Jauf Formation, but are not distinguished in the flow model.

The previous hydrostratigraphy of the former Saq project used the term ‘Unayzah member’ for an aquitard at the base of the Khuff Formation. This lithological unit, consisting mainly of varicolored shale and dolomite with subordinate sandstone channels was defined (as well as other members) in outcrop by Vaslet in Delfour et al (1982) in the type section of the Khuff Formation (late Permian). However the Unayzah Formation (late Carboniferous-early Permian), mainly consisting of sandstone, is well known in subsurface as a HC reservoir. It is subdivided in three members, respectively A, B, C from top to bottom. Consequently the former ‘Unayzah Member’ was renamed Ash Shiqqah Member, formal name for the 'Basal Khuff Clastics'



(Filatoff et al., 2000, Vaslet et al., 2004). This aquitard remains thin at less than 30 m. In the previous flow model, the other aquitards (Midhnab Member and Sudair Shale were ignored, and only the cross-formational flows between Khuff and underlying aquifers through the 'Unayzah Member' were considered.

2.3. Aquifer systems

Table 2. Aquifer systems considered in the project area

Units Sub-unitsQu AlluviumQu Gravel Nafuds (Plio-Qu eolian)Harrats (III-Qu basalts)Continental NeogenePre-Neogene unconformityMira - Umm Wu' al Fm.Lina Mb.+U.E.R. Fm./ Belga series/Jalamid Fm.HiatusAruma Fm. (exc. Lina Mb.) / Belga SeriesPre-Aruma unconformityWasia Formation Variable Pre-Wasia nconformityMesozoic wedge (Triassic > Early Cretaceous) Variable Undiffer.Sudair Shale Major Sudair

KhuffAsh Shiqqah Mb. Weak Ash Shiqqah

Pre-Khuff UnconformityUnayzah Formation Fluvial/tidal UnayzahPre-Unayzah unconformityBerwath Formation Weak BerwathPre-Berwath unconformityJubah Fm. Tidal/deltaic JubahJauf Formation Weak JaufTawil Formation Braided TawilPre-Tawil unconformity

Sharawra Mb. Variable SharawraQusaiba Shale Mb. Major Qusaiba

Zarqa + Sarah Fm. Till / braidedPre-glacial unconformity

Quwara Mb. ShorefaceRaan Mb. Weak QAS3Kahfah Mb. Shorreface QAS2Hanadir Mb. Major QAS1

Saq Sandstone (Umm Sahm & Ram Sdst.)Burj Formation BraidedSiq SandstoneUnconformityInfra-Cambrian Weak UnconformityPrecambrian basement Substratum

Aquifer systems

QAS4

Cretaceous - Tertiary

Khuff Formation

Qasim Formation

SAQ

Qalibah Fm.

Table 2 shows the aquifer systems considered in the work area. Several assemblages were differentiated depending on the major aquitards and unconformities.

Underneath the thick Cambro-Ordovician sandstone series, the Infra-Cambrian is currently being explored. It occurs in syntectonic basins, located at great depths beneath Phanerozoic rocks and in grabens within the



Precambrian basement. Several such basins have been studied or explored in outcrop (Jibalah-type formations) or in subsurface (below the Rub al Khali).

The Cambro-Ordovician sandstones begin with the Siq Sandstone, outcropping in the southern edge of the great Nafud and remarkable in at Al Ula near Madain Sallah. In this area, and at shallow depth, it forms a single reservoir connected to the overlying Saq Sandstone. In the basin, and in Jordan near the southern Dead Sea, a transgressive limestone unit, the Burj Formation (<170 m) onlaps the Siq Sandstone and separates the two clastic units (Elicki et al., 2002). According to BRGM mapping, the Quweira Sandstone is a downthrown compartment of the Saq and thus does not stratigraphically differ from the Saq Sandstone.

The braided-river and shallow-marine sand-flats facies of the Saq Sandstone give generally excellent and clean reservoirs. The Hanadir Member at the base of the Qasim Formation, tough not very thick, is a fairly continuous shale member that forms the first aquitard. The Kahfah Member with its shallow marine sandstone (Tigillites ichnofacies) is the main reservoir of the Qasim Formation. The Raan Member shows a gradational coarsening-up sequence from dominant shale to sandstone and is commonly eroded by the glacial incised valleys.

During the end of the Ordivician, a major glacial episode occurred with a drastic sea-level fall inducing the formation of paleovalleys, locally very deeply incised down to the Saq Sandstone. They are filled by the tillite deposits of the Zarqa Formation, only locally preserved at the bottom of the valleys, and more generally by the Sarah Formation which mainly consists of permeable sandstone forming a good reservoir. These valleys have been explored in subsurface by Saudi Aramco (Figure 1) and mapped in detail in outcrop by BRGM/DMMR in 1:250,000-scale geological maps (Figure 2 and Figure 3).

Figure 1. Seismic interpretation of glacial paleovalleys in the Ha’il area (McGillivray and Al-Husseini, 1992; map from Aoudey and Al-Hajri, 1994)

Consequently, the Raan member is a weak aquitard with a common bypass from the Sarah Fm. to the Kahfah Member through the Quwara Member (both Tawil Fm.). Depending on the paleogeography, this phenomenon is more or less important, and areas where the Raan Member is absent have been delineated using the 1:250,000-scale BRGM/DMMR maps.



"

#

36° 39°38°37°

27°

29°

28°

TAYMA

TABUK

§

0 40 8020

Kilometres

Legend" Major town

# Minor town

Limit of Saq study area

Zarqa Sarah

Quwara

Raan

Kahfah

Hanadir

Other geological formations

Enlarged area

Figure 2. Extent of the Raan Member in outcrop in the Tabuk area (BRGM mapping)

In the Tabuk area (Figure 2), the Kahfah Member (in pink) is the most developed. The Raan Member (in green) separates the Quwara Member and Sarah Formation (respectively orange and brown) from the Kahfah Member. The paleo-valleys are moderately incised.

In the Qasim area (Figure 3), the Quwara and the Raan members are deeply eroded by the paleo-valleys and are present only as residuals. Consequently, the Sarah Member becomes connected with the Kahfah Member.



"

"

#

"

42° 44°43°

27°

28°

HA'IL

BAQ'A

UNAYZAH

BURAYDAH

§

0 30 6015

Kilometres

Legend" Major town

# Minor town


Zarqa Sarah

Quwara

Raan

Kahfah

Hanadir


Enlarged area

Figure 3. Extent of the Raan Member in outcrop in the Qasim area (BRGM mapping)

The Silurian shales of the Qusaiba Member act as the main seal above the Cambro-Ordovician aquifer system. Such shales are the main source rock for hydrocarbons, in particular in their basal portion ('Hot Shales'). In the same sedimentary succession, the Sharawra Member represents prograding pro-delta deposits. For this reason, these fine-grained deposits are sandier in their proximal part near the outcrop area, and muddier in their distal part in the basin. This unit was considered as an aquitard and grouped with the Qusaiba Member in the previous Saq project. Also, in spite of the pre-Tawil unconformity and of environmental changes, the break between the Sharawra Member (below) and the Tawil Formation (above) can be somewhat confusing in the more proximal setting, due to sediments entirely consisting of sandstone. According to Sharland et al. (2004) it is considered as a sand body, at least at shallow depth.

The Jauf Formation marks a marine transgression with retrograding sandstone. This formation was studied in outcrop by Janjou et al. (1997a, b) with a very recent synopsis by Al-Husseini and Matthews (2006). The marine and transitional environments induced deposition of interbedded limestone, sandstone and shale. Aquifer units may occur in the Qasr Limestone Member (including algal mounts) and in the transitional zone beneath the Jubah Formation (Fiy'adh or Murayr Member). However, the mud / sand ratio is generally high as shown by the synthetic section of Boucot et al. (1989; Figure 4).



Figure 4. Synthetic section of the Jauf Formation in northwestern Arabia (Boucot et al., 1989)



Figure 5. Paleogeographic domains of the Jauf Formation (Konert et al., 2001)

The paleogeographic map of Konert et al, 2001; Figure 5) delineates this shallow marine domain in the Nafud, while sandy deltaic deposits with good reservoir properties are present in Central Arabia.

For these reasons, the Jauf Formation must be considered vertically as an aquitard between the Tawil and Jubah formations, and horizontally as a multilayer system including some aquifer layers.

The Jubah Formation is essentially sandy with tidal to deltaic environments. It is related to the presence of the former 'Sakaka Sandstone'. This formation, exposed in the area of the Sakaka town, was for long time of an undefined age, Palaeozoic to Cainozoic (1:2 million-scale USGS geological map), and in particular Cretaceous. In fact, from the subsurface data, it is coeval to the Jubah Formation overlying the Jauf Formation (SKK 1), and in places, underlying the Aruma Formation to the Wasia Formation (SKK 2). The name 'Sakaka' is obsolete and not used in the new geological model, which considers only Jubah and Wasia formations in their respective stratigraphic position.



The Berwath Formation corresponds to isolated occurrences of Carboniferous siliciclastic rocks not found in outcrop (Al-Hajri and Owens, 2000). It consists of poorly dated, syn-Hercynian continental deposits. The reference section is in the stratigraphic well ST-8 located in the study area (~29°50’N, 42°E), where it .consists mainly of siltstone and shale with minor intercalated sandstone. Farther east (well Abu Safah-29) shale is dominant with minor intercalated dolomite. This unit is here considered as a local semi-pervious layer (weak aquitard).

Special attention should be paid to the next unit or Unayzah Formation. Above a major unconformity due to Hercynian movement (see 'Structure'), the Unayzah Fm comprises three reservoir members (A, B, C from top to bottom), consisting mostly of sandstone with paleochannels in the Unayzah C, and of minor intercalations of siltstone and shale.

It is a good hydrocarbon reservoir in Central Arabia where it may overly the Qusaiba Shale Member of the Qalibah Formation.



Figure 6. The Berwath and Unayzah formations in well ST-8 (Al-Husseini, 2004)



Figure 7. Geographic extent of the Unayzah Formation in subsurface (Konert et al., 2001)

The Ash Shiqqah Member of the Khuff Formation corresponds in fact to a diachronic clastic facies at the base of the Khuff, regardless of which member overlies it. It was described as the Basal Khuff Clastics and, by onlap, may be overlain by increasingly younger layers from the shelf to the basement. In outcrop, it was identified as the former 'Unayzah Member' in the north of the Central Arabian Arch by Vaslet et al. (in Delfour et al., 1982). It consists of sandstone, red and green shale, and mudstone and pink dolomite, and acts as a seal.

The rest of the Khuff Formation is a multi-layered system due to successive sabkha sequences, with porosity in basal dolomitic grainstones and anhydritic clays at the top. The Huqayl Member has the most contrasted lithology with carbonate benches and anhydrite layers. The Midhnab Member is laminated and fairly tight, but in contrast the Khartam Member, especially in its Triassic upper portion, exhibits a good primary and secondary porosity in oolitic beds (rock composed of coarse calcareous concretions). According to the project objectives, the Khuff Formation will be considered as a whole for the possible cross-formational flows between the Huqayl Member and the underlying aquifers through the Ash Shiqqah Member. The Khuff



Formation was studied in detail in subsurface by Al-Jallal (1989, PhD thesis, 1994) and in outcrop by Le Nindre et al. (1990) and Vaslet et al. (2005).

The Permian carbonates are absent on the Jordanian side where they are replaced by clastic deposits of the Hudayb Group. The Khuff formation is sealed by a regional major aquitard, the Sudair Shale (Early Triassic), which consists mainly of shales and evaporites. In the northwest corner of the project (Jordan), it is represented by the Hisban shale and Suwayma sandstone.

The rest of the Mesozoic up to the Late Cretaceous Wasia Formation forms a wedge thickening towards the northeast. It comprises clastic and carbonate formations (e.g. the Triassic Jilh Formation and Minjur Sandstone, and the Early Cretaceous Biyadh Sandstone). The anhydrite layers of the Arab Formation and the Hith Anhydrite act as an aquiclude that isolates the Trias-Jurassic assemblage from the Cretaceous. Due to its eastern position, this aquiclude is not involved in the hydraulic mechanisms studied in the project.

A transgressive wedge progressively onlapped and covered the northwest of the study area, up to the maximum Cenomanian-Turonian flooding expressed by the Wasia Formation. It includes major aquifers (Biyadh Sandstone) in reservoir horizons.

