Geologic Framework for the Tengiz and Korolev Fields, Kazakhstan – Carboniferous Isolated Carbonate Platforms* by Paul M

Geologic Framework for the Tengiz and Korolev Fields, Kazakhstan – Carboniferous Isolated Carbonate Platforms* By Paul M. (Mitch) Harris1

Search and Discovery Article #20060 (2008) Posted June 26, 2008

*Adapted from 2000-2001 AAPG International Distinguished Lecture

1Chevron Petroleum Technology Company, Houston, TX; currently ETC, Chevron, San Ramon, CA, USA. ([email protected])

Abstract

The supergiant Tengiz field exhibits depositional features typically observed in isolated carbonate platforms but rare for the Carboniferous: extensive inner and outer platform deposits, a raised rim feature, steep platform margins, and thick flank deposits. Many of the same platform and slope features observed in Tengiz are inferred from much less well data for Korolev.

Platform Growth and Stratigraphic Framework

The Tengiz and Korolev platforms formed during the Carboniferous on the Primorskian Arch, one of several structural highs in the southeast portion of the PriCaspian Basin in western Kazakhstan. The platform edges are abrupt, showing a relatively rapid change from the platform top (platform, shoal, or platform margin) to slope environment. Platform deposition includes cycles shoaling upward from open marine packstones to shoal grainstones. A reef (microbial boundstone with scattered megafossils) is localized to a very narrow belt along the platform margin. Boundstones give way downslope to breccias and finally argillaceous lime mudstone beds. A variety of open porosity types are present; karst zones are best developed in the rim, and fractures characterize both the rim and flanks.

A hierarchy of cycles, sequences, and composite sequences is developed by integrating core and well logs with newly acquired 3D seismic data. The stratigraphic framework, although not finalized, explains many aspects of the reservoir quality. The buildup (actual thickening) of the platforms was seemingly initiated in the Devonian and accentuated greatly during Visean time. The position of the platform margins is controlled, in part, by deep-seated faults. The areal extent of both platforms generally diminished during the Carboniferous as evidenced by backstepping of the younger margins.

Key Platform Well

Tengiz well T-220, because of the great amount of continuous core taken in the well, is invaluable from the perspective of understanding the nature of deposition, stratigraphy, diagenesis, reservoir quality, and log response for the interior portion of the platform. The upper contact of the Bashkirian is significant as it represents the demise of the shallow water platform. Three sequences of similar grainstone-dominated deposits form a composite sequence that comprises most of the Bashkirian. Four sequences recognized within the Serpukhovian form another composite sequence. The boundary between the Bashkirian and Serpukhovian is significant as it represents a major change in the style of deposition on the top of the Tengiz platform and equates with a time gap. Serpukhovian facies reflect slightly deeper water and more skeletal-rich environments. Three composite sequences are tentatively identified within the Visean (Oksky) interval; each contains three sequences consisting of grainstone-packstone cycles that are similar to those of the Serpukhovian. A portion of one sequence recognized within the upper part of the Visean (Tula) contains packstone-grainstone cycles. The difference in the character of the cycles between the Visean (Oksky)-Serpukhovian and the Bashkirian reflects changes in the nature of sea-level variations that occurred between Early and Late Carboniferous.

Porosity loss in T-220, and other Tengiz platform wells, is by calcite cementation and minor compaction. The variety of open primary and secondary pore types is a principal reason for the permeability variation that is observed within the well. Core samples are dominantly limestone with local partial dolomitization and silicification associated with tuffs or subaerial exposure.

T-220 displays more-or-less constant 15% porosity with 1-10 md permeability, separated by thin tighter intervals at sequence and cycle boundaries. Where bitumen occurs, it displays an inverse correlation with porosity (that is, bitumen is more abundant in rocks with low porosity). Samples with bitumen occur in short intervals, almost always at sequence or cycle boundaries, with long intervals in between with zero bitumen. The downhole porosity logs show an excellent match to core porosities; gamma-ray response increases where tuffs and shales are present.

Key Flank Well

Tengiz well T-47 is a flank well located off the southeast edge of the platform; it is an important well from the perspective of understanding the nature of deposition, diagenesis, reservoir quality, and log response in the flanks of the platform.

