Marine Depositional COPYRIGHT Depositional Environments...

Marine Depositional Environments Basics Marine Carbonates

Depositional Environments

(Last Updated 28 December 2015)

COPYRIGHT

NOTICE AND DISCLAIMER

The information contained herein and/or these workshop/seminar proceedings (WORK) was prepared by or contributed to by various parties in support of professional continuing education.

For purposes of this Disclaimer, “Company Group” is defined as PetroSkills, LLC.; OGCI Training, Inc.; John M. Campbell and Company; its and their parent, subsidiaries and affiliated companies; and, its and their co-lessees, partners, joint ventures, co-owners, shareholders, agents, officers, directors, employees, representatives, instructors, and contractors.

Company Group takes no position as to whether any method, apparatus or product mentioned herein is or will be covered by a patent or other intellectual property. Furthermore, the information contained herein does not grant the right, by implication or otherwise, to manufacture, sell, offer for sale or use any method, apparatus or product covered by a patent or other intellectual property right; nor does it insure anyone against liability for infringement of same.

Except as stated herein, COMPANY GROUP MAKES NO WARRANTIES, EXPRESS, IMPLIED, OR STATUTORY, WITH RESPECT TO THE WORK, INCLUDING, WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

Company Group does not guarantee results. All interpretations using the WORK, and all recommendations based upon such interpretations, are opinion based on inferences from measurements and empirical relationships, and on assumptions, which inferences and assumptions are not infallible, and with respect to which competent specialists may differ. In addition, such interpretations, recommendations and descriptions may involve the opinion and judgment of the USER. USER has full responsibility for all interpretations, recommendations and descriptions utilizing the WORK. Company Group cannot and does not warrant the accuracy, correctness or completeness of any interpretation, recommendation or description. Under no circumstances should any interpretation, recommendation or description be relied upon as the basis for any drilling, completion, well treatment, production or other financial decision, or any procedure involving any risk to the safety of any drilling venture, drilling rig or its crew or any other individual. USER has full responsibility for all such decisions concerning other procedures relating to the drilling or production operations. Except as expressly otherwise stated herein, USER agrees that COMPANY GROUP SHALL HAVE NO LIABILITY TO USER OR TO ANY THIRD PARTY FOR ANY ORDINARY, SPECIAL, OR CONSEQUENTIAL DAMAGES OR LOSSES WHICH MIGHT ARISE DIRECTLY OR INDIRECTLY BY REASON OF USER’S USE OF WORK. USER shall protect, indemnify, hold harmless and defend Company Group of and from any loss, cost, damage, or expense, including attorneys’ fees, arising from any claim asserted against Company Group that is in any way associated with the matters set forth in this Disclaimer.

The Content may not be reproduced, distributed, sold, licensed, used to create derivative works, performed, displayed, transmitted, broadcast or otherwise exploited without the prior written content of the Company Group. Use of the WORK as a reference or manual for adult training programs is specifically reserved for PetroSkills, LLC. All rights to the WORK, including translation rights, are reserved.

© COPYRIGHT PETROSKILLS, LLC., 2015

THIS WORK IS COPYRIGHTED BY PETROSKILLS, LLC. AND DISTRIBUTED UNDER

EXCLUSIVE LICENSE BY PETROSKILLS, LLC.

COPYRIGHT

DELIVERING KNOWLEDGE. DEVELOPING COMPETENCE.

Marine DepositionalEnvironments Basics

Marine Carbonates Depositional Environments

© 2015 PetroSkills, LLC. All rights reserved.

Depositional Environments

Processes and examples from modern and ancient environments with oil field examples– Subaerial

Alluvial fanFluvial – braided and meanderingAeolian – wind and desert

– Marginal marineDelta – river, wave, tide dominated, fan delta, braid deltaBeach and barrier island

– MarineSubmarine fan – channel-levee complex, Bouma

sequenceCarbonates – limestone, dolomite

Reef, platform, pinnacle, pelagicDiagenesis

2

Marine Depositional Environments Basics _________________________________________________________________________________________________________


©2015 PetroSkills, all rights reserved PetroSkills, LLC._________________________________________________________________________________________________________

1

COPYRIGHT


Objectives of the Carbonates Session

You will learn about:– Environments of carbonate deposition

Reef

Shelf

Pinnacle

Ramp

Pelagic

– Factors that regulate carbonate depositionWater temperature

Turbulence

Organisms

3

© 2015 PetroSkills, LLC. All rights reserved. 4

Rock Type Abundance and Production by Rock Type




2

COPYRIGHT


Environments of Deposition for Carbonates


Carbonate Classification Scheme




3

COPYRIGHT




Selected Environments of Deposition for Marine Carbonates




4

COPYRIGHT



Textures Expected Basinward of the Platform Rim




5

COPYRIGHT


Carbonate Mudstone


Pelagic Limestone from the North Sea

12

Fine-textured limestone consisting of calcareous tests (shells) of floating organisms deposited mostly in basins, but sometimes on shelves.

Can have high porosity but typically low permeability.