The next aquifer system includes the succession formed by formations of Late Cretaceous to Quaternary age, which unconformably overlap the older deposits down to the Early Paleozoic , spreading over the northwestern Arabia. The Wasia Formation in outcrop corresponds to the result of a major Cenomanian transgression. It comprises the three Majma, Qibah and Maliha members (Lebret et al., 1999), with a maximum flooding and carbonate deposition in the Qibah Member. The Majma Member includes sandstone units that can be good reservoirs although shale intercalations locally are thick in Central Arabia. The dolomite and limestone of the Cenomanian-Turonian deposits, if fractured or karstified, are well known in other contexts as a good aquifer as well. The Maliha Member consists of laminated siltstone with local sandstone channels. Although the Wasia is locally known and used for its water resource, its complex lithologicak make-up renders the aquifer properties of this formation highly variable (Le Nindre et al., in press). The extent of the Wasia Fm. to the far north is not well known. This is due to several factors: outcrops are very narrow north of Al Bid (28°15'N, 43°14’E) and are masked by the sands of the Great Nafud. In the Sakaka area, clay and sandstone assigned by Wallace et al. (1998) to the Wasia Formation onlap the Devonian Jubah Formation. Ziegler (2001) assumes a gap in the north of the project area, due to the Rutbah High.

The Aruma Formation was deposited after a very long hiatus during the Late Campanian and Maastrichtian, and pre-Aruma erosion. It has been subdivided into the Khanasir, Hajajah and Lina members. It consists of limestone and dolomite, with some intercalations of shale and evaporite in the Lina Member The base of the Lina Member is now dated as Paleocene (Thomas et al., 1999). Equivalent rocks in Jordan were described as Belga Series. In the northwest, the Late Maastrichtian and then the Eocene periods saw the deposition of phosphorite deposits in the Jalamid, Mira and Umm Wu'al formations (Riddler et al., 1983, Van Eck et al., 1984).

The overlying Neogene sandstone and conglomerates are good aquifers. The basalts of the Harrats are water-bearing as well with permeability due to discontinuities between flows or to the prismatic structure. In sand dunes, transient water storage occurs in the unsaturated zone or in older (Pliocene to Early Quaternary) well washed sands.



3. STRUCTURE

3.1. Schematic cross section of the Nafud basin Aoudeh and Al-Hajri (1994) propose a very schematic SW-NE cross section of the Nafud Basin from Tabuk to Ar’ar, perpendicular to the main dip. Though this section cannot be used as a data source for the model, it is useful for illustrating the general aspect of the basin.

0

Figure 8. Schematic SW-NE cross section of the Nafud basin (project area) - Aoudeh and Al-Hajri, 1994 [location of cross section shown on Plate 2 (Vol 13, Part 2)].

3.2. Variations in lithostratigraphy and hydrostratigraphy The framework of the new Saq flow model was carefully established. For this reason and as a working document for the project participants, charts were drawn up of the complete lithostratigraphy and hydrostratigraphy of the work area, including their lateral variations. They summarize the organization of the Nafud basin and of the Qasim area, highlighting the numerous unconformities that control the basin geometry.

This analysis of correlation and lateral changes was mainly demonstrated by the following documents:

− An extract of the 1:2-million-scale USGS geological map in the window of the project;

− A location map of the project boundaries and of the four reference stratigraphic charts chosen to illustrate four domains of the project area from NW to SE;

− A chart showing the former (Saq 1) stratigraphy and hydrostratigraphy;

− A chart of the overall stratigraphy of the Project area showing the correspondence with the hydrogeological units of the former model;

− Four charts giving the hydro- and litho-stratigraphy within the four representatives regions;

− A map of the pre-Hercynian subcrop (from Konert et al., 2001).

All charts show the formation and member names, the unconformities, the aquifers and the lithology. The variations in lithostratigraphy are due to the effect of several truncations related to unconformity surfaces, which are locally merged, e.g. the pre-Unayzah and pre-Wasia unconformities.



3.3. Role of the main unconformity surfaces Construction of the volume to be modelled should account for the major structures. These must be carefully reconstituted in order to build a reliable skeleton that will be fleshed out with the relevant intermediate stratigraphic limits. The final extent of the aquifer systems is highly dependant upon the geometry of the unconformity surfaces.

Above the Precambrian, the pre-Hercynian Paleozoic formations (Saq Sandstone to Berwath Formation) form a first assemblage ('Lower Wedge', Table 3). During the Carboniferous, fairly strong deformation of the platform occurred with subsequent erosion of the older deposits. The resulting truncation of the formations was strongest for the youngest ones. The geometry of these formations thus highly depends on the so-called 'pre-Unayzah unconformity' (PUU or PUZU). Moreover, the Berwath Formation was deposited during the deformation phases and rests itself unconformably as a residual unit on the older formations (namely Devonian) through a 'pre-Berwath unconformity'. The resulting extent of the pre-Unayzah formations is given by the subcrop map of Konert et al. (2001, Figure 9)

Figure 9. Subcrop map below the pre-Hercynian unconformity (Konert et al., 2001)

The shape of this surface has been reconstituted in the model. It implies a central high and two lateral slopes, one to the east controlling the volume of the Mesozoic wedge in central and eastern Arabia, and another steep one to the northeast controlling the development of the Mesozoic succession on the Jordanian side. This setting will have important consequences, e.g. the contact between Cretaceous and Silurian, or an apparent drastic reduction of thickness.

Below the PUU, the pre-Tawil unconformity (PTU) invoked by Wender et al. (1998) in the Ghawar seems to have no real geometric influence in the study area. It is defined in particular by a Silurian hiatus.



Above the PUU, the pre-Khuff unconformity (PKU) appears like a marine transgression over the basement, after a phase of exposure with formation of a laterite crust. The unconformity seems mainly due to an onlap surface with minor erosion.

The pre-Wasia unconformity is a major feature of the 1:2-million-scale USGS map, resulting in an apparent truncation of all older formations down to the Permian and probably the Early Paleozoic as well. Compared to the subsurface, the Wasia in outcrop is likely to represent the most transgressive units, coeval with the Wara, Rumaila and Ahmadi members. (Le Nindre et al., in press)

The pre-Neogene unconformity results in erosion, with incised paleo-valleys (e.g. in the Umm er Radhuma in the Eastern Province) and subsequent deposition of continental clastic deposits. Below this, the Eocene deposits commonly are residuals. These deposits are abundant in the Wadi Sirhan valleys and mimic the graben.

Depending on the location, several unconformity surfaces can be merged together.

3.4. Faults Three types of faults can be described within or near the study area. The major feature with an impact on the project is the Wadi Sirhan Graben, known as Azraq Graben in Jordan. In the east of the work area, near longitude 47°E in Central Arabia, the domain is naturally limited by a set of north-south faults to which hydrocarbon fields are related. In the northwest, i.e. the Tayma area, fields of minor, but narrow faults cut the Paleozoic along a NW-SE direction.

3.4.1. The Wadi Sirhan Graben

The structure of the Wadi Sirhan Graben is not visible on surface, but topographic maps clearlu show its morphology (Figure 10).



Wadi Sirhan

30°

31°

32°

39° 40°38°SAKAKA

AL QURAYYAT

700

600

800

900

1000

1100

500

1200

800

700

800

800

700

700

900

700

700

900

700

1100

800

700

900

700

800

800

700

800

800

900

700

800

900

700

800

800

700

900

700

700

800

600

800

900

700

900

900

LegendContour lines (50m)

Elevation (masl)472 ≤ z ≤ 500

500 < z ≤ 550

550 < z ≤ 600

600 < z ≤ 650

650 < z ≤ 700

700 < z ≤ 750

750 < z ≤ 800

800 < z ≤ 850

850 < z ≤ 900

900 < z ≤ 950

950 < z ≤ 1 000

1 000 < z ≤ 1 050

1 050 < z ≤ 1 100

1 100 < z ≤ 1 150

1 150 < z ≤ 1 200

1 200 < z ≤ 1 250

1 250 < z ≤ 1 300

1 300 < z ≤ 1 350

1 350 < z ≤ 1 378

§0 50 10025

Kilometres

Enlarged area

Figure 10. Topographic map of the Wadi Sirhan valley

Small faults were also mapped in the Devonian near Al-Jawf, which correlate fairly well with this structure.

In the subsurface, the Wadi Sirhan Graben is a narrow and very deep asymmetrical trough, with the shape of a half-graben: a steep slope on the northern flank and a gentler slope on the southern flank. The down-throw may reach 3 km in the deepest part below Jordan. The general dip in the graben is a slope to the north. The N-S cross section of Konert, et al. (2001) in Jordan shows the cumulated unconformity surfaces and the aspect of the graben, and suggest a main phase of rifting during the Cretaceous (Figure 11). An almost complete section of the Mesozoic since the Triassic is preserved on the northern side underneath the Harrat.



Figure 11. N-S section (AB) in the NW of the study area (Jordan) across the Wadi Sirhan (Azraq) Graben (Konert et al., 2001)

3.4.2. Other faults

Although the Central Arabian Arch appears like an east-west structure from surface mapping, the main structures in the east of the study area are N-S faults and anticlines, parallel to the Ghawar (Figure 9).

In the Tayma and Tabuk areas, the BRGM / DMMR mapping revealed a great number of faults, with a direction N150 parallel to the Red Sea inducing an offset of the Paleozoic formations (Figure 12).

100 Km



"

#

36° 39°38°37°

27°

29°

28°

TAYMA

TABUK

§

0 40 8020

Kilometres

Legend" Major town

# Minor town

Structures


Zarqa Sarah

Quwara

Raan

Kahfah

Hanadir


Enlarged area

Figure 12. Field of N150 faults in the Tayma-Tabuk area (BRGM-DMMR 1:250,000-scale mapping)

3.4.3. Paleohighs

Apparently permanent structures during the Phanerozoic are the basement paleohighs accompanying the Central Arabian Arch (Figure 9), confirmed by BRGM / DMMR stratigraphic borehole SHD1. The Ha’il Arch and N-S axes with the Rutbah High are post-Hercynian structures. These various structures are accounted for in the 3D model constructed for this project.



4. DATA SOURCES FOR THE MODEL

In order to be able to reconstruct a reliable 3D model of the aquifers-aquitards geometry, it was necessary to collect and to compile all available geological data dealing with the project area. A number of surface data are available from BRGM. Although they are of great value to control and update the outcrop geology, the project needs essentially subsurface data.

4.1. Surface data from BRGM background sources Surface data are taken from the published 1:250,000-scale geological maps surveyed by BRGM / DMMR, which were scanned and digitized to be included in the GIS. They cover almost the entire work area. In addition, USGS and Riofinex maps were used for the Jauf and Turayf areas. BRGM compiled this set of geologic maps in an ArcGIS data set. The geological information includes three main layers: polygons of the formation boundaries, and polylines of the structural elements. These data are projected into the specific coordinate system of the current Saq Project. A window including the project area is presented in Plate 3.

Another source of information consists of the BRGM / DMMR Open Files (internal reports) and Technical Records derived from these surveys.

4.2. Published data

4.2.1. Database queries

Subsurface results were published by Saudi Aramco, in particular in GeoArabia (GulfPetrolink, Bahrein) and in the A.A.P.G. Bulletin. In addition, systematic queries were done through geologic databases GeoRef and MEGRef.

- For GeoArabia, a fairly complete overview of the Journal and of the Special Publications was performed, covering an essential and useful documentation;

- From GeoRef, 297 references in 23 files (888 Ko) are sorted by formation;

- MEGRef (Gulfpetrolink) contains a collection of references on Middle East geology.

-

4.2.2. Base document: Saq project, geological setting of the project area

A base document on the geological setting of the Project area was compiled mainly from GeoArabia publications, with minor additions of other papers. It consists of a voluminous PowerPoint presentation explaining the configuration of the project area on successive slides, especially in subsurface. Its purpose is:

- To have a common project-reference document, helpful for all the researchers involved in the project;

- To present the information collected and stored for the 3D modelling.

The presentation includes so far 54 slides with a size on disk of 240 Mb and is being updated.

4.2.3. Structure, facies, paleogeography

Much of the structural, facies and paleogeographical information was gathered from GeoArabia and Aramco publications. The most important of these are:

- Structure map of the basement: Konert et al. (2001);

- Paleogeographic maps of the Paleozoic: Konert et al. (2001);



- Paleogeographic maps of the Post-Paleozoic: Ziegler (2001);

- Structure map of the base of the Qusaiba Shale Member: Aoudeh and Al-Hajri, 1994, Abu Ali et al., 1999;

- Thickness of the Qusaiba Shale Member: Mahmoud et al., 1991, Jones and Stump, 1999;

- Thickness of the Qalibah Formation: Mahmoud et al., 1991;

- Structure map of the top Unayzah Formation: , Abu Ali et al., 1999;

- Thickness of the Khuff Formation: Al-Jallal, 1994.

Complementary data on the Qasim Formation were gathered from previously compiled data for the first Saq project.