The Bashkirian through Visean (Oksky) consists of two general rock types: (1) coarse-grained (rudstones and grainstones rich in boundstone intraclasts), and (2) finer-grained (grainstones, packstones, and wackestones). Both rock types represent debris that was shed down the slope from the platform margin. The Visean (Tula) is predominantly fine-grained slope packstones. The Devonian (Famennian) consists of shallow platform grainstones and packstones.

T-47 penetrated a generally limestone stratigraphy, with three important exceptions: (1) dolomite-rich intervals with 50% to 70% dolomite in the basal Serpukhovian, and lower Visean (Tula) through top Devonian; (2) a silica-rich interval in the Visean (Tula); and (3) a barite-rich interval with 0% to 26 wt.% (17 vol.%) barite near the top Devonian. Bitumen fills 10% to 15% of the potential porosity (defined as core measured porosity plus bitumen) in most samples.

The Bashkirian through Visean (Oksky) slope deposits have open porosity of three types: isolated vugs, pores between clasts, and microfractures. The Visean (Tula) packstones are varyingly silicified, and a few small, open vugs are the only visible porosity. Wireline logs indicate a porosity distribution that is generally consistent with the limited core data. Small, isolated, bitumen-stained vugs, fenestral pores, and microfractures remain open in a few Devonian grainstone and packstone samples.

Wireline logs indicate a porosity distribution that is generally consistent with the limited core data. Porosity from 0% and 9% typifies the section above the Devonian; porosity generally <4% is representative for the Devonian. The Visean (Oksky) slope deposits appear on an FMI log as irregular layers dipping up to 30° that are rarely continuous across the image, and thin continuous layers gently dipping way from the platform characterize the Visean (Tula) slope deposits. Irregular continuous layers with dips <5° typify the Devonian platform deposits.

Acknowledgements

I am grateful to the following coworkers for their collaboration: Michael E. Clark, Tengizchevroil, Tengiz, Kazakhstan; Raymond A. Garber, Chevron Petroleum Technology Company, Houston, TX; and Jeff. L. Warner, LA Petrophysical, La Habra Heights, CA.

GEOLOGICGEOLOGIC FRAMEWORKFRAMEWORK FORFOR TENGIZTENGIZ ANDAND KOROLEVKOROLEV FIELDS,FIELDS, KAZAKHSTANKAZAKHSTAN

CARBONIFEROUSCARBONIFEROUS ISOLATEDISOLATED CARBONATECARBONATE PLATFORMSPLATFORMS

AAPG International Distinguished Lecture Tour

Paul M. (Mitch) Harris Chevron Petroleum Technology Company Houston, Texas U.S.A. OUTLINEOUTLINE OFOF TALKTALK

