Arabian Plate Chronostratigrahic Maps

Chronostratigraphic Isopach Chronostratigraphic Isopach

mapping of sequences of the mapping of sequences of the

Arabian Plate: Product and Arabian Plate: Product and

ProcessProcess

By Walter H. Pierce

And

Everett Rutherford

Of

STARTEXPOctober 2009

• StartExp is a group of independent consultants with more than 80 years of combined hydrocarbon exploration and production experience. We have worked in most parts of the world, with particular emphasis on Africa, the Middle East and Central Asia.

• We provide products and consulting services that form an integrated technical framework for improving decision making in selecting acreage for hydrocarbon exploration. While our current databases and initiatives are not designed for the individual prospect scale, our methods are scale-independent and can be applied on whatever level available data allows.

• Our principal tools include potential fields data, remote images, surface geology, basin modeling, and a variety of in-house regional surface and subsurface data sets. Additional data may be contributed by the client. All project elements are assembled in a GIS framework designed to assist exploration ventures.

• For more information please visit: http://startexp.com/

STARTEXP

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Walter H. Pierce and Everett Rutherford

Problems and Talk ObjectivesProblems and Talk Objectives

• Point out selected new discoveries in stratigraphic context

• Mapping across nomenclature changes and country

boundaries.

• Mapping chronostratigraphic sequences versus

Formations.

• Pay attention to zero-edge accuracy

– maps will be used for sub crop, worm’s eye, subsidence

• Process that is updateable and adaptable.

• Show process and “bag of tricksbag of tricks.”

• Show products

STARTEXP

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Talk OrganizationTalk Organization• Preliminary View of Products

• Scale and Database

• Surface Geology Constraint

• Queries

– wells spudding in sub crop (RedRed)

– wells with interval missing in subsurface (White)

– Wells with thicknesses (Black)

– Wells with penetrations (Gray and Yellow)

• Construction of Composite Table for Mapping

• Quality Control

• Review of Products and importance of specific maps

STARTEXP

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Comparison of scaleComparison of scale

of Arabian Plateof Arabian Plate

versusversus

lower 48lower 48

STARTEXP

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STARTEXP

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Map distribution

Of

Database

DatabaseDatabase

• 2819 wells

– mappable

– 2 or more tops in well

• 46,911 tops records

– mappable

• 481 unique ages

• ~ 600 unique lithostratigraphic units.

STARTEXP

http://Startexp.com


Assigning Ages to TopsAssigning Ages to Tops

• The process begins with assigning a 9 digit code

to stratigraphic names.

– Attempt to have the code relate to age and superposition.

• A spreadsheet - database cycle focuses on

code superposition problems.

• Repeat cycle, adjust, repeat .. And so on... until

codes obey superposition.

• Finally 9 digit codes are converted to absolute

ages.

STARTEXP

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A B C D E FWell Formation Depth Sequence Shifted Subtract