4.3. Boreholes

4.3.1. Saq 1

During the Saq 1 project, a thesaurus of 96 reference wells was created: 30 of these were drilled by BRGM and well logs were measured (86-SAU-170-EAU, Volume 2: Water Studies, appendix 2). The other wells are existing wells that were logged and interpreted by BRGM. The total is summarized in a table (86-SAU-170-EAU, Volume 2: Water Studies, Attached Document, Reference Wells Data). In the present project, these data have been carefully culled for their reliability and a few interpretations were discarded or corrected. The results are stored in an Excel file.

4.3.2. Professional papers

Well logs were also extracted from professional papers that usually do not mention the coordinates. To be used in the model, they have to be georeferenced, using location maps and GIS facilities. Then they have been added to the borehole database. These data complete elevations of the formation tops or bottoms. This is especially the case for the Devonian and Carboniferous, in order to pick either the PUU or the formation limits (Al-Hajri et al., 1999; Al-Husseini, 2004).



5. GEOLOGICAL MODELLING

5.1. Methodology The base of geological modelling is to arrive at a proper reconstruction of selected geological elements. In this case, we are interested in faults, faults blocks, horizons with their stacking rules in the stratigraphic succession, and unconformity surfaces including the topographical surface. The shape of all these features should be defined in a three-dimensional geographic coordinates system of x, y, z. For the Saq Project, we have chosen a dedicated projection, derived from the projection of the USGS 1:2-million-scale map of the Arabian Peninsula1. The dimensions of the model are based on the work area boundaries ('Area 1') with a peripheral extension in order to retain optimal geometric and hydraulic constraints within the Project area.

To achieve a realistic representation, several steps are needed:

- Analysis of the earlier Saq 1 flow model was based on the VTDN software. This had specific facilities for estimating flow within and between the aquifers that are not necessarily all compatible with a realistic geological representation. Moreover, knowledge of the subsurface was less than today. Nevertheless, an analysis of its content with up-to-date tools helps in a better understanding of the former model and of the possible re-use of its data and results.

- All geologic data must be collected that can be helpful for 3D reconstruction, such as well logs, structure and isopach maps, subcrop maps, and facies maps (see Chapter 4 on Data Sources).

- All types of available geological documents have to be homogenized and converted into compatible digital formats. Specifically, geographic coordinates and the appropriate projection (Saq Lambert conformal conic) must be assigned to maps and boreholes. This operation is done with the ArcGIS 9 software chosen for the project. It includes in particular scanning and rectification of the various types of maps containing pertinent information, conversion of the borehole coordinates into the right system, and digitizing of borehole locations, contour lines, formation boundaries, etc. This was done according to the existing reference BRGM GIS of the Saq Project area and the Digital Chart of the World (Figure 13).

- The model volume must be defined (in metres): Saq Project projection (Lambert conformal conic): x min 3,000; x max 1,197,000; y min 93,000; y max 997,000; z min -12,500; z max 2500, with a mesh size of 2,000 and the first data point at 3,000-93,000, i.e. 1194 x 904 x 15 km and 598 x 453 meshes at 2 km steps.

- The fault system has to be homogenized into a single style of faults cuts and boundaries in spite of the representation variations found in the literature. The only faults to be selected according to their major effect are those of the Wadi Sirhan (Azraq) graben. The style is a simplification of the map of Aoudeh et al. (1994), close to the subcrop map of Konert et al. (2001).The other faults are marginal to the model, or of minor importance compared to the model scale. Some of them were introduced as local vertical faults.

1 Lambert conformal conic; First standard parallel 26°N; second standard parallel 30°N; latitude of origin 28°N; central meridian 40°E; scale factor 1.0000; false easting 500,000; false northing 500,000; datum: Aïn el Abd, 1970.



E E E E E E E E E E E E E










Figure 13. Georeferenced and rectified map of the basement structure (structure after Konert et al., 2001)

- Start of the step-by-step reconstruction by using reference horizons, in particular the Basement structure, the bottom of the Qusaiba Shale and the topography. The topography (Digital Elevation Model) has an original step of 900 m. After this, a first version of the pre-Unayzah unconformity (PUU) was added, controlloing the boundaries of all older formations. The construction of the PUU and of the depending horizons was iterative, using all available data (subcrop map, already constructed structure maps, and boreholes)

- Complete the construction of the pre-Unayzah formations: first the Qasim Formation with its four members and the top of the Saq Sandstone, then the Devonian and Carboniferous units. The Qasim Formation is poorly documented in the literature, and results of the previous Saq 1 project were used (thickness from the isohypse maps, and reference wells). However, the isohypses were adjusted on the reference given by the more recent knowledge of the Qusaiba Shale and the outcrops of the 1:250,000-scale maps. The Devonian and Carboniferous formations are modelled from outcrops (if any), from available stratigraphic wells and from the constraints of the PUU.

- Several horizons representing the Mesozoic transgressive wedge were then added to this base. They are the Unayzah Formation, Ash Shiqqah Member of the Khuff Formation, Khuff carbonate, and Sudair Shale.

- The results of the first geological model were exported to the flow modeller as x, y, z top values of each formation where it exists.



5.2. The 3D model

5.2.1. Model extent

The volume of the model in metres in the Saq Project projection (Lambert conformal conic) is: x min 3,000; x max 1,197,000; y min 93,000; y max 997,000; z min -12,500; z max 2500, with a mesh size of 2,000 and the first data point at 3,000-93,000, i.e. 1194x904x15 km and 598x453 meshes.

These coordinates correspond roughly in latitude and longitude to 35° to 47° long. E and 24° to 32°30 lat. N, and include the work area. To the NE and NW, parts of Jordan, Syria and Iraq are included in the model. The extension into Jordan is important for flow modelling in the Wadi Sirhan region, but the extension into Iraq is poorly documented and of minor interest. To the east, the model is limited by the main north-south faults and anticlines parallel to Ghawar, for construction facility. In fact the study area is restricted to 45° long. E.

5.2.2. Fault blocks

Due to the presence of the Wadi Sirhan Graben, the model was subdivided into three fault blocks (Figure 14): block 1 inside the graben and its prolongation to the south-east; block 2 east of the graben (central and eastern Arabia side); and block 3 west of the graben (Jordanian and northwestern Arabian side) The faults were mapped from the literature as explained above in “Methodology”, and modelled with a sub-vertical pitch towards the graben on the basis of the respective isohypses of basement and Qusaiba Shale.

Figure 14. Fault blocks

5.2.3. Horizons modelled

All outcropping horizons were in priority matched to the outcrops by using a combination of the digital geological map (from GIS) and of the digital terrain model (DTM), regardless of the subsurface data. The modelled horizons are from bottom to top:

1. Top of the Basement, according to Konert et al. (2001), with minor corrections to conform to the field-truth of surface mapping in the northwest. Minor discrepancies exist between the isohypse map and the paleogeographic maps of these authors near the Central Arabian arch; nevertheless, their isohypse values were retained as a reference



2. Top of the Infra-Cambrian. Considering the great thickness of sediment accumulated in deep sub-basins, it was necessary to differentiate, even roughly, the Saq-related formations from the other formations forming the deep substratum. The top Infra-Cambrian was fixed according to the basin model of Dyer and Al-Husseini (1991, Figure 15), the section of Aoudeh et al. (1994, Figure 8) and the basement isohypse map of Konert et al. (2001) in order to partially fill the deepest areas of the basin.

3. Top of the Siq Sandstone, controlled by the outcrop and assuming a maximum thickness of 700 m for the Saq Sandstone and ~170 m for the Burj Formation where present.

4. Top of the Burj Formation, controlled by the outcrop in Jordan (Elicki et al., 2002) and assuming a maximum thickness of about 170 m.

5. Top of the Saq Sandstone (sensu stricto) and the coeval Umm Sahm and Ram sandstones in Jordan.

6. Top of the Hanadir Member of the Qasim Formation.

7. Top of the Kahfah Member of the Qasim Formation.

8. Top of the Raan Member of the Qasim Formation.

The last four horizons were modelled by kriging of the thickness values and adjusting their elevation (‘z’) with outcrop data, borehole data and the base of Qusaiba Member as a reference horizon. Surface mapping helps in defining the areas where Kahfah and Quwara-Sarah become connected. This variation will be introduced in the flow model as permeability data, rather than as geometric data that are impossible to model with the present knowledge at the model scale.

9. Top of the Quwara Member of the Qasim Formation and the Zarqa-Sarah glacial formation as a whole. In fact this horizon was mapped as the base of the Qusaiba Formation from literature data. This horizon is taken as a reference.

10. Top of the Qusaiba Member by using thickness maps (Mahmoud et al., 1992; Aoudeh and Al-Hajri, 1994; Jones and Stump, 1999).

11. Top of the Sharawra Member, i.e. top Silurian: this horizon can be modelled once the PUU surface has been constructed. Its geometry, conformable with the underlying top of the Qusaiba, is controlled by outcrops, boreholes giving the base of the Tawil Formation, and also by the intersection line of this horizon with the PUU surface.

12. Top of the Tawil Formation

13. Top of the Jauf Formation

These three horizons were modelled using outcrops and boreholes, in conformity with the top of the Tawil Formation.



Figure 15. Infra-Cambrian basins (in Sharland et al., 2001, adapted from Dyer and Al-Husseini, 1991)

14. Pre-Berwath unconformity. The top of the Jubah Formation corresponds to a limited extent to the base of the Berwath Formation mapped on the pre-Hercynian subcrop map. However, the Berwath unconformably overlies the Devonian. Therefore the modelled horizon is the base Berwath unconformity surface, truncating the Devonian. In the final export, the output grid corresponds to the Jubah Formation.

15. Pre-Unayzah unconformity: as explained above, it is constructed using a complex data set (outcrop, boreholes, structure of horizons already modelled, subcrop map). It also defines the top Berwath in the model.

16. The top of the Unayzah Formation (Unayzah-A Member), which occurs mainly in Central Arabia, is given by the map of Abu Ali et al. (1999) and by several wells.

17. The Ash Shiqqah Member of the Khuff Formation (former Unayzah Member, equivalent with the Khuff-E informal subsurface unit or “Khuff Clastics”) seals the paleoreliefs under the pre-Khuff unconformity (PKU). Where not controlled by wells, it is assumed to be the first 35 m of the Khuff Fm. above the Unayzah-A, according to its common thickness reported by Le Nindre et al. (1990) and Al Jallal (1994).

18. The top of the Khuff Formation is constructed with the isopach map of Al-Jallal (1995) and the Sudair / khuff contact in wells, and matched to outcrop data.



19. The Sudair Shale, according to Szabo and Keradpir (1978) and Le Nindre et al. (1990), was considered as very continuous with a thickness of ~318m following the top-Khuff structure.

20. The Triassic-Jurassic wedge (Jilh Formation to Jubaila Limestone) is limited at the top by the base Arab D (see next horizon) and matched to outcrop data. It includes the Jilh-Minjur unit and the Dhruma reservoirs.

21. The Arab-Hith-Gotnia unit: Control data being mostly outside the work area, this horizon was matched to outcrops (base and top) and constructed by reference to the top-Sudair and the base-Aruma by using thickness data from outcrops and in the Abu Jifan field northeast of Riyadh.

22. The pre-Aruma wedge is modelled by using the pre-Aruma (or equivalent) unconformity structure from outcrops and wells. It includes Lower and Upper Cretaceous deposits up to the Wasia Formation and in particular the Biyadh-Wasia reservoirs.

23. The Maastrichtian-Eocene assemblage corresponds to a thin carbonate sheet following the pre-Aruma unconformity. It was modelled by using mostly outcrop data, wells and pseudo-wells to control the thickness

24. The Neogene and more recent clastic deposits eroded from the older carbonate platform are deduced from the remaining topographic relief, except for the nafuds and harrats.

25. Nafuds include the high sand dunes of the Great Nafud and the various nafuds located in elongated depressions that generally correspond to softer (silty and argillaceous) formations (e.g. Nafud as Sirr, Nafud Ath-Tuwayrat). They were modelled by using topographic data and the elevation data at the boundaries.

26. Harrats were modelled like the sand dunes by using topographic and elevation data.

The total of the horizons modelled is 26.

5.2.4. Results

The 26 horizons were modelled using the GDM (BRGM) and EarthVision (Dynamic graphics Inc.).

Pre-Hercynian formations

At the bottom, the basement (Figure 16) shows a contrasted topography with troughs and highs. Troughs reach depths down to 12,000 m below sea level. Highs and troughs are located along a NNW-SSE direction, parallel to the outcrop strike in the Qassim area. The Wadi Sirhan Graben is a huge asymmetrical structure that cuts the basin into two regions. The Tabuk - Tayma area is relatively flat.