GeologicalGeological SettingSetting

KeyKey PlatformPlatform WellWell

KeyKey FlankFlank WellWell

SummarySummary LOCATIONLOCATION MAPMAP

Atyrau TENGIZCHEVROIL JOINT VENTURE

JV BLOCK 4000 km 2

Cas pi an Korolev Sea Field Tengiz Field

30 Mi 30 Km KAZAKH S T A N TIMINGTIMING OFOF IMPORTANTIMPORTANT EVENTSEVENTS Kun Kaz a nia n Capitan Guadalupian Word Ufimian Irensky Art 260 Ku n g u ri a n Philipovsky SALT DEPOSITION Le o nardia n Saraninsky Sarginsky Harland et al. Artins kian Irch insky Burtse vsky 270 Sac Sterlitamaksky Sakmarian Tastubsky Wo l f c a mp i a n 280 Shihahsky As s As s e lian Holodnolozsky Wabaunsee Noginsky Noginsky NON-DEPOSITION Pavlovo-Posadsky Shawnee Douglas Klaz'minskiy Dobryatinsky 290 Dorogomilovsky Dorogomilovsky Lansing Khamovnichesky Khamovnichesky Kansas City Missourian Vir Pleasanton Krevyaninsky Krevyaninsky Marmaton Myachkovsky Myachkovsky C Cherokee Podol'skiy Podol'skiy C 300 Kashirsky Kashirsky Mss Vereiskiy Vereiskiy Winslow Melekessky Melekessky drowning Des Bloyd Cheremchanskiy Cheremchanskiy C 310 Prikamsky Prikamsky Ato/Der Severokel'tenskiy Severokel'tenskiy C Hale Mor Krasnopolyansky Krasnopolyansky 320 unconformity Vosnesensky Voznesensky Chs Zapaltyubinsky Zapaltyubinsky Elvirian Protvinsky Protvinsky 330 Steshevsky Steshevsky Hombergian Tarussky Tarussky Venevsky Venevsky Mer Gasperian St. Genevieve Mikhailovskiy Mikhailovskiy C PLATFORM BUILD-UP 340 St. Louis Aleksinsky Aleksinsky Salem Tul'skiy Tul'skiy Warsaw Ilychskiy Bobrikovsky Osa 350 Keokuk Pester'kovskiy Radayevsky Burlington Fern G len Kos'vinskiy Kos'vinskiy Meppen Kizelovsky Kizelovsky Chouteau Cherepetsky Cherepetsky Kin Hannibal Upinsky Upinsky Glen Park Malevsky Malevsky 360 Kalinovsky Gumerovsky Zavolzhsky Upper Dankovsky Fam Lebedyansky Lower Zandonsky-Eletsky D Livensky Evlans Upper Voronezhsky 370 Mendymskyky Frs Middle Buregsky SargayevskySemiluks Kynovskyky Lower Pashiysky Mullinsky Give tian Ardatovsky Giv 380 Vorob'yevsky Biysky Eif Eife lian Koivensky Afoninsky PLATFORMPLATFORM EVOLUTIONEVOLUTION Ma (BASE) HORIZONS RUSSIAN STAGES RUSSIAN SERIES 311.5 (top)- Asatausky (Asa) LATE DROWNING 312.0 Tashastinsky (Tas) 312.5 BASHKIRIAN EARLY MIDDLE 312.8 Askynbashsky (Ask) CARBONIFEROUS 313.2 Akavassky (Ak) EARLY 313.6 Syuransky (Syu) 314.0 Bogdanovsky (Bog) UNCONFORMITY 316.75 Zapaltyubinsky (Zap) LATE 319.5 Protvinsky (Pr) SERPUKHOVIAN 322.25 Steshevsky (St) EARLY 325.0 Tarussky (Tar) 328.5 Venevsky Oksky (Ven) Super- LATE 330.5 Mikhailovsky horiz. VISEAN LOWER (Mik) CARBONIFEROUS 332.75 Aleksinsky (Al) 335.0 Tulsky (Tul) 341.5 Bobrikovsky (Bob) EARLY UNCONFORMITY 343.0 Radaevsky (Rad) 345.5 Kosvinsky (Kos) LATE 348.0 Kizelovsky (Kiz) 349.5 Cherepetsky (Ch) TOURNAISIAN 351.0 Upinsky (Up) EARLY 352.5 Malevsky (Mal) 354.0 Gumerovsky (Gum) UNCONFORMITY 364.5 FAMENNIAN LATE 369.0 FRASNIAN DEVONIAN TENGIZTENGIZ

WELLWELL PLATFORM LOCATIONSLOCATIONS

FLANK TENGIZTENGIZ 33--DD SEISMICSEISMIC TENGIZTENGIZ 33--DD SEISMICSEISMIC KOROLEVKOROLEV FIELDFIELD MAPMAP PLATFORM FLANK KOROLEVKOROLEV 33--DD SEISMICSEISMIC KOROLEVKOROLEV 33--DD SEISMICSEISMIC TENGIZTENGIZ 33--DD SEISMICSEISMIC