Code Sequence E from D

Code

1 Dukhan 1 Dammam 0 201000000

2 Dukhan 1 Umm Er Raduma 300 202000000 201000000 1000000

3 Dukhan 1 Simsima 500 301000000 202000000 99000000

4 Dukhan 1 Mishrif 1000 304000000 301000000 3000000

5 Dukhan 1 Ahmadi 2000 305000000 304000000 1000000

6 Dukhan 1 Nahr Umr 4000 307000000 305000000 2000000

7 Dukhan 1 Shuaiba 4500 401000000 307000000 94000000

8 Dammam 1 Rus 0 203000000 401000000 -198000000

9 Dammam 1 Umm Er Raduma 200 202000000 203000000 -1000000

10 Dammam 1 Simsima 600 301000000 202000000 99000000

11 Dammam 1 Mishrif 1000 304000000 301000000 3000000

12 Dammam 1 Ahmadi 2000 305000000 304000000 1000000

13 Khurais 1 Dammam 0 201000000 305000000 -104000000

14 Khurais 1 Rus 100 203000000 201000000 2000000

15 Khurais 1 Umm Er Raduma 300 202000000 203000000 -1000000

16 Khurais 1 Simsima 1000 301000000 202000000 99000000

17 Khurais 1 Mishrif 2000 304000000 301000000 3000000

18 Khurais 1 Ahmadi 4000 305000000 304000000 1000000

19 Khurais 1 Nahr Umr 3500 307000000 305000000 2000000

307000000

22Use Database to Use Database to

Query out smallerQuery out smaller

Negatives to findNegatives to find

SuperpositionSuperposition

ProblemsProblems

1 1 Shift and SubtractShift and Subtract

Sequence CodeSequence Code

in Spreadsheetin Spreadsheet

3 3 Prioritize and Prioritize and

Adjust Adjust

Sequence CodesSequence Codes

Up ToUp To

6 cycles6 cycles

Spreadsheet Spreadsheet -- Database CycleDatabase Cycle

for correcting superposition problemsfor correcting superposition problems

STARTEXP

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Graph of Graph of

Stratigraphic Stratigraphic

Database showing Database showing

Number of Well Number of Well

cuts through each cuts through each

age:age:

Arabian PlateArabian PlateSTARTEXP

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Using Surface Geology to Using Surface Geology to

constrain mappingconstrain mapping

• A grid of points has been run through each

surface geology polygon.

• By putting the grids into a database we make

composites of sub crop geology at System level to

constrain isopach mapping.

STARTEXP

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Database of Surface Geology Points created toDatabase of Surface Geology Points created to

enable constraint of isopach zero edgesenable constraint of isopach zero edges

Based on USGS geologySTARTEXP

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Query (Query (REDRED))

for wells that spud in sub cropfor wells that spud in sub crop

• Query out wells that have a minimum age

older than the earliest age of the interval to

be mapped.

• Give these wells a thickness value of -11

STARTEXP

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Query to find wells that spud below interval: Query to find wells that spud below interval:

Plotted as red symbols given value of Plotted as red symbols given value of --10 for 10 for

griddinggridding

STARTEXP

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QueryQuery (WHITE)

for wells missing tops from the for wells missing tops from the

interval to be mappedinterval to be mapped

• For wells that have records older and younger

than the interval.

• Remove records that are younger or older than

interval to be mapped.

• Count remaining records for each well.

• Assign thickness value of -5 to wells that have no

records.

• Plot these wells as white dots.

STARTEXP

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Query to find wells with subsurface pinch outs: Query to find wells with subsurface pinch outs:

Plotted as white symbols given value of Plotted as white symbols given value of --5 for 5 for

griddinggridding

STARTEXP

http://Startexp.com


Dual Query System:Dual Query System:

First Thickness CalculationFirst Thickness Calculation

• From the set of wells that have records younger

and older than the interval.

• Find the maximum and minimum depth record for

each well within the interval and subtract the

minimum depth from the maximum depth. Then

store this result as a table.

STARTEXP

http://Startexp.com


Dual Query System: Dual Query System:

Second Thickness CalculationSecond Thickness Calculation

• From the set of wells that have records above and

below the interval.

• From well top records with ages within the

interval, find the minimum depth for each well.

• From a set of well top records with ages older

than the interval find the minimum depth.

• Subtract the smaller depth from the larger depth.

STARTEXP

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Dual Query System for Sequence Thickness Dual Query System for Sequence Thickness

TIME

Query 1 Query 2

1) Match depths to time.

2) Calculate thickness

for Query 1 and Query 2.

3) Subtract for error checking

4) Filter out problem wells.

5) Take maximum thickness.

TOP

STARTEXP

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Stratigraphic Thickness Elevation Plot for Upper and Stratigraphic Thickness Elevation Plot for Upper and

Middle JurassicMiddle Jurassic

STARTEXP

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Penetration wells:Penetration wells:

GRAYGRAY & & YELLOWYELLOW

• Wells that do not penetrate entire sequence

• Find by query.

• Adjust for :

– Zero edge extension

– Depocenters

STARTEXP

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Query to find wells with penetrations that impact Query to find wells with penetrations that impact

interpretation: Plotted as value of penetration and given interpretation: Plotted as value of penetration and given

yellow symbol. Gray symbol designates wells that yellow symbol. Gray symbol designates wells that

penetrate but do not impact interpretation.penetrate but do not impact interpretation.