Figure 16. Structure of the top of basement, view from the SE (colour zone = 1,000 m)

The Infracambrian (which is not really known so far) fills the paleotopography of the basement and can be very thick. It is overlapped by the Siq Sandstone that seals the remaining topography. The marine Burj Formation carbonates on-lap over the Siq Sandstone. During deposition of the Saq Sandstone, the landscape was supposed to be quite flat (Figure 17). The Saq is connected to the Siq Sandstone as a single aquifer in the south of the study area, where the Burj is absent, and shows gaps in Central Arabia and truncations by the PUU in the northwest.

Figure 17. North-south cross section (Ha’il area, x=400,000m): IC, Siq, Burj, Saq.

100 Km

4 km

SiqSandstone

SaqSandstone

InfracambrianW. W. SirhanSirhan ((AzraqAzraq) ) grabengraben

BurjFormation

100 Km

4 km

SiqSandstone

SaqSandstone

InfracambrianW. W. SirhanSirhan ((AzraqAzraq) ) grabengraben

BurjFormation



The Qasim Formation (Figure 19) is very thin compared to the whole model. The relative thickness of the four members is not well known far away from the outcrops and, as explained above, the Kahfah-Raan-Quwarah-Sarah complex may have a variable permeability due to the role played by paleovalleys. The Sarah Formation, just below the Qusaiba source rock, may also be a hydrocarbon reservoir (Abu Jifan). Its upper surface corresponds to the base of the Qusaiba Shale Member. The Qasim Fm. shows gaps and truncations in Central Arabia, to the northeast (area not documented north of the Arabian Gulf) and in the Wadi Sirhan Graben through the effect of the PUU.

N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas

Boundary ofthe Saq Project

Model extent

500 m

-1500 m

-1000 m-500 m0 m500 m

-1500 m-1000 m-500 m

0 m

-450

0 m

-2500 m-2000 m

-3500 m

500 m

-400

0 m

-3500 m

-3000 m

-2500 m

-2000 m

-1500 m

0 m

500 m

-500 m

-500 m-1000 m

-1500 m

0 m

500 m

-1000 m

-500 m

0 m

Main cities

Baq'aBaq'aBaq'aBaq'aBaq'aBaq'aBaq'aBaq'aBaq'a

Ad Daw adimiAd Daw adimiAd Daw adimiAd Daw adimiAd Daw adimiAd Daw adimiAd Daw adimiAd Daw adimiAd Daw adimi

Al QurayyatAl QurayyatAl QurayyatAl QurayyatAl QurayyatAl QurayyatAl QurayyatAl QurayyatAl Qurayyat

Ha'ilHa'ilHa'ilHa'ilHa'ilHa'ilHa'ilHa'ilHa'il

JubbahJubbahJubbahJubbahJubbahJubbahJubbahJubbahJubbah

Daw mat-al-JandalDaw mat-al-JandalDaw mat-al-JandalDaw mat-al-JandalDaw mat-al-JandalDaw mat-al-JandalDaw mat-al-JandalDaw mat-al-JandalDaw mat-al-Jandal

TabukTabukTabukTabukTabukTabukTabukTabukTabuk

UnayzahUnayzahUnayzahUnayzahUnayzahUnayzahUnayzahUnayzahUnayzahBuraydahBuraydahBuraydahBuraydahBuraydahBuraydahBuraydahBuraydahBuraydah

SajirSajirSajirSajirSajirSajirSajirSajirSajir

AL UlaAL UlaAL UlaAL UlaAL UlaAL UlaAL UlaAL UlaAL Ula

TaymaTaymaTaymaTaymaTaymaTaymaTaymaTaymaTayma

SakakahSakakahSakakahSakakahSakakahSakakahSakakahSakakahSakakah

QibahQibahQibahQibahQibahQibahQibahQibahQibah

Top elevation of Quwarah-Sarah (m msl)

1000 to 1500500 to 1000

0 - 500-500 - 0

-1000 to -500-1500 to -1000-2000 to -1500-2500 to -2000-3000 to -2500-3500 to -3000-4000 to -3500-4500 to -4000-5000 to -4500

Figure 18. Structure of the base of Qusaiba Shale Member (Qalibah Formation)

The Qalibah Formation (Figure 18), including the Qusaiba Shale Member and the Sharawra Member, encompasses much of the Silurian period. At the top, the Tawil Formation rests on the Sharawra Member with an intra-Silurian hiatus (PTU). The Qusaiba shale has been intensively explored and its extent is well known.



N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

200 m

200 m

200 m

400 m

600 m800 m1000 m12

00 m

200 m

400 m

1000 m

1400

m

400 m

200 m

400 m

800 m

600 m

1200 m

1800 m

1400

m

1600

m

1600 m1200 m

800

m12

00 m

1400 m

1600

m

400 m

200

m

400 m

400

m

200 m

200 m

200 m

Main cities














Thickness of Qusaiba (m)

0 - 200200 - 400400 - 600600 - 800800 to 1000

1000 to 12001200 to 14001400 to 16001600 to 18001800 to 2000

Figure 19. Thickness of the Qusaiba Shale Member (Qalibah Formation)

The Devonian Tawil, Jauf and Jubah formations occupy a limited area in the centre of the Nafud basin. They are fairly tabular but they are truncated by the PUU to the east and west, though more drastically in the area of the Wadi Sirhan Graben. This effect is visible through the thickness reduction shown in the cross section of Konert et al. on the Jordanian side (Figure 11, above).

The Berwath Formation is present only as residuals and rests with an unconformity on the Devonian (Figure 20).



Figure 20. Pre-Hercynian subcrop underneath the pre-Unayzah unconformity (PUU)

Figure 21. Onlap of the pre-Hercynian formations by the marine Permian Khuff Fm. (in blue)

The Unayzah Formation comprises sandstone from various origins and has been mainly explored in Central Arabia, in the west of the project area, where it forms hydrocarbon reservoirs. Fairly thin and beginning with paleovalleys, its extent is still under exploration. Within the project area, it exhibits broad gaps on the Central Arabian highs. Above, the Ash Shiqqah Member, of mixed lithology, is the first layer to initiate the



retrogradation towards the west of the Permian-Mesozoic wedge, which progressively onlaps the older Hercynian unconformity surface. It is followed by the Late Permian transgression of Khuff carbonates (Figure 21). According to Al Jallal (1994), the Khuff exhibits only poor to variable reservoir quality in the study area. In Jordan (NW corner of the model), this period correspondsing to the deposition of clastics of the Hudayb Group.

During the early Triassic, the Sudair Shale forms a continuous drape of shale and evaporites that acts as a major seal over the Jubah Formation).

During the rest of the Triassic and the Jurassic, a thick sedimentary wedge was deposited in Central Arabia and farther east. In Jordan, the transgression reached the northwest of the study area only during the Middle Jurassic, outcrops of which are visible along the Dead Sea, north of y=890,000 (~31°30’) and correctly displayed by the model.

In Central Arabia and towards the Gulf, the Jurassic cycle is sealed by the Arab Formation and the Hith-Gotnia anhydrite. Due to their geographic distribution, these deposits have no impact on the hydraulics within the study area.

During the Cretaceous, an major transgression progressively overlapped all older formations from east to west. One of the consequences is a confinement of the Jubah aquifer by the combined action of the Berwath, Sudair, and lower Wasia shales. The basal shales of the Wasia Formation are exploited in Central Arabia (Khushaim Radi) as well as in the Sakaka area where they overly the Jubah sandstones. The Biyadh-Wasia reservoirs are most developed in Central and northeastern Arabia and the relationships between outcrop and subsurface are complex (Le Nindre et al., GeoArabia 2006).

Finally the drowning of the platform is achieved by the Maastrichtian, Paleocene and Eocene carbonates, including the Turayf phosphate deposits (Figure 22).

The model is completed by adding the recent deposits and the basaltic plateaus (Harrats). The sand dunes play an important hydraulic role in the recharge of the underlying subcropping aquifers, offering a large surface at the scale of the Great Nafud.

The structure of the individual geological layers reconstructed by the geological model is presented in Plates 7 to 71.



Figure 22. Completed model with Neogene sand sheets, sand dunes and Harrats

5.2.5. Model contribution to understanding of the structure

Great progress has been made by constructing the 3D model and using the 3D modeller. The first improvement was to identify properly and separately the structure of the Wadi Sirhan Graben, which cuts deeply into the Nafud basin, following the strike of the Basement edge from Central Arabia.

Several cross sections through the model illustrate the structure mainly as the result of Hercynian uplift (several thousands of metres), followed by deep truncations, especially in the northwest. In a second stage, this structure was cross-cut by the Wadi Sirhan (Azraq) Graben, which complicates the understanding of the final result. One of the main effects is the rapid disappearance of the Devonian and the unconformable contact of a thick Cretaceous-Tertiary succession over Early Paleozoic rocks. At depth, on the Jordanian side, a sub-continuous series from Triassic to Tertiary exists. Due to the great depths of the basin, the existence of some of these complications (e.g. Triassic) will have no consequence for the groundwater management of shallower aquifers.

Looking in particular at the aquifer units, a north-south section (plate 4) illustrates the N-S wedge. All Early Paleozoic aquifers are present. At great depth, the Cambro-Ordovician (Siq+Burj+Saq) appears to be very thick. In spite of changing facies (prograding delta front), the Sharawra Member (orange) is here considered as partly sandy and connected to the Tawil Formation. The Jauf Formation, the hydraulic behaviour of which is complex, forms a vertical seal to the Jubah Formation, although it is water-bearing as well. The system is capped by the Maastrichtian-Eocene succession.

From west to east, the continuity of the aquifer systems can be disrupted by the down-thrown of faults on both sides of the graben. In particular, the Saq and Qasim aquifer systems come in contact with impervious layers of the Bbasement and Qusaiba shale. In the northwest, the Paleozoic sequence is drastically



truncated and the Saq aquifer becomes disconnected at the bottom of the graben (Plate 5). The Cretaceous-Eocene becomes the main aquifer in the graben, and fault-related vertical connections are possible.

The pre-Berwath and pre-Unayzah unconformities are here clearly visible (noted 'PUU', Berwath is left empty in white in the section). The Cretaceous and Maastrichtian-Eocene (in blue) unconformably fill the graben.

A north-south cross-section (Plate 6) demonstrates the drastic thickening of the Cretaceous-Tertiary series (white and blue) and the dip of the Early Paleozoic in the graben area. It helps to understand the relationship between the upper sequence and its related aquifers, with the Early Paleozoic one. Practically, due to the great depths, the only aquifers to exploit here will belong to the upper assemblage.

On the eastern side, the broad Mesozoic-Cainozoic wedge opens in Central and Eastern Arabia towards the east.

In Central Arabia (south of the Qassim area, in the Al Faydah and Ad Dawadimi quadrangles) the Saq and Qasim formations pinch out against basement paleohighs. In this area, the Qusaiba shale is reduced or absent.



6. CONCLUSIONS

6.1. Implications for flow modelling − The Saq Sandstone is a huge aquifer compared to the other ones.

− The Hanadir Member should be a continuous seal.

− The Qasim aquifer will develop good reservoir properties where the Sarah Formation is thick and connected to the Kahfah Member by erosion of the Raan Member. This should be attempted using a regional zoning of the permeability values. The Sarah Formation is a good reservoir (e.g. Abu Jifan oil field). Otherwise, the Qasim Formation is considered by petroleum exploration as a rather poor reservoir, except for local water resources in the Kahfah Member.

− The Sharawra and Tawil formations will be merged, but a differential permeability should be used to account for the variable and less-permeable properties of the Sharawra Member. In the first Saq project, this member was merged with the Qusaiba Member, which is probably true at depth in the north, but not closer to the outcrop.

− Differing from the first Saq project, the Jauf Formation will be considered as a semi-pervious system including some water resources, but acting as a confining unit between Tawil and Jubah.

− The so-called Sakaka Sandstone is here known as the Devonian Jubah Formation, which is a good reservoir.

− The Berwath acts as local screen or seal, the extent of which is largely assumed. Its role is completed by the effect of the Sudair Shale and of the basal Wasia Formation, both unconformably ovelying the Jubah Formation sandstone.

− One of the most important innovations of the flow model will be a better knowledge of the basement structure, of the PUU, and of the Wadi Sirhan (Azraq) Graben in terms of their geometric and connecting implications.

− Attention should be paid to the difference in scale between modelling of a basin measuring 1200 x 900 x 15 km and the analysis of aquifers functioning at very local scale. The complications known at local scale, in particular close to outcrops, though well documented, cannot be modelled or extrapolated at such a dimension and will request special studies.