BASHKIRIAN

EARLY VISEAN

DEVONIAN

PLATFORM FLANK FLANK TENGIZTENGIZ STRATIGRAPHICSTRATIGRAPHIC MODELMODEL PLATFORM STYLE BASHKIRIAN DROWNING RETROGRADING

MAJOR SB SERPHUKHOVIAN FLANK DEPOSITION PROGRADING AGGRADING

LATE VISEAN AGGRADING FILL-IN RELIEF

EARLY VISEAN RELIEF ON MAJOR SB AGGRADING BACKSTEP

TOURNAISIAN AGGRADING

DEVONIAN MAJOR SB AGGRADING TENGIZTENGIZ STRATIGRAPHICSTRATIGRAPHIC MODELMODEL

SW NE T-5056 T-220 T-5050

4000 3900 4000 DROWNING

4100 RETROGRADING 4000 BASHKIRIAN 4100 MAJOR SB 4200 SERPUKHOVIAN 4100 SERPUKHOVIAN AGGRADING 4200

4300 FLANK DEPOSITION4200 4300

LATE VISEAN 4400 T-463 AGGRADING 4300 T-41 T-463 4400 T-41

PROGRADING 4300 4500 4500 FILL-IN RELIEF 4400 4500

4400

4600 RELIEF ON SB 4500 4600

4500 4700 AGGRADING 4600 EARLY VISEAN 4700 BACKSTEP 4600

4800 4700 AGGRADING 4800

4700

4900 4800

4900 AGGRADING 4800 5000 TOURNAISIAN AGGRADING 4900 5000

4900

5100 5000

5100

5200 MAJOR SB 5100 5200

5300 DEVONIAN AGGRADING 5200 5300

5400 5300

5400

5500 5400

5500

5600

(~ 5X vertical exaggeration) 5700 TENGIZTENGIZ GEOLOGICGEOLOGIC MODELMODEL August 2000 - Structural Datum

T-463 T-220 T-5050 T-5056

SB ~312 MA T/BASH • MINOR FLANK • GENERALLY RETROGRADATIONAL T/BASH SB ~314 MA T/SERP T/SERP • SERP DOMINATES FLANK T/L.VIS • AGGRADING THEN PROGRADING MARGIN • MAJOR BACKSTEP

Improved Reservoir SB ~337 MA Quality T/E. VISEAN T/E. VISEAN • RELIEF ON SEQUENCE BOUNDARY • AGGRADING PLATFORM • MINOR MARGIN/SLOPE T/TOURN SB ~354 MA T/DEVONIAN T/DEV • FAMENNIAN PLATFORM SMALLER • PLATFORM MARGIN/SLOPE POSSIBLE T-10 z T-17 z 5,8005,800 0 5,60 T-41 z ,400 5 0 5,20 ,000 T-40 T-9 5 00 z T-103 z 4,8 0 4,60 z T-8 ,400 4 T-102 z T-1K z T-108 T-42 z T-7 z z z z T-107 T-6 z T-1100 T-1101 z T-39 z T-16 T-43 z T-419 T-1 T-3K T-4 T-38 z z z z z z z z T-106 T-5050 T-70 T-5 z T-72 z T-320 z z z T-105 z T-113 KEYKEY z T-112 T-118 T-11 z T-15 z T-20 z T-111 T-24z z z T-117 z T-104 z T-318z z T-110 z T-5K T-19 T-317 z z PLATFORMPLATFORM z z T-14 z T-116 T-122 T-37 T-109 T-115 z T-220 z T-27 T-26 z T-44 T-220 T-121 z z z z T-21 z z T-22 zT-100 T-114 z T-120 z z z T-25 WELL T-119 WELL z z T-28 T-124 z T-23 z T-29 T-12 z T-123 z z z T-47 North z T-30 z T-31 z T-34 z

4,200 T-45 Tengiz Reservoir z 4,400 4,600 Top Bashkirian (m) 4,800 5,000 012 5,200 5,400 Kilometers 5,600 FLANK PLATFORM Highstand Facies

Shoal (Grainstone) Shallow Platform (Cyclic Packstone and Grainstone Platform Margin with Crinoids, Algae and Locally Reefs (Reef and Grainstone) ) Slope (Breccias) Fully Developed Carbonate Platform Top, Margin and Flanks Toe-of-Slope (Mud and Grainstone DEPOSITIONALDEPOSITIONAL Debris) Transgressive Facies MODELMODEL

Packstone with Crinoids, Brachiopods, and Locally Reef Mounds Deposition on Slope Deep Platform