6

COPYRIGHT


Late Cretaceous Chalk Outcrop: Etretat, France

Note: Cliff is approx. 120 m cliffin height.

Same age as the “White Cliffs of Dover” on the other side of the English Channel.


Ekofisk Field, Central Graben, North Sea

An example of production from pelagic limestones.

5.5+ TCF Gas3.4 BBO+ NGLs

Discovered in 1969 by Phillips PetroleumCompany

244 m (801 ft) of vertical closure and a hydrocarbon column 305 m (1,001 ft) long, formed by Permian Zechstein salt movement in the form of salt pillows




7

COPYRIGHT


Cretaceous and Paleocene Aged Chalks


1960s–1970s Vintage Seismic Line Over Ekofisk Field

Ekofisk structureappears to havecollapsed with alow developedover what wouldhave been the structural crestof the field.




8

COPYRIGHT


Original Structure Map Over Ekofisk Based on Seismic


Log Cross Sections Over Ekofisk Field

Note: Well control indicates there is no structural low but simply a large anticlinal structure.




9

COPYRIGHT


Post Drilling and Seismic Reinterpretation of Ekofisk


Gas “Cloud” Over Crest of Structure Causes Low Velocity




10

COPYRIGHT


Carbonate Deposits Near the Rim (Reef)


Carbonate Deposits Near the High Energy Rim (Reef)




11

COPYRIGHT


Belize Barrier Reef: A Rimmed Shelf

Water depth to left is 100+m (300′ +).

Behind reef, depth 4–5m (18′).

Over reef, where you see waves, the water is less than 2′ (0.6m).

Reef is 200km long and the shelf is 40km wide.


Belize Barrier Reef: Robust Corals Growing

24




12

COPYRIGHT


Belize Barrier Reef: Mostly Dead Reef Material

25

Notice 4.5 foot long Morey Eel

Very large porespaces in Boundstones if pore space could be preserved


El Capitan Reef Complex, Guadalupe Peak, West Texas

26

Basin to Reef Crestpreserved with2000 feet ofexposed rock

The perfect place to studycarbonates…the West TexasDesert.

So why doeseveryone wantto go on fieldtrips toBelize and theBahamas?




13

COPYRIGHT


El Capitan and Delaware Basin Stratigraphy


Textures Behind a Rim or on a Platform




14

COPYRIGHT


Carbonate Facies Belts with Representative Textural Types





15

COPYRIGHT


Oolites: Form in Areas of Higher Energy Agitated Waters

31


Oolites: In Thin Section, Notice Seed Crystal in Centers

32




16

COPYRIGHT


Oolite Shoal in the Bahamas:Potentially 225 sq. km of Potential Reservoir


Distribution of Cretaceous Carbonate Platforms on Cretaceous (100Mya) Plate Positions




17

COPYRIGHT


Quiet Water Lagoonal Facies


Dry Tortugas, 120 Miles From Land East of Florida

36

Laterally extensive, shallow carbonate shelf, 120 miles from land…no clastics.

Mostly carbonate mudstones.




18

COPYRIGHT


Patch Reefs near Blue Hole, Lighthouse Reef, Belize

37


Small Patch Reef Within Platform Carbonates: Saudi Arabia

38




19

COPYRIGHT


Textures Behind a Rim or on a Platform





20

COPYRIGHT


Green Algae that Creates Sandsize to Claysize Carbonate



42

CaCO3 secreting algae: yield >85% sand and clay size particles

Halimeda: bottom right example – Sand size plates

Pennicillus: fan shaped – Clay size plates




21

COPYRIGHT




Sand Sized Carbonate Pellets Due to the Action of Worms

44

Thin section of a Carbonate Pellet Grainstone –sand size

Worms and their effects




22

COPYRIGHT


Monotonous Lagoonal Carbonates West of San Antonio, Texas


What is the effect on shelf deposits when there are multiple cycles of rising and falling sea level?

46




23

COPYRIGHT


Humid, Carbonate, Rimmed Shelf

Porosity development in low stand due to dissolution of exposed carbonate system.

Organics deposited in high stand during flooding.


Blue Hole, Lighthouse Reef, Belize

The Blue Hole…A mystical place from those in Belize.

Water depth at rim is 10′—hole is 340′ deep, diameter is 1000′ (300m).

Possibly related to Pleistocene lowstand.




24

COPYRIGHT


Blue Hole, Lighthouse Reef, Belize

At a depth of 130–170 feet, there are

stalactites and stalagmites.

These only form in the presence of air with dripping water, typically in caves.

Sea level during last glaciation about 340 feet deeper than today.


Devonian carbonates and two wells in the Canning Basin, Australia, show the stacking of sedimentary units and repetition of systems tracts generated by cyclical rises and falls on sea level

50




25

COPYRIGHT


Devonian Platform Distribution, Canning Basin, Australia


Devonian Platform Distribution, Canning Basin, Australia




26

COPYRIGHT


Stacked Sequences in two Wells in the Canning Basin, Australia


Sequence Model of the Frasnian-Famennian (Devonian) Reef Complex, Canning Basin, Australia




27

COPYRIGHT


Productive Examples of Carbonate Platforms

Ghawar Field on Arabian Platform

Largest producing Oil and Gas field in the world

Production from several levels

174 miles by 19 miles in aerial expent

OOIP of 200 billion barrels?