6.2. Export to the flow model The 26 layers of the current geological model have been exported to the MARTHE software package for preliminary tests and simulations.

In a first step, the EarthVision program compiles "horizon tables" that create a topology. The tables refer to the initial whole horizon grids, the fault blocks; the faults and the polygons defining the formation boundaries. The horizon is clipped according to the contact with the adjacent formations in the succession, using the polygon as a limit. Then the output grid is created.

In a second step, the EarthVision grids can be exported under several standard formats (Landmark, Reservoir simulator, etc.) including scattered data files (ASCII .dat files) containing x, y, ztop, column number, row number, and, optionally, header and null nodes.

Through several customized routines, these files are coverted into GDM, Access or ArcGIS format for storage and visualization by the GIS software of the project.



In parallel, these files are input into the mathematical groundwater model as grids at a step of 2 km, for flow simulations.

Then a dialogue is established between the geologist and the hydrogeologist, to interpret the observed hydraulic behaviour and calibrate the model according to the geological and hydrogeological parameters.



References

Al-Hajri S.A, Filatoff J., Wender L.E. and Norton A.K. 1999. Stratigraphy and operational palynology of the Devonian System in Saudi Arabia. GeoArabia, vol. 4, n° 1, 1999, pp. 53-68

Al-Jallal, I.A. (1989) - Depositional environments, Diagenesis and Reservoir Characteristics of the Permian Khuff Formation in Eastern Saudi Arabia. PhD thesis, University of London, Imperial College, Department of Geology, London, Saudi Aramco, Dhahran, 536 p. (including 30 plates with 143 rock photographs, 118 fig. and cross sections, 4 tables, 4 appendices).

Al-Jallal I.A. (1994) - The Khuff Formation: Its regional reservoir potential in Saudi Arabia and other Gulf Countries; depositional and stratigraphic approach. Geo '94. Selected Middle East Papers from the Middle East Geoscience Conference. April 25-27, 1994, Bahrain, pp 103-119. Edited by Moujahed I. Al-Husseini, Published by Gulf PetroLink, Manama, Bahrain.

Al-Hussein M.I. (2004) – Pre-Unayzah unconformity, Saudi Arabia. GeoArabia, Special publication n°3 Carboniferous, Permian and Early Triassic Arabian Stratigraphy. Pp. 15-59, 2004 Gulf PetroLink, Bahrain.

Al-Hussein M.I. and Matthews R.K. (2006) – Devonian Jauf Formation, Saudi Arabia: Orbital second order depositional sequence 28. GeoArabia, vol. 11, n°2, 2006, pp. 53-70. Gulf PetroLink, Bahrain.

Aoudeh S.M. and Al-Hajri S.A. (1994) – Regional distribution and chronostratigraphy of the Qusaiba Member of the Qalibah Formation in the Nafud Basin, northwestern Saudi Arabia. Geo ’94, The Middle East Petroleum Geosciences. Vol. 1. pp 143-154. April 25-27, 1994, Bahrain. Edited by M.I. Al-Husseini, published by GulfPetrolLink, Bahrain.

Boucot A.J., McClure H.A., Alvarez F., Ross, J.R.P., Taylor D.W., Struve W., Savage N.N., and Turner S.S. (1985) – New Devonian fossils from Saudi Arabia and their biogeographical affinities. Senckenbergiana Lethaea, vol. 69, pp. 535-597.

Delfour J., Dhellemmes R., Elsass P., Vaslet D., Brosse J.M., Le Nindre Y.M., Dottin O., 1982 - Geologic Map of The Ad Dawadimi Quadrangle. Sheet 24G, Kingdom of Saudi Arabia. Scale 1:250.000. Geoscience Map Gm-60 A - Jiddah, Saudi Arabia A.H. 1403. Ministry of Petroleum and Mineral Resources.

Dyer R.A. and Al-Husseini M. (1991) – The western Rub’ Al-Khali Infracambrian system. In Proceedings of the Society of Petroleum Engineers, Middle East Oil Show, Bahrain. Paper SPE 21396.

Elicki O., Schneider J. and Shinaq R. (2002) - Prominent facies from the Lower/Middle Cambrian of the Dead Sea area (Jordan) and their palaeodepositional significance. Bull. Soc. géol. Fr., 2002, t. 173,n o 6,pp. 547-552.

Filatoff, J. and Stephenson M. (2000) - Sedimentary and palynofloral successions of the Permo-Carboniferous in Saudi Arabia. 4th Middle East Geosciences Conference, GEO 2000. GeoArabia, Abstract, v. 5, no. 1, p. 87-88.

Janjou D., Halawani M.A., Al-Muallem M.S, Robelin C., Brosse J.M., Courbouleix S., Dagain J., Genna A., Razin P., Roobol M.J., Shorbaji H. and Wyns R. (1997a) – Explanatory notes to the geologic map of the Al Qalibah quadrangle, Kingdom of Saudi Arabia. Geoscience Map GM-135, scale 1:250,000, sheet 28C.



Deputy Ministry for Mineral Resources, Ministry of Petroleum and Mineral Resources, Kingdom of Saudi Arabia. 44 p.

Janjou D., Halawani M.A., Brosse J.M., Al-Muallem M.S., Becq-Giraudon J.F., Dagain J., Genna A., Razin P., Roobol M.J., Shorbaji H. and Wyns R. (1997b) – Explanatory notes to the geologic map of the Tabuk quadrangle, Kingdom of Saudi Arabia. Geoscience Map GM-137, scale 1:250,000, sheet 28B. Deputy Ministry for Mineral Resources, Ministry of Petroleum and Mineral Resources, Kingdom of Saudi Arabia. 49 p.

Jones P.J and Stump T.E. (1999) – Depositional and tectonic setting of the Lower Silurian hydrocarbon source rock facies, central Saudi Arabia. AAPG Bulletin, vol. 83, n°2, February 1999, pp. 314-322.

Konert G., Afifi A.M., Al-Hajri S.A. and Droste H.J. (2001) - Paleozoic stratigraphy and hydrocarbon habitat of the Arabian Plate. GeoArabia, vol. 6, n° 3, pp. 407-442;

Le Nindre Y.M., Manivit J., Vaslet D., 1990 - Le Permo-Trias d'Arabie centrale. Histoire géologique de la bordure occidentale de la plate-forme arabe, vol. 3. Doc. BRGM n° 193. Editions du BRGM. ISSN.

Le Nindre Y.M., Vaslet D. and Manivit J. (1990) – Le Permo-Trias d’Arabie Centrale. Histoire géologique de la Plate-forme Arabe. Volume 3 Document du BRGM n°193. Editions BRGM, Orlméans, 1990. 290 p..

Le Nindre Y.M., Vaslet D., Maddah S., and Al-Husseini M. (in press) Sequence stratigraphy and paleoenvironments of the Biyadh Sandstone and Wasia Formation, Saudi Arabia. GeoArabia. Manama, Bahrain.

Lebret P., Halawani M., Memesh A., Razin P., Bourdillon C., Janjou D., Le Nindre Y.M, Roger J., Shorbaji H., and Kurdi H. (1999) - Geologic map of the Turubah quadrangle, sheet 28F, Kingdom of Saudi Arabia, scale 1:250,000. Geoscience Map GM-139. Explanatory notes to the Geologic map of the Turubah quadrangle, sheet 28F. 33 p., Kingdom of Saudi Arabia, Ministry of Petroleum and Mineral Resources, Directorate General of Mineral Resources. A.H. 1420 - A.D. 1999.

(Mahmoud M.D., Vaslet D., and Al-Husseini M.I. (1992) – The Lower Silurian Qalibah Formation of Saudi Arabia: an important hydrocarbon source rock. AAPG Bulletin, vol. 76, n°10, October 1992, pp 1491-1506, 12 figs.

Riddler G.P., Khallaf H.M., and Farasani A.M., 1983. Exploration for phosphate in the Sirhan-Turayf Region, northwest Saudi Arabia. Open File Report RF-OF-03-22. Ministry of Petroleum and Mineral Resources, DMMR, Jiddah, 1403AH. 12 p., 5 fig.

Sharland P.R., Casey D.M., Davies R.B., Simmons M.D. and Sutcliffe O.E. 2004. Arabian plate sequence stratigraphy, GeoArabia, vol.9, n°1, 2004, pp. 199-214.

Szabo F. and Kheradpir A. (1978) – Permian and Triassic stratigraphy, Zagros Basin, south-west Iran. Journal of Petroleum Geology, vol 1, n°2, pp 57-82.

Thomas H.J., Roger J., Halawani M., Memesh M., Lebret, P., Bourdillon C., Buffetaut E., Cappetta H., Cavelier C., Dutheil D., Tong H. and Vaslet D. 1999. Late Paleocene to early Eocene marine vertebrates from the uppermost Aruma Formation (northern Saudi Arabia): implications for the K-T transition. Comptes Rendus de l’Académie des Sciences, Paris, t.329, p.905-912.



Van Eck M., Riddler G.P., McHugh J.J. and Farasani A.M., 1984. Sirhan-Turayf phosphate project. The discovery of a significant phosphorite resource in the Al Jalamid area. Open File Report RF-OF-04-19. Ministry of Petroleum and Mineral Resources, DMMR, Jiddah, 1404AH. 30 p., 12 fig.

Vaslet et al. (in press) A set of papers in Stratigraphy of the Middle East Permian-Triassic Carbonate Reservoirs: Khuff Formation of Arabia and the Dalan and Kangan Formations of Iran GeoArabia Special Publication (in-progress)

Vaslet D., Le Nindre Y.-M., Vachard D., Crasquin-Soleau S., Broutin J., Halawani M. and Al-Husseini M.I. (2004) -. Stratigraphy of the central Saudi Arabian Khuff Formation. 6th Middle East Geosciences Conference, GEO 2004. GeoArabia, Abstract, v. 9, no. 1, p. 139.)

Vaslet D., Le Nindre Y.-M., Vachard D., Broutin J., Crasquin-Soleau S., Berthelin M., Gaillot J., Halawani M., and Al-Husseini M.I. (2005) -. The Permian-Triassic khuff Formation of Central saudi Arabia. GeoArabia, vol. 10, n°4, 2005, pp. 77134. Gulf PetroLink, Bahrain.

Wallace C.A., Dini S.M. and Al-Farasani A.A. (1998) – Geologic map of Ash Shuwayhitiyah quadrangle. Ministry of Petroleum and Mineral resources, Deputy Ministry for Mineral resources. A.H. 1418, A.D. 1998.

Wender L.E, Bryant J.W, Dickens M.F., Neville A.S, and Al-Moqbel A.S. (1998). Palaeozoic (Pre-Khuff) hydrocarbon geology of the Ghawar area, Eastern Saudi Arabia. GeoArabia, vol. 3, n°2, pp. 273-302.

Ziegler M.A. (2001) - Late Permian to Holocene paleofacies evolution of the Arabian plate and its Hydrocarbon occurrences. GeoArabia, vol 6, n° 3, 2001.pp 445-504.