Lowstand Facies

Karst Calcrete Non-Deposition

Subaerial Exposure

Minor Deposition on Slope BASHKIRIANBASHKIRIAN MODELMODEL

PLATFORM MARGIN TOE OF PLATFORM SHOAL COMPLEX OUTER PLATFORM SLOPE UPPER LOWER AND SLOPE SLOPE BASIN 50 m 50 m - OOID, PELOID, - 30 SKELETAL GRAINSTONE 30 mB mB SKELETAL PELOID mB mB GRAINSTONE/PACKSTONE M SKELETAL PELOID IC R PACKSTONE/GRAINSTONE O B B + MICROBIAL BOUNDSTONE O IA U L N S T O N E AND SLOPE DEBRIS GOOD INTERPARTICLE POROSITY IN PLATFORM PLATFORM AND SLOPE DEBRIS PLATFORM CYCLES THIN, POTENTIALLY DISCONTINUOUS AND MUDSTONE

MINOR EQUANT CALCITE FILLING INTERPARTICLE POROSITY SERPUKHOVIANSERPUKHOVIAN -- LATELATE VISEANVISEAN MODELMODEL

TOE OF PLATFORM PLATFORM SHOAL COMPLEX OUTER PLATFORM SLOPE MARGIN AND SLOPE AND BASIN 20 m 20 m SKELETAL PELOID GRAINSTONE/PACKSTONE mB ACCRETIONARY mB BOUNDSTONE (CPM) 300 m 300 m SKELETAL PELOID PACKSTONE/GRAINSTONE BOUNDSTONE + MICROBIAL BOUNDSTONE BRECCIA

CPM=CLOTTED PELOIDAL DETRITAL MICRITE BRECCIA

BEST POROSITY AND MATRIX PERMEABILITY IN PLATFORM FACIES BEST PERMEABILITY IN PLATFORM MARGIN AND SLOPE BOUNDSTONES - LIME MUDSTONE AND PLATFORM CARB. SURFACE - BURIAL KARST AND/OR TECTONIC FRACTURES DEBRIS

BITUMEN FILLED POROSITY INCR. TOWARD PLATFORM MARGIN AND SLOPE Lithology Distribution -- Bashkirian Sequences

B1 Clastic P/W'stone B2 Packstone B3 G/P'stone B4 Grainstone

0% 20% 40% 60% 80% 100%

Lithology Distribution -- Serpukhovian Sequences

S1 Clastic STRATIGRAPHYSTRATIGRAPHY P/W'stone S2 Packstone S3 G/P'stone ANDAND Grainstone S4 ROCKROCK TYPETYPE 0% 20% 40% 60% 80% 100%

Lithology Distribution -- Visean (Oksky) Sequences Sequences VO1 Clastic VO3 P/W'stone Packstone VO5 G/P'stone Grainstone VO7

VO9

0% 20% 40% 60% 80% 100% PLATFORMPLATFORM CYCLECYCLE top

Grainstone Packstone 15.8% 4.5% 3.9 mD 0.06 mD

base BASHKIRIANBASHKIRIAN CYCLECYCLE

TOP SKELETAL - COATED GRAIN GRAINSTONE

4 MM ACROSS FIELD

BOTTOM SERPUKHOVIANSERPUKHOVIAN CYCLECYCLE TOP SKELETAL GRAINSTONE AND PACKSTONE

4 MM ACROSS FIELD

BOTTOM UPPERUPPER VISEANVISEAN CYCLECYCLE TOP SKELETAL - PELOID GRAIN-PACKSTONE

4 MM ACROSS FIELD

BOTTOM SUMMARYSUMMARY OFOF PLATFORMPLATFORM DIAGENESISDIAGENESIS

EARLY DIAGENESIS

RIM AND SYNTAXIAL CEMENTS MOLDIC POROSITY AND MICROPOROSITY EQUANT CALCITE CEMENTS KARST - VUGS, BRECCIA, AND MICROFRACTURES