Diagrammatic of Permian Carbonate Depositional Environments

Great lateral extent of Permian environments on Arabian platform “restricted, evaporitic facies”

Less than 15′ water, mostly algae producing fine grained carbonates

Compressional fault bounded structure related to Arabian-Asian plate collision




28

COPYRIGHT


Map of Khuff-C (Permian) Gas on the Ghawar Structure

Cross section of sonic logs on next slide


Khuff-C Porosity Distribution

Sonic Logs over Ghawar showingPorosity change in the Khuff-C Reservoir




29

COPYRIGHT


Thin sections of porous and nonporous Khuff-C Reservoir

PelletoidalGrainstone… i.e. Worm excrement


Carbonate Buildups Can Also Make Detached Shelves

Starts in shallow water and keeps up...creates “platform”

Ultimate drowning

This example is from Australia.




30

COPYRIGHT


The sediments and stratigraphic characteristics of detached carbonate platforms approximate those attached platforms

61


62

62

Depositional Sequence Model Detached, Humid Rimmed Platform




31

COPYRIGHT


Petroleum production from detached carbonate platforms

63


Depositional Sequence Model Detached, Humid Rimmed Platform




32

COPYRIGHT


Seismic Line Across Tengiz Structure

65


3D Seismic Across Tengiz Structure




33

COPYRIGHT


Geological Model of Tengiz Field Post Drilling and 3D


Pinnacle Reef

Another kind of reef

68




34

COPYRIGHT


Selected Environments of Deposition for Marine Carbonates


Reef Types




35

COPYRIGHT



Production from pinnacle reefs

72




36

COPYRIGHT


Kasmin Utara and Kasmin Reefs, Indonesia


Intisar Fields, Sirte Basin Libya

Oxy drilled Intisar field in Libya2mi across (small)950′ oils column




37

COPYRIGHT


Intisar D: Field, Sirte Basin Libya


Intisar D: Field, Sirte Basin Libya

Just off Intisar reef structure—hard to see except for some minor shallow structure

Flat under reef




38

COPYRIGHT


Intisar “D: Field, Sirte Basin Libya

Over the “core” of the Intisar reef structure see drape, low compaction reef

Also see “pull down” below reef due to porosity in carbonates and/or weight of reef


North Field, Offshore Qatar and Iran

Carbonate Ramps—North Field off Qatar…filled to spill and largest gas field in the world

Conoco originally offered entire lease, 3 interpreters because so big and “NO” structure; gave up lease

Exxon and Shell picked it up and put the 3 pieces together properly

Reserves on the order of 1.3 Quadrillion cubic feet




39

COPYRIGHT




Ras Tanura Beach, Saudi Arabia, North of Worlds Largest Refinery

Oolitic sand and siliciclastic beach.

Sands brought in by long shore transport from a delta 300 miles to the north.

Note: Right where wave breaks, water goes cloudy, and then after break, water goes clear…release of CO2 due to waves and precipitation of carbonates, then back into solution.




40

COPYRIGHT


Near road to Ras Tanura, Saudi ArabiaTidal channel with CaCO3 precipitating in water (notice cloudy appearance)

Water temp 95 degrees F (38–39 C?)

Note Beachrock – early diagenesis (lithification) and maybe Dolomitization


Windward Side of Bush Key, Dry Tortugas

Boundstoneparent material




41

COPYRIGHT


Bioclastic Limestone of Crinoid Stems and Fragments

Completely cemented

0 por/perm

Super hard—hit with hammerand be sorry—

Good for making tombstone


Sarasota, Florida

Coquina in the making

Note preferred orientation of shells.

Impact on Kh>Kv ?




42

COPYRIGHT




Supratidal Deposition (Sabhka)




43

COPYRIGHT


Algal Mat, Potential Source: Abu Dhabi, UAECyanobacteria and fungi, found just above high tide line, covered with dust

Blooms when wet—turns green

One of the best source rocks there is and been there for last 120 mm years—interbedded with reservoir produces only sweet crude

2–3 mm thick


Up Close Algal Mat, Potential Source: Abu Dhabi, UAE




44

COPYRIGHT


Algal Mat, Potential Source: Abu Dhabi, UAE


Objectives of the Carbonates Session

You have learned about:– Environments of carbonate deposition

Reef

Shelf

Pinnacle

Ramp

Pelagic

– Factors that regulate carbonate depositionWater temperature

Turbulence

Organisms

90




45

COPYRIGHT


Exercise

Interpreting Carbonate Environments from Seismic




46

COPYRIGHT

Date post:	07-Jul-2020
Category:	Documents
Upload:	others
View:	9 times
Download:	1 times

Marine Depositional COPYRIGHT Depositional Environments...

Documents