PLATES

VOLUME 13

GEOLOGY



List of plates Plate 1 - Location Map










































































47

Plate 1 - Location Map

"

"

"

"

#

#

"

"

#

#

"

"

Wadi Sirhan

Wadi Ar Rumah

26°

30°

32°

28°

24°

40° 42° 44°38°36°

26°

30°

32°

28°

40° 42° 44°

24°38°36°

HailTabuk

Al Jawf

Northern Border

Al Qassim

Riyadh

Al Madinah

ARAR

HA'IL

BAQ'A

SAJIR

TAYMA

TABUK

AL'ULA

SAKAKA

UNAYZAH

BURAYDAH

AD DUWADIMI

AL QURAYYAT

§

0 100 20050

Kilometres

Legend" Major town

# Minor town

Road

An Nefud (sand dunes)

Province (Min. of Planning)


Enlarged area


48


"

"

"

"

#

#

"

"

#

#

"

"

Wadi Sirhan

Wadi Ar Rumah

26°

30°

32°

28°

24°

40° 42° 44°38°36°

26°

30°

32°

28°

40° 42° 44°

24°38°36°

Figure 8

Y = 800,000

X =

505,

000

X =

300,

000

ARAR

HA'IL

BAQ'A

SAJIR

TAYMA

TABUK

AL'ULA

SAKAKA

UNAYZAH

BURAYDAH

AD DUWADIMI

AL QURAYYAT

§

0 100 20050

Kilometres

Legend" Major town

# Minor town

Wadi Sirhan faults

Cross section Y = 800,000

Cross section X = 300,000

Cross section X = 505,000

Schematic cross section (fig. 8)


An Nefud (sand dunes)

Enlarged area


49


26°

30°

32°

28°

40° 42° 44°38°36°

26°

30°

32°

28°

40° 42° 44°38°36°

Qes

Ka

Dt

Ttm

Oss

Ss

TtjTQb

Qal

Sq Dt

TQb

Oss

Dj

CS

Tsh

Dt

OCq

Qal

OssQal

Ttj

Oqk

Ttm

Oss

TrPk

Trj

CS

Oss

Qdc

Qdc

§

0 100 20050

Kilometres

Enlarged area

LegendQs, Sabkhah deposits

Qes, Sand Dune

Qal, Alluvial deposit

Qsg, Sand and gravel deposit

Qdc, Calcareous duricrust

Ql, Lacustrine deposits

TQb, Harrat

Hbj, Harrat al Jadir

Ttj, Jalamid Formation

Ttm, Mira Formation

Tsh, Sirhan Formation

Ka, Aruma Formation

Kw, Wasia Formation

BX, Zabirah bauxite

Kb, Biyadh Formation

Jj, Jubaila Limestone

Jh, Hanifa Formation

Jtw, Tuwaiq mountain limestone

Jdu, Dhruma Formation

Jmu, Marrat Formation

Trm, Minjur Formation

Trj, Jilh Formation

Trs, Sudair Shale

TrPk, Khuff Formation

Dju, Jubah Formation

Dj, Jauf Formation

Dt, Tawil Formation

Ss, Sharawra Formation

Sq, Qusaiba Formation

Su, Uqlah Formation

SOs, Zarqa Formation, Sarah Formation

Oqq, Qasim Formation (Quwarah Member)

Oqr, Qasim Formation (Ra'an Member)

Oqk, Qasim Formation (Kahfah Member)

Oqh, Qasim Formation (Hanadir Member)

Oss, Saq Sandstone

CS, Siq Sandstone

OCq, Quweira Sandstone


50


Aquifers cross-section x=505,000

Pre-Qusaiba aquifers

Pre-Hercynian, post-Qusaiba aquifers

W. W. SirhanSirhan ((AzraqAzraq) ) grabengraben

Harrats

Late Cretaceous unconformity

(Qusaiba)





Harrats

Late Cretaceous unconformity

(Qusaiba)


51


Aquifers cross-section y=800,000


Pre-Hercynian, post-Qusaibaaquifers

Syn- & post-rift aquifers

Post -HercynianaquifersW. W. SirhanSirhan ((AzraqAzraq) )

grabengraben

Pre-Unayzahunconformity

(PUU)

(Qusaiba)

Aquifers cross-section y=800,000


Pre-Hercynian, post-Qusaibaaquifers

Syn- & post-rift aquifers

Post -HercynianaquifersW. W. SirhanSirhan ((AzraqAzraq) )

grabengrabenW. W. SirhanSirhan ((AzraqAzraq) )

grabengraben

Pre-Unayzahunconformity

(PUU)

(Qusaiba)


52




Syn- & post-rift aquifers Post -Hercynian

aquifers



(Qusaiba)



Syn- & post-rift aquifers Post -Hercynian

aquifers



(Qusaiba)


53


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

600 m

700 m

700 m

800 m

800 m

1400 m1300 m

Main cities














Top elevation of Harrats (m msl)

1700 to 18001600 to 17001500 to 16001400 to 15001300 to 14001200 to 13001100 to 12001000 to 1100900 to 1000800 - 900700 - 800600 - 700500 - 600


54


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

500 m

600

m

600 m

800 m700 m

900 m

800 m

1000

m

Main cities














Top elevation of Sand-dunes (m msl)

1300 to 14001200 to 13001100 to 12001000 to 1100900 to 1000800 - 900700 - 800600 - 700500 - 600400 - 500


55


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

550 m700 m

550 m

550

m

700 m

850

m 700 m

550 m

850 m

550 m

700 m

850 m

Main cities














Top elevation of Eoc-Maast (m msl)

1450 to 16001300 to 14501150 to 13001000 to 1150850 to 1000700 - 850550 - 700400 - 550250 - 400


56


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

600 m

400 m200 m400 m600 m600 m

200 m

400 m

600 m

0 m

200 m

600

m

-400 m

-600 m400 m

800 m600 m

1000 m

1200 m

Main cities














Top elevation of Cretac-early-mid (m msl)

1400 to 16001200 to 14001000 to 1200800 to 1000600 to 800400 - 600200 - 400

0 - 200-200 - 0-400 - -200-600 - -400-800 - -600

-1000 to -800


57


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

-600 m

-400 m-200 m

0 m200 m

400 m600 m

-400 m

Main cities











JubbahJubbahJubbahJubbahJubbahJubbahJubbahJubbahJubbahBaq'aBaq'aBaq'aBaq'aBaq'aBaq'aBaq'aBaq'aBaq'a


Top elevation of Hith-Gotnia (m msl)

600 - 800400 - 600

0 to 2500 - 200

-200 - 0-400 - -200-600 - -400-800 - -600


58


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

-250 m-500 m

250 m500 m

0 m

250 m

500 m

-250 m

0 m

-1500 m

-1250 m

-1000 m

-500 m

250 m500 m

-250 m

250 m500 m

0 m

Main cities














Top elevation of Trias-Jurassic (m msl)

750 to 1000500 - 750250 - 500

0 - 250-250 to 0-500 - -250-750 - -500

-1000 to -750-1250 to -1000-1500 to -1250-1750 to -1500-2000 to -1750


59


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

600

m

600 m

600 m

800 m

600 m60

0 m

1000 m

800

m

800 m

800 m

600 m

600 m

600 m

800 m

1400 m

800 m

1200 m

Main cities














Top elevation of STQ complex (m msl)

1600 to 18001400 to 16001200 to 14001000 to 1200800 to 1000600 - 800400 - 600200 - 400

0 - 200-200 - 0-420 - -200


60


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

0 m-500 m

-2000 m

-1500 m

-1000 m

0 m

500 m

-500 m

500 m

0 m

-500 m

-1000 m

0 m

-500 m

Main cities














Top elevation of Sudair (m msl)

500 to 10000 - 500

-500 - 0-1000 to -500-1500 to -1000-2000 to -1500-2500 to -2000-3000 to -2500


61


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

500 m

0 m

-1000 m

-2000 m

-2500 m

-1500 m-500 m

0 m

500 m-1000 m

0 m -500 m

500 m

-500 m0 m

-500 m

-500 m

0 m

Main cities








BuraydahBuraydahBuraydahBuraydahBuraydahBuraydahBuraydahBuraydahBuraydahUnayzahUnayzahUnayzahUnayzahUnayzahUnayzahUnayzahUnayzahUnayzah






Top elevation of Khuff (m msl)

500 to 10000 - 500

-500 - 0-1000 to -500-1500 to -1000-2000 to -1500-2500 to -2000-3000 to -2500


62


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

-2500 m

-2000 m-1500 m

0 m500 m

0 m

-1000 m-500 m

500 m-500 m0 m

-1500 m

-1000 m

-500 m

0 m

-500

m

-500 m

-500 m

-2500 m-1500 m

Main cities






Daw mat-al-JandalDaw mat-al-JandalDaw mat-al-JandalDaw mat-al-JandalDaw mat-al-JandalDaw mat-al-JandalDaw mat-al-JandalDaw mat-al-JandalDaw mat-al-JandalSakakahSakakahSakakahSakakahSakakahSakakahSakakahSakakahSakakah



UnayzahUnayzahUnayzahUnayzahUnayzahUnayzahUnayzahUnayzahUnayzah

BuraydahBuraydahBuraydahBuraydahBuraydahBuraydahBuraydahBuraydahBuraydah




Top elevation of Ash Shiqqah (m msl)

500 to 10000 - 500

-500 - 0-1000 to -500-1500 to -1000-2000 to -1500-2500 to -2000-3000 to -2500


63


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

-1500 m

500 m

-2500 m

-2000 m

-500 m-1000 m

0 m

-500 m

-1000 m

Main cities













Top elevation of Unayzah (m msl)

500 to 10000 - 500

-500 - 0-1000 to -500-1500 to -1000-2000 to -1500-2500 to -2000-3000 to -2500


64


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas

Model extent


-500 m

500 m

-500 m

0 m

-500 m -1000 m

0 m

500

mMain cities AL UlaAL UlaAL UlaAL UlaAL UlaAL UlaAL UlaAL UlaAL Ula

Ha'ilHa'ilHa'ilHa'ilHa'ilHa'ilHa'ilHa'ilHa'ilTaymaTaymaTaymaTaymaTaymaTaymaTaymaTaymaTayma











Top elevation of Berwath (m msl)

500 to 10000 - 500

-500 - 0-1000 to -500-1500 to -1000


65


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

500 m

0 m

-500 m

0 m-1000 m

500 m

-500 m

0 m

0 m50

0 m

500 m500 m

Main cities




SakakahSakakahSakakahSakakahSakakahSakakahSakakahSakakahSakakahDaw mat-al-JandalDaw mat-al-JandalDaw mat-al-JandalDaw mat-al-JandalDaw mat-al-JandalDaw mat-al-JandalDaw mat-al-JandalDaw mat-al-JandalDaw mat-al-Jandal









Top elevation of Jubah (m msl)

500 to 10000 - 500

-500 - 0-1000 to -500-1500 to -1000


66


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

500 m

0 m

-500 m

-1000 m

0 m

500 m

-1000 m

-500 m

0 m-500 m

500 m

-500 m

0 m

0 m

500 m

500 m

500 m

500 m

Main cities













Top elevation of Jauf (m msl)

500 to 10000 - 500

-500 - 0-1000 to -500-1500 to -1000-2000 to -1500


67


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

0 m

-500 m

500 m

1000 m

0 m

-500 m

-1000 m

500 m

0 m

-1500 m

-1000 m

-500 m

500 m

0 m

-2000 m

-500 m-1000 m-1500 m

-1500 m

-1000 m

-2000 m

0 m

500 m

-1500 m-2000 m

0 m

-500 m

0 m

-500 m-1000 m

500 m0 m

-500 m0 m

500 m0 m

0 m

500

m

500 m

1000 m

1000

m

5 00 m

500 m

1000 m

1000 m

1000 m

500 m 500 m

1000 m 1000 m

1000

m

Main cities














Top elevation of Tawil (m msl)

1000 to 1500500 to 1000

0 - 500-500 - 0

-1000 to -500-1500 to -1000-2000 to -1500-2500 to -2000-3000 to -2500


68


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

-1000 m-500 m

0 m

-1500 m

-500 m

500 m

-1000 m

0 m

-2500 m

-2000 m

-1500 m

-2500 m

-2000 m

-500 m0 m

500 m

-1000 m

0 m

500

m

-500 m

0 m

-1500 m

-1000 m

-500 m

0 m

500 m

-1500 m

0 m

0 m

500 m

1000 m

0 m500 m1000 m

-1000 m

-500 m

0 m

500 m

1000 m

Main cities














Top elevation of Sharawra (m msl)

1000 to 1500500 to 1000

0 - 500-500 - 0

-1000 to -500-1500 to -1000-2000 to -1500-2500 to -2000-3000 to -2500


69


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

-3000 m

-1500 m

-500 m

0 m

-1000 m-500 m

0 m

500 m

-2500 m

-2000 m

-1500 m-1000 m

-3500 m

500 m

-300

0 m

0 m0 m

-1500 m-2000 m- 250 0 m

-1000 m

-500 m

-500 m

-500 m

0 m

0 m

500 m

500 m

0 m

-500 m

0 m500 m

0 m

Main cities














Top elevation of Qusaiba (m amsl)

1000 to 1500500 to 1000

0 - 500-500 - 0

-1000 to -500-1500 to -1000-2000 to -1500-2500 to -2000-3000 to -2500-3500 to -3000-4000 to -3500


70


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

500 m

-1500 m

-1000 m-500 m0 m500 m

-1500 m-1000 m-500 m

0 m

-450

0 m

-2500 m-2000 m

-3500 m

500 m

-400

0 m

-35 00 m

-3000 m

-2500 m

-2000 m

-1500 m

0 m

500 m

-500 m

-500 m-1000 m

-1500 m

0 m

500 m

-1000 m

-500 m

0 m

Main cities














Top elevation of Quwarah-Sarah (m msl)

1000 to 1500500 to 1000

0 - 500-500 - 0



71


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

-2000 m

0 m

-1000 m

500 m

-1500 m

-3000 m

-1000 m0 m

-500 m0 m

500 m

-450

0 m

-1500 m

-2500 m-2000 m

-500 m

-3500 m

-1000 m

-1500 m-2000 m

-400

0 m

-3000 m

-2500 m

-150

0 m

0 m

500 m

-500 m

-1000 m

-2000 m

0 m

-500 m

-1000 m

500 m

-500 m

Main cities














Top elevation of Raan (m amsl)