BURIAL DIAGENESIS

MICROFRACTURES AND MICROSTYLOLITES MICROVUGGY POROSITY AND MICROPOROSITY CALCITE, DOLOMITE, SILICA, OR ANHYDRITE CEMENTS BITUMEN EMPLACEMENT AUTHIGENIC PYRITE CROSS-CUTTING FRACTURES COARSE CALCITE IN VUGS, VEINS, AND FRACTURES MOSCOVIAN (?) SEQUENCE Microporosity in grains and matrix, minor interparticle porosity, and an open microfracture. UPPER BASHKIRIAN SEQUENCE B1 - Solution-enlarged interparticle and intraskeletal porosity, microfractures, microporosity in grains and between cement crystals. LOWER BASHKIRIAN COMPOSITE SEQUENCE B2 - Solution-enhanced interparticle and intraskeletal porosity, moldic porosity, microporosity in grains, local microvuggy and microfracture porosity. B3 - Cement-reduced interparticle, moldic, microfracture, and microvuggy porosity; microporosity in grains B4 - Solution-enlarged interparticle, intraskeletal, vuggy, moldic, and microfracture porosity; microporosity in grains. SERPUKHOVIAN COMPOSITE SEQUENCE S1 - Solution-enhanced interparticle, microvuggy, moldic, and microporosity in grains. S2 - Solution-enhanced interparticle, intraskeletal, moldic, microvuggy and microfracture porosity; microporosity in grains and matrix. STRATIGRAPHYSTRATIGRAPHY S3 - Interparticle, intraskeletal, moldic, microfracture, and microvuggy porosity; microporosity in grains and matrix. S4 - Solution enhanced interparticle, intraskeletal, moldic microfracture, and microvuggy ANDAND porosity; microporosity in matrix and grains. UPPER VISEAN (OKSKY) COMPOSITE SEQUENCE VO1 - Locally solution-enhanced interparticle and intraskeletal porosity; moldic, POROSITYPOROSITY microfracture, and microvuggy porosity. Microporosity in grains and matrix. VO2 - Interparticle and intraskeletal porosity, locally solution enhanced; moldic and microvuggy porosity; microporosity in matrix and peloids. TYPE VO3 - Interparticle, moldic, and intraskeletal porosity; microporosity in grains and TYPE matrix; microvuggy and microfracture porosity. MIDDLE VISEAN (OKSKY) COMPOSITE SEQUENCE VO4 - Solution-enhanced interparticle, intraskeletal, microvuggy, and microfracture porosity; microporosity in grains. VO5 - Solution-enhanced interparticle, intraskeletal, local microvuggy porosity; microporosity in grains and matrix. VO6 - Interparticle, intraskeletal, and moldic porosity; microporosity in grains and matrix. LOWER VISEAN (OKSKY) COMPOSITE SEQUENCE VO7 - Solution-enhanced interparticle to microvuggy porosity. VO8 - Interparticle, intraskeletal, moldic and microfracture porosity; microporosity in grains. VO9 - Intraskeletal, moldic, and interparticle porosity. UPPER VISEAN (TULA) COMPOSITE SEQUENCE VT1 – Intraskeletal, moldic, and microfracture porosity; also microporosity in grains. PLATFORMPLATFORM RESERVOIRRESERVOIR QUALITYQUALITY

1000

100

10 )

1 Permeability (md 0.1 Non-Fractureed Fractured T-220 All D ata 0.01 N=1,305

0.001 0.0 5.0 10.0 15.0 20.0 25.0 Porosity (% BV) STRATIGRAPHYSTRATIGRAPHY ANDAND RESERVOIRRESERVOIR QUALITYQUALITY

1000 1000 Non-Fractured 1000 Fractured 100 100 100

10 10 10

1 1 1

0.1 0.1 0.1 Perm eability (m d) Permeability (md) T-220 T-220 Permeability (md) T-220 Lower Bashkirian Serpukhovian 0.01 0.01 0.01 Upper Visean (Oksky) N = 256 N = 353 N =244 0.001 0.001 0.001 0 5 10 15 20 25 0 5 10 15 20 25 0 5 10 15 20 25 Porosity (% BV) Porosity (% BV) Porosity (% BV)

1000 1000 Non-Fractured 1000 Fractured 100 100 100

10 10 10

1 1 1

T-220 0.1 0.1 0.1 T-220 T-220 Upper Visean (Tula) Permeability (md) Permeability (md) Permeability (md) Middle Visean (Oksky) Lower Visean (Oksky) N = 44 0.01 N = 140 0.01 N = 246 0.01

0.001 0.001 0.001 0 5 10 15 20 25 0 5 10 15 20 25 0 5 10 15 20 25 Porosity (% BV) Porosity (% BV) Porosity (% BV) BITUMENBITUMEN ANDAND POROSITYPOROSITY 10