STARTEXP

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Sub-crop

Wells

Missing in

Subsurface

Wells

Thickness

Calculation

Wells

Penetration

Action

Wells

Surface

Outcrop

CompositeComposite

Table for Table for

GridGrid

Penetration

Wells

Two Judgments

STARTEXP

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Contrast of Maps showing thickness Contrast of Maps showing thickness

constraints only with system used in this constraints only with system used in this

Study : Upper and Middle Jurassic exampleStudy : Upper and Middle Jurassic example

STARTEXP

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Quality ControlQuality Control

• Superposition and age assignment

• Step Plots

• Dual thickness query

• Laying on map for comparison (five query products)

– surface map sub crop

– wells spudding in sub crop

– interval missing in subsurface

– wells with thickness calculation (Dual Query)

– wells with penetration and taking selective action

– mapping result

• Filters

– 1) data quality and 2) structural repeats

STARTEXP

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Begin Slide Show of MapsBegin Slide Show of Maps

We have posted some interesting

new wells and discoveries in RED

on specific maps

STARTEXP

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Slide Show of sequences of the Slide Show of sequences of the

Arabian PlateArabian Plate

The show is a series of maps each preceded

by a slide which gives my “cliff note” version of

what is important in so far as hydrocarbon geology

concerning each chronostratigraphic sequence.

The progression is down-section.

Watch control. Remember:

Black = thickness = variable

Dusky Red area = sub crop outcrop = -10

White = subsurface missing = -5

Red = well sub crop spud = -11

Gray = well penetration

Yellow = well penetration with action = variable

STARTEXP

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Importance of NeogeneImportance of Neogene

• Evaporite Seal for Zagros Dezful and Northern

Iraq

• Subsidence-Driven Maturation along the

Northwest boundary of Arabian Plate

STARTEXP

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Neogene

Isopach

http://Startexp.com

Importance of OligoceneImportance of Oligocene

• BIG OIL: Provides major reservoir (Asmari)

for Zagros and Iraq.

• Note restricted distribution sandwiched

between Neogene above and Paleocene-

Eocene below.

• Where will the first major stratigraphic

discovery be made?

STARTEXP

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OligoceneOligocene

IsopachIsopach

http://Startexp.com

Importance of PaleoceneImportance of Paleocene--EoceneEocene

• Broad regional subsidence brings vast area

to regional threshold of maturation.

• Source of gas and oil in northern Dezful

embayment of Iran.

• Behaves as vertical carrier system

– Note isopach thin in area of Kirkuk, northern Iraq

may have aided focusing of carrier system

●● TawkeTawke--11 ●● ShakalShakal--11

STARTEXP

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Eocene andEocene and

PaleocenePaleocene

IsopachIsopach●● TawkeTawke--11

●● ShakalShakal--11

http://Startexp.com

Importance of Upper CretaceousImportance of Upper Cretaceous

• Many individual Basins differentiated, for

example the Euphrates Graben.

• Major OIL: Majnoon

• Three or more distinctly aged source units.

• Difficult to correlate.

• Under-explored.

●● TawkeTawke--11 ●● Miran WestMiran West--11●● BinaBina--BawiBawi--11

STARTEXP

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Upper

Cretaceous

Isopach●● TawkeTawke--11

●● BinaBina--BawiBawi--11●● Miran WestMiran West--11

http://Startexp.com

Importance of Middle CretaceousImportance of Middle Cretaceous

• BIG OIL: Burgan, Safaniya Sandstone

Reservoirs

• Source Rock

• Important carbonate reservoirs

STARTEXP

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Middle

Cretaceous

Isopach

http://Startexp.com

Importance of Lower CretaceousImportance of Lower Cretaceous

• BIG OIL: Zubair sandstone reservoirs,

Shuaiba carbonate reservoirs, Thamama

carbonate reservoirs.