1000 to 1500500 to 1000

0 - 500-500 - 0

-1000 to -500-1500 to -1000-2000 to -1500-2500 to -2000-3000 to -2500-3500 to -3000-4000 to -3500-4500 to -4000-5000 to -4500-5500 to -5000


72


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

-2000 m

-1000 m

-500 m

0 m

500 m

-1500 m-1000 m

-500 m0 m

-2000 m

500 m

-3000 m

-450

0 m

0 m

-2500 m

-1500 m

-500 m

-1000 m

-2000 m

-400

0 m

-3500 m

-3000 m

-2500 m

-2000 m

0 m

500 m

-500 m

-150

0 m

-1500 m

-1000 m

-500 m

500 m

0 m

-1000 m

-500 m

Main cities














Top elevation of Kahfah (m msl)

1000 to 1500500 to 1000

0 - 500-500 - 0

-1000 to -500-1500 to -1000-2000 to -1500-2500 to -2000-3000 to -2500-3500 to -3000-4000 to -3500-4500 to -4000-5000 to -4500-5500 to -5000


73


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

500 m-2000 m

-1500 m-1000 m-500 m0 m

0 m

500 m

-3000 m-2500 m-2000 m

-450

0 m

-5000 m

0 m

-500 m

-1500 m-1000 m

500 m

0 m

-400

0 m

-3500 m

-3000 m

-2500 m

-2500 m

-2000 m

-2000 m

-500 m

-1500 m

-500 m

-1000 m

-1500 m

0 m

500 m

-1000 m

-500 m

0 m500 m

Main cities








AL UlaAL UlaAL UlaAL UlaAL UlaAL UlaAL UlaAL UlaAL UlaUnayzahUnayzahUnayzahUnayzahUnayzahUnayzahUnayzahUnayzahUnayzahBuraydahBuraydahBuraydahBuraydahBuraydahBuraydahBuraydahBuraydahBuraydah





Top elevation of Hanadir (m msl)

1000 to 1500500 to 1000

0 - 500-500 - 0



74


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

-1000 m-1500 m

-500 m0 m

500 m

-1000 m-500 m0 m

-2000 m

500 m

-2500 m

-1500 m-500 m

-3000 m

-1000 m

0 m

-500

0 m

-2000 m

500 m

-500 m

0 m500 m1000 m

500 m 0 m

-2500 m

-3000 m

-1500 m

-200

0 m

-450

0 m

-4000 m

-3500 m

-500 m

-1500 m

-2500 m

-1000 m

0 m

-1500 m

-1000 m-500

m

-500 m

Main cities














Top elevation of Saq (m msl)

1000 to 1600500 to 1000

0 - 500-500 - 0



75


N

200100

kilometre

Contourlines

500

-500 m


Model extent

-800

-7200-8000

-5600

-4000

-800

0

-7200

-4000

-2400

-2400

-800

-800

-800

800

-5600

-5600

800

-5600

-5600

-5600

-4000

-4000

-240

0

-800

-4000

-4000

-2400

-2400

-800

800

-4000-5600

-800

Main irrigatedareas

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main cities














Bottom elevation of Saq (m msl)

800 - 1 6000 - 800

-800 - 0-1 600 - -800-2 400 - -1 600-3 200 - -2 400-4 000 - -3 200-4 800 - -4 000-5 600 - -4 800-6 400 - -5 600-7 200 - -6 400-8 000 - -7 200


76


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

100 m

50 m

150 m

100 m

50 m

250 m

200 m

150 m

150 m

Main cities













Thickness of Harrats (m)

0 - 5050 - 100

100 - 150150 - 200200 - 250250 - 300300 - 350350 - 400


77


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

50 m

50 m

150 m

100 m100 m

150 m

50 m

50 m

100 m

50 m

50 m

50 m

Main cities



TaymaTaymaTaymaTaymaTaymaTaymaTaymaTaymaTayma Ha'ilHa'ilHa'ilHa'ilHa'ilHa'ilHa'ilHa'ilHa'il









Thickness of Sand-dunes (m)

0 - 5050 - 100

100 - 150150 - 200200 - 250


78


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

125 m

125 m

250 m

375 m125 m

125 m

250 m

375 m

250 m

125 m

125 m

125 m

250

m

250 m

375

m

375 m

500 m1000 m

1125 m

125 m

125 m

500 m

250 m

375 m

Main cities














Thickness of Eoc-Maastrichtian (m)

0 - 125125 - 250250 - 375375 - 500500 - 625625 - 750750 - 875875 - 1 000

1000 to 11251125 to 12501250 to 1375


79


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

250 m500 m

625 m750 m125 m

250 m375 m

125 m

375 m

125 m250 m

500

m

625

m

375 m

500 m

625

m 750 m

375

m125 m

250

m

125

m

250

m

875 m

1000 m

125 m

125 m

250 m

750 m

250 m

375

m

375 m

500 m

500 m

625 m

625 m

375 m

625 m

125 m

625

m500 m

Main cities













Thickness of Cretaceous early-mid (m)

0 - 125125 - 250250 - 375375 - 500500 - 625625 - 750750 - 875875 to 1000

1000 to 1125


80


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

200 m

300 m

100 m

200

m20

0 m

100

m

100 m

Main cities













Thickness of Hith_Gotnia (m)

0 - 100100 - 200200 - 300300 - 400400 - 500


81


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

1350 m1050 m

450 m750 m

1050

m

1200

m13

50 m

1650 m

300 m600 m

900 m

450

m

150 m300 m

150 m

150

m

300 m

300

m

450 m

450 m

600 m

150

m

300

m30

0 m

450

m

450

m

600 m

Main cities














Thickness of Trias-Jurassic (m)

0 - 150150 - 300300 - 450450 - 600600 - 750750 - 900900 to 1050

1050 to 12001200 to 13501350 to 15001500 to 16501650 to 18001800 to 19501950 to 2100


82


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

1200 m900 m1500 m

1800 m2100 m

300 m600 m

2400 m

1500 m900 m

1200 m

300 m600 m

300 m

600 m

900 m

600 m300 m

300 m60

0 m

900 m

300

m

600

m

3000 m1800 m

300 m

600 m

900 m

900 m1200 m

1500 m

1200 m

1200

m

900 m

Main cities














Thickness of STQ (m)

0 - 300300 - 600600 - 900900 to 1200

1200 to 15001500 to 18001800 to 21002100 to 24002400 to 27002700 to 30003000 to 33003300 to 3600


83


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

250 m300 m

100 m

200 m250 m

250 m

300 m

150 m

100 m

50 m100 m

150 m

200

m

50 m

200 m

150 m

50 m

100 m

200 m250 m

150 m250 m

100 m

150 m

200

m

200 m

250 m

250 m

300 m

350 m

50 m

400

m450

m50

0 m

100

m

300 m

Main cities BuraydahBuraydahBuraydahBuraydahBuraydahBuraydahBuraydahBuraydahBuraydahUnayzahUnayzahUnayzahUnayzahUnayzahUnayzahUnayzahUnayzahUnayzah









Al Qurayyat



Thickness of Sudair (m)

0 - 5050 - 100

100 - 150150 - 200200 - 250250 - 300300 - 350350 - 400400 - 450450 - 500500 - 550550 - 600


84


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

400 m

250 m

300 m

350 m

50 m

150 m

350

m

300 m350 m

50 m

200 m250 m

300 m

100 m200 m

50 m 15

0 m

50 m

100

m

100 m

150 m

50 m

100 m50 m

50 m

50 mMain cities














Thickness of Khuff (m)

0 - 5050 - 100

100 - 150150 - 200200 - 250250 - 300300 - 350350 - 400400 - 450


85


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

50 m

50 m

100 m

2 00

m

150

m

300 m

500 m

200 m50

m

250 m

100

m

50 m

150

m

50 m

50 m

150 m

50 m10

0 m

50 m

50 m

Main cities














Thickness of Ash Shiqqah (m)

0 - 5050 - 100

100 - 150150 - 200200 - 250250 - 300300 - 350350 - 400400 - 450450 - 500500 - 550550 - 600600 - 650650 700


86


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

100 m

50 m

100 m50 m

50 m100 m

150 m

50 m

Main cities














Thickness of Unayzah (m)

0 - 5050 - 100

100 - 150150 - 200200 - 250250 - 300300 - 350


87


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

150 m

250 m

350 m

150 m

50 m

350 m

200 m100 m50 m

150 m

100

m200

m

50 m

150 m

100 m

100 m

50 m

50 m

50 m50 m

200 m250 m

Main cities













Thickness of Berwath (m)

0 - 5050 - 100

100 - 150150 - 200200 - 250250 - 300300 - 350350 - 400400 - 450450 - 500500 - 550


88


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

125 m

125 m

250 m

375 m

125 m

250 m

250

m375 m

250

m12

5 m

125 m

375 m

625 m

1000 m

875 m

500 m

1375

m

1500 m

875 m 1125 m

625 m

500

m

375 m

250 m

Main cities














Thickness of Jubah (m)

0 - 125125 - 250250 - 375375 - 500500 - 625625 - 750750 - 875875 to 1000

1000 to 11251125 to 12501250 to 13751375 to 15001500 to 1625


89


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas

Model extent


125

m375 m

250 m

625 m

500 m

250 m

750 m

500 m

625 m

375 m125 m

250 m

750 m

1000

m

1250 m

750 m

875 m

625 m

875

m11

25 m

625

m

125

m

250 m

375

m

Main cities














Thickness of Jauf (m)

0 - 125125 - 250250 - 375375 - 500500 - 625625 - 750750 - 875875 to 1000

1000 to 11251125 to 12501250 to 13751375 to 15001500 to 1625


90


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

125 m

250 m

125 m

125 m

250 m

125 m

375 m

375 m

375 m

500 m

250 m 375 m

375 m

375 m

375 m

500 m

500 m

125 m

125

m37

5 m50

0 m

625 m

750 m

125 m250 m

125 m

250 m

375 m

500 m625 m

625 m

750 m

750 m

875 m

250 m

125 m250 m

250 m

625

m

375 m

1000 m

125 m

500 m

500 m

Main cities














Thickness of Tawil (m)

0 - 125125 - 250250 - 375375 - 500500 - 625625 - 750750 - 875875 - 1 000

1000 to 11251125 to 1250


91


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

125

m

125 m

250 m125 m

250 m

375

m

375 m

250 m

625 m

500 m

625 m

750 m

875

m

1000

m

1125

m

375 m125 m

250 m

125 m

250 m

375 m

500 m

625 m

750 m

875 m

250 m

500 m

1125 m

125

m

1000 m

375

m

375 m

250 m

250

m

375 m

375 m

1250 m

500 m

375

m

500 m

500 m750 m

875 m

125

m500 m

625 m

375 m

250 m

250 m

250 m

375 m

375 m

750 m500 m

625 m

125 m250 m

250

m

375 m

500

m

125 m

500 m

125 m

250 m

250 m250 m

375 m

500 m

625 m125 m

Main cities














Thickness of Sharawra (m)

0 - 125125 - 250250 - 375375 - 500500 - 625625 - 750750 - 875875 to 1000

1000 to 11251125 to 12501250 to 13751375 to 15001500 to 16251625 to 1750


92


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

200 m

200 m

200 m

400 m

600 m800 m1000 m12

00 m

200 m

400 m

1000 m

1400

m

400 m

200 m

400 m

800 m

600 m

1200 m

1800 m

1400

m

1600

m

1600 m1200 m

800

m12

00 m

1400 m

1600

m

400 m

200

m

400 m

400

m

200 m

200 m

200 m

Main cities














Thickness of Qusaiba (m)

0 - 200200 - 400400 - 600600 - 800800 to 1000

1000 to 12001200 to 14001400 to 16001600 to 18001800 to 2000


93


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

50 m100 m150 m

50 m

100 m

150 m

100 m150 m

50 m

150 m100 m

150

m20

0 m

100 m

150 m

100 m

200 m

150 m

50 m

200 m

100 m

150 m

250 m

200 m50 m

100 m

150

m150

m

200 m

100

m

100

m

100 m

100 m

150 m 200 m

150 m100

m

100 m

150

m

150 m

200 m

Main cities













Thickness of Quwarah-Sarah (m)

0 - 5050 - 100

100 - 150150 - 200200 - 250250 - 300300 - 350350 - 400


94


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

50 m

100 m

200

m

150 m

50 m50 m

100

m

50 m

50 m

50 m

50 m

50 m

50 m

50 m

50 m

50 m

100 m

50 m

50 m

50 m

50 m100 m

Main cities














Thickness of Raan (m)