• Sleeper Sequence: overlooked carbonate

reservoirs and source rock

• Problem: producing multiple thin reservoirs

STARTEXP

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Lower

Cretaceous

Isopach

http://Startexp.com

Importance of Upper and Middle Importance of Upper and Middle

JurassicJurassic

• BIG OIL: Ghawar and other Saudi fields,

carbonate reservoirs

• source rock, reservoirs, seals

• At just the right burial depth for a large part

of Basin

●● ShaikanShaikan--1 perhaps most 1 perhaps most important recent discovery important recent discovery becausebecause

It establishes Jurassic reservoir rock in IraqIt establishes Jurassic reservoir rock in Iraq

STARTEXP

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Upper and

Middle Jurassic

Isopach●● ShaikanShaikan--11

http://Startexp.com

Importance of Lias and TriassicImportance of Lias and Triassic

• Immature exploration except for Syria and

Northern Iraq.

• Oil and gas reservoirs, carbonate

• Further potential in Turkey, Jordan, and

Israel

– potential for small companies

• Source rock, seals, and reservoirs

• Frontier

●● BinaBina--BawiBawi--1 non commercial gas test and Shaikan1 non commercial gas test and Shaikan--1 oil test?1 oil test?

STARTEXP

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Lias and

Triassic

Isopach●● BinaBina--BawiBawi--11

http://Startexp.com

●● ShaikanShaikan--11

Importance of PermianImportance of Permian

• BIG GAS: North Dome, North Pars, South

Pars, etc. carbonate reservoirs, anhydrite

seals. See http://en.wikipedia.org/wiki/File:Iran_Gas_Fields_Location.GIF)

• Basal sandstone reservoirs in Saudi Arabia

and Oman oil play, red bed seals

• Sourced from below: Silurian and late

Precambrian and Cambrian, across

unconformity

STARTEXP

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Permian

Isopach

http://Startexp.com

Importance of CarboniferousImportance of Carboniferous

• Almost restricted to Syria

• Significant gas reservoirs

• Possible gas source: coals

• Observe impact of Hercynian erosion or non-

deposition on isopach distribution of

Carboniferous, Devonian, Silurian, and

Ordovician.

STARTEXP

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Carboniferous

Isopach

http://Startexp.com

Importance of DevonianImportance of Devonian

• Major Gas reserves in deep Ghawar could

become a major gas and oil play on the

Arabian Plate

• Definitely “Frontier”

• Near shore marine sand and carbonate

reservoirs.

STARTEXP

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Devonian

Isopach

http://Startexp.com

Importance of SilurianImportance of Silurian

• Major Source rock interval

– multiple intervals, wide spread

• Source of both oil and gas

• Sandstone reservoirs at Akkaz, western

Iraq

• Seal sequence with potential underlying

Ordovician sandstone reservoirs.

●● ArpatepeArpatepe--11 ●● AkkasAkkas--11

STARTEXP

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Silurian

Isopach●● ArpatepeArpatepe--11

●● AkkasAkkas--11

http://Startexp.com

●● RishaRisha--11

Importance of OrdovicianImportance of Ordovician

• Frontier

• Gas Production at Risha in western Jordan

• Shows of oil and gas in Turkey

• Facies: sandy in south grading to more fine-

grained to north.

●● AkkasAkkas--11●● ArpatepeArpatepe--11

STARTEXP

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Ordovician

Isopach●● ArpatepeArpatepe--11

●● AkkasAkkas--11

http://Startexp.com

●● RishaRisha--11

Importance of CambrianImportance of Cambrian

• Late Precambrian

• Oman

• Source rock (very rich and thick, Salt, salt-

related trapping and salt tectonics

• See “Half Graben” on isopach

STARTEXP

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Cambrian

Isopach

http://Startexp.com

Importance of PrecambrianImportance of Precambrian

• Infracambrian

– Hormuz salt “structure maker”

– Huqf Group source rocks (silicilyte facies)

• “Basement” Reservoirs

– Yemen

• Large oil columns and reserves

• Multiple fields and prospects

– Egypt

STARTEXP

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Precambrian

Yemen Basement

discoveries

Egypt/GOSbasement

discoveries

Subsurface

Precambrian in

yellow,

Precambrian

outcrop in dark

brown, young

oceanic crust in

blue, young

volcanic in

magenta

http://Startexp.com

Basement Play in YemenBasement Play in Yemen

Schlumberger

STARTEXP

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The EndThe End

PostScript: If you would like a file of

the narrative to go with these slides send and email request to [email protected]

Date post:	18-Jan-2015
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Arabian Plate Chronostratigrahic Maps

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