0 - 5050 - 100

100 - 150150 - 200200 - 250250 - 300300 - 350350 - 400


95


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

100 m100 m

200

m10

0 m

150

m

50 m100 m

200 m250 m

50 m200 m

150 m

150 m

100 m200 m

200 m50 m 150 m

200

m25

0 m300 m

250 m

200 m

100 m

350 m

200

m

200 m

150 m

200 m

250 m

300 m

150 m

150 m

150 m

150 m30

0 m

50 m

250 m

250 m

350 m

100 m

150

m

200 m

50 m100 m

100 m

150 m

200 m

100 m200 m

50 m

100 m

Main cities














Thickness of Kahfah (m)

0 - 5050 - 100

100 - 150150 - 200200 - 250250 - 300300 - 350350 - 400400 - 450


96


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

50 m

50 m

50 m

50 m100 m

150 m

200 m

250

m

250 m

100 m150 m

200 m

300 m

300 m

350 m

350 m

50 m

100 m

150 m

200 m

50 m

Main cities














Thickness of Hanadir (m)

0 - 5050 - 100

100 - 150150 - 200200 - 250250 - 300300 - 350350 - 400400 - 450450 - 500


97


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

600 m

1500

m

600 m600 m

1200

m

1200 m

1200 m

2100 m

1500 m1800 m

2100 m

2400 m

2400

m

2400 m 3000 m

3000 m

3000 m

2400 m

2100 m

2100

m

1800 m

600

m

1200 m

1200

m

1500 m

1500

m

1800

m

1800

m

2400 m

3000 m

600 m

Main cities













Thickness of Saq (m)

0 - 300300 - 600600 - 900900 to 1200

1200 to 15001500 to 18001800 to 21002100 to 24002400 to 27002700 to 30003000 to 33003300 to 3600


98


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

50 m100 m

100 m

50 m

50 m

150 m

250 m

Main cities













Depth to Top of Eocene-Maastrichtian (m bgl)

Outcrop0 to 50

50 - 100100 - 150150 - 200200 - 250250 - 300


99


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

200 m

200 m

400 m

400

m200 m

400 m

1400 m

200 m200 m

1200 m

400 m

1000 m

400 m

Main cities













Depth to Top of early-mid-Cretaceous (m bgl)

Outcrop0 to 200

200 - 400400 - 600600 - 800800 - 1 000

1000 to 12001200 to 14001200 to 1400


100


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

1000 m

800 m

200 m400 m

600 m

Main cities














Depth to Top of Hith_Gotnia (m bgl)

Outcrop0 to 200

200 - 400400 - 600600 - 800800 - 1 000

1000 to 1200


101


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

250 m500 m

750 m1000 m

750 m250 m500 m

750 m

2250 m2000 m

250 m

500 m

1000 m 1500 m

1750 m

750 m

Main cities














Depth to Top of Trias_Jurassic (m bgl)

Outcrop0 to 250

250 - 500500 - 750750 to 1000

1000 to 12501250 to 15001500 to 17501750 to 20002000 to 22502250 to 2500


102


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

400 m800 m

2000 m2400 m

1200 m1600 m

1200 m

400 m800 m

800 m400 m

800

m

800 m

1600 m2800 m

1200 m

Main cities














Depth to Top of Sudair (m bgl)

Outcrop0 - 400

400 - 800800 to 1200

1200 to 16001600 to 20002000 to 24002400 to 28002800 to 32003200 to 3600


103


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

1200 m2000 m1600 m

0 m400 m

800 m2400 m

2800 m

0 m400 m

800 m1200 m

1600 m

0 m400 m

800 m1200 m

800 m

1200 m

800 m

1200 m

Main cities














Depth to Top of Khuff (m bgl)

Outcrop0 - 400

400 - 800800 to 1200

1200 to 16001600 to 20002000 to 24002400 to 28002800 to 32003200 to 3600


104


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

2400 m1200 m

800 m400 m2800 m

2000 m2400 m

3200 m

1600 m

800 m1200 m

400 m

1200 m

800 m

1200 m

Main cities















Depth to Top of Ash Shiqqah (m bgl)

0 - 400400 - 800800 to 1200

1200 to 16001600 to 20002000 to 24002400 to 28002800 to 32003200 to 36003600 to 4000


105


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

2800 m

2400 m3200 m

1200 m

800 m400 m

1200 m800 m

Main cities














Depth to Top of Unayzah (m bgl)

0 - 400400 - 800800 to 1200

1200 to 16001600 to 20002000 to 24002400 to 28002800 to 32003200 to 3600


106


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

1400 m1200 m800 m

1000 m

200 m

400 m

600 m

800 m

1000 m

1200 m

1400 m1600 m

1000

m

1200 m

800

m400

m60

0 m

200 m

Main cities














Depth to Top of Berwath (m bgl)

0 - 200200 - 400400 - 600600 - 800800 to 1000

1000 to 12001200 to 14001400 to 16001600 to 1800


107


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

200 m

400 m

1000 m

600 m800 m

1200 m

200 m

1400 m

400 m

800 m

1000 m

1200 m

200 m

400 m600 m200 m

200 m

1600 m

800

m

400 m

200 m

200 m

Main cities













Depth to Top of Jubah (m bgl)

Outcrop0 - 200

200 - 400400 - 600600 - 800800 to 1000

1000 to 12001200 to 14001400 to 16001600 to 18001 800 to 2 000


108


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

200 m400 m

600 m800 m

1000 m1200 m

1400 m

200 m0 m

800 m600 m

1800 m

1000 m

1400 m

1600 m

1200 m14

00 m

200 m

400 m

200 m

600 m

1000 m

Main cities






Daw mat-al_JandalDaw mat-al_JandalDaw mat-al_JandalDaw mat-al_JandalDaw mat-al_JandalDaw mat-al_JandalDaw mat-al_JandalDaw mat-al_JandalDaw mat-al_Jandal








Depth to Top of Jauf (m bgl)

Outcrop0 - 200

200 - 400400 - 600600 - 800800 to 1000

1000 to 12001200 to 14001400 to 16001600 to 18001 800 to 2 000


109


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

800 m1200 m

400 m

1600 m

800 m

1200 m

2000 m

400 m

2400 m

2800 m

2000 m

1600 m

2000 m

1200 m

1200 m

800 m

1600 m2400 m

400 m

800 m

800

m

400 m

400 m

400 m

0 m

0 m

0 m

0 m

400 m

0 m

0 m

400 m

Main citiesMain citiesMain citiesMain citiesMain citiesMain citiesMain citiesMain citiesMain cities














Depth to Top of Tawil (m bgl)

Outcrop0 - 400

400 - 800800 to 1200

1200 to 16001600 to 20002000 to 24002400 to 2800


110


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

1200 m1600 m

400 m 800

m

800 m

1200 m

2000 m

2400 m

400 m

2000 m

1600 m800 m

2400 m

2800 m

3200 m

3200 m

1200 m

400 m

2000 m1600 m

1200

m

2800 m

1600 m

1200 m400 m

400

m

400 m

400 m800 m

800

m

800 m

800 m

2000 m

400 m

800

m

1200 m

1600 m

2400 m

0 m

0 m

800 m

400 m0 m

800 m

0 m

400 m

Main cities














Depth to Top of Sharawra (m bgl)

Outcrop0 - 400

400 - 800800 to 1200

1200 to 16001600 to 20002000 to 24002400 to 28002800 to 32003200 to 3600


111


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

3200

m2000

m

1200 m

1600

m800 m400 m

1600 m20

00 m24

00 m

1200 m800 m

2800 m

400 m

2400 m

3200 m

3600 m

4000 m

2000 m1200 m

1600 m

2800 m

3200 m

1600

m

4000 m

4400 m

1200 m

1200 m

1600 m

1600 m

2000 m2400 m

800 m

400

m 800 m

800 m

400 m

2400 m

1200

m1200

m

3600 m

800 m

1600 m

0 m

400 m

1200 m

800 m

Main cities














Depth to Top of Qusaiba (m bgl)

Outcrop0 - 400

400 - 800800 to 1200

1200 to 16001600 to 20002000 to 24002400 to 28002800 to 32003200 to 36003600 to 40004000 to 44004400 to 4800


112


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

0 m

1500 m

2000 m1000 m

500 m2000 m

2500 m

0 m

1000 m

1500 m

3000 m

3500 m

500 m

2000 m

2500 m

4500 m

3000 m

4000 m

5000 m

5500 m

1500 m

5000 m

3500 m2000 m

2500 m

2500 m

3000

m

3500 m

2000 m

1500 m

2000 m

2000 m

3000 m3500 m

4000 m4500 m

1500 m

1500 m

2000 m

1000 m

1500

m

500 m500 m

1000 m

1000 m

500 m

Main cities














Depth to Top of Quwarah-Sarah (m bgl)

Outcrop0 - 500

500 to 10001000 to 15001500 to 20002000 to 25002500 to 30003000 to 35003500 to 40004000 to 45004500 to 50005000 to 55005500 to 6000


113


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

2000 m

1500 m

2500 m

500 m

1000 m

3000 m

2000 m

2500 m

500 m

1500 m

4500 m

4000 m

3500 m

1000 m

3000 m

2000 m

2500 m

5500 m

5000 m

3500 m

5000 m

1500 m

500 m

1000 m

1500 m2000 m

2500 m

2500 m

2500 m

1500

m

500 m

3000 m

3000 m

3500 m

3500 m 4000 m4500 m

5000

m

1500 m

2000 m

1500

m

2000

m

1000 m

4000 m

500 m

1500 m

1000 m

Main cities














Depth to Top of Raan (m bgl)

Outcrop0 - 500



114


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

2500 m

500 m2000 m1000 m

1500 m3000 m

2500 m

500 m

2000 m

4000 m

3500 m

4500 m

2500 m

5000 m

5500 m

1000 m

1500 m

2500 m

3000 m

1500 m2000 m

3000 m

3500 m

2000 m

1500

m4000 m

2000 m

500 m

Main cities















Depth to Top of Kahfah (m bgl)

Outcrop0 - 500



115


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

500 m2500 m

2000 m

1000 m1500 m

2500 m

500 m2000 m

3000 m3500 m

1000 m

1500 m500 m

2500 m

5000 m

4000 m

4500 m

3000 m

3500 m

2500 m

5500 m

2000 m1500 m

5500 m

1000 m

500 m

3500 m

2000 m

2500 m

3000 m

3000 m

1500 m

2500 m

4000 m

4000 m

4000 m

4500 m

5000

m

2500 m

1500 m

2000

m

2000 m

1000 m

3500 m

1000 m

1500 m

500 m

2000 m500 m

Main cities














Depth to Top of Hanadir (m bgl)

Outcrop0 - 500



116


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

1500 m2000 m

2500 m500 m

1000 m

2500 m

500 m1000 m

1500 m2000 m

2500 m

2000 m

500 m

1000 m1500 m

4000 m

3000 m3500 m

4500 m

2500 m

5000 m

2000 m

500 m

5500 m

5500 m

3500 m6000 m

3000 m

2000 m

2500 m

3000 m

3000 m

5000

m3500 m

3500 m

4000 m

4000 m

4500 m

1500 m

2500 m

2000

m

2500 m

4000 m

2000 m

1000 m

500 m

1500 m

1500 m

500 m

1000 m

0 m

1500 m

1000 m

500 m

Main cities AL UlaAL UlaAL UlaAL UlaAL UlaAL UlaAL UlaAL UlaAL Ula













Depth to Top of Saq (m bgl)

Outcrop0 - 500

500 to 10001000 to 15001500 to 20002000 to 25002500 to 30003000 to 35003500 to 40004000 to 45004500 to 50005000 to 55005500 to 60006000 to 6500


117


N

200100

kilometre

Contourlines

500

-500 m

48° 44° 46°

26°

46° 42° 44°

48°

24°

32°

30°

28°

24°

42°

30°

28°

26°

40° 38° 34°

40° 36° 34° 38°

32° 36°

Main irrigatedareas


Model extent

1200

1200

2400

3600

4800 4800

2400

3600

3600

1200

4800

3600

1200

2400

3600

3600

60004800

1200

6000

4800

7200

6000

6000

7200

12002400

2400

6000

84008400

4800

6000

2400

Main cities














Depth to bottom of Saq (m bgl)

9 000 - 9 6008 400 - 9 0007 800 - 8 4007 200 - 7 8006 600 - 7 2006 000 - 6 6005 400 - 6 0004 800 - 5 4004 200 - 4 8003 600 - 4 2003 000 - 3 6002 400 - 3 0001 800 - 2 4001 200 - 1 800

600 - 1 2000 600

Date post:	15-Nov-2014
Category:	Documents
Upload:	izrarahmed
View:	132 times
Download:	7 times

FR Vol 13 Geology

Documents