100% 75% 9 T-220 Filled Filled All Data 8 N = 1,420 CorrectedData 7

3 Bitumen (vol. % of Rock) of % (vol. Bitumen

5% 1 Filled

0 0 5 10 15 20 25 P otential Porosity (% BV) BASHKRIANBASHKRIAN RESERVOIRRESERVOIR QUALITYQUALITY ANDAND MINERALOGYMINERALOGY 4070

Artinskian Moscovian (?) B1 4090

4110

4130

Calcite Quartz Feldspar B4 4150 Dolomite Clay

4170 S1 Porosity (% BV) Perm. (m d) Bitumen (% BV)

0 5 10 15 20 25 0204060801000 20406080100

Volume (% BV) Abundance (wt.%) Abundance (wt.% ) Permeability (md) SERPUKHOVIANSERPUKHOVIAN RESERVOIRRESERVOIR QUALITYQUALITY ANDAND MINERALOGYMINERALOGY

4160 B4

4180

4200

S3 4220

4240

S4 Calcite Quartz Feldspar 4260 Dolomite Clay

4280 Porosity (% BV) Perm. (m d) VO1 Bitumen (% BV)

0 5 10 15 20 25 0 204060801000 20406080100 Volume (% BV) Abundance (wt.%) Abundance (wt.% ) Perm eability (m d) UPPERUPPER VISEANVISEAN RESERVOIRRESERVOIR QUALITQUALITYY ANDAND MINERALOGYMINERALOGY

4270 S4

VO1 4290

4310 VO2

4330

VO3

4350

Calcite Quartz VO4 Porosity (% BV) Feldspar Perm. (md) Bitumen (% BV) Dolomite Clay 4370 0 5 10 15 20 25 0 204060801000 20406080100

Volume (% BV) Abundance (wt.%) Abundance (wt.% ) Permeability (md) UPPERUPPER VISEANVISEAN RESERVOIRRESERVOIR QUALITYQUALITY ANDAND MINERALOGYMINERALOGY

4350 VO3

4360

VO4

4370

4380

VO5 4390

4400

VO6 4410

4420 Calcite Quartz VO7 Porosity (% BV) Feldspar Perm. (md) Bitumen (% BV) Dolomite Clay 4430 0 5 10 15 20 25 0 20406080100020406080100

Volume (% BV) Abundance (wt.%) Abundance (wt.% ) Permeability (md) UPPERUPPER VISEANVISEAN RESERVOIRRESERVOIR QUALITQUALITYY ANDAND MINERALOGYMINERALOGY

4410 VO6

VO7 4430

4450 VO8

4470

4490

VO9 4510

Calcite Quartz VT1 4530 Porosity (% BV) Feldspar Perm. (md) Bitumen (% BV) Dolomite Clay

0 5 10 15 20 25 0204060801000 20406080100

Volume (% BV) Abundance (wt.%) Abundance (wt.% ) Perm eability (md) STRATIGRAPHYSTRATIGRAPHY ANDAND WIRELINEWIRELINE PRESSURESPRESSURES Logs Core Wireline Pressure

Major Flow Barriers Minor Flow Barriers PLATFORMPLATFORM POROSITYPOROSITY DISTRIBUTIONDISTRIBUTION

CYCLES PLATFORMPLATFORM POROSITYPOROSITY DISTRIBUTIONDISTRIBUTION

CYCLES WELLWELL TIETIE TOTO 3D3D SEISMICSEISMIC T-10 z T-17 z 5,8005,800 0 5,60 T-41 z ,400 5 0 5,20 ,000 T-40 T-9 5 00 z T-103 z 4,8 0 4,60 z T-8 ,400 4 T-102 z T-1K z T-108 T-42 z T-7 z z z z T-6 T-107 T-1100 T-1101 z z T-39 z T-16 T-43 z T-419 T-1 T-3K T-4 T-38 z z z T-5050 z z z z z T-106 T-70 T-5 z T-320 z T-72 z z z T-105 z T-113 z T-112 T-118 T-11 z KEY T-20 z T-15 z KEY T-111 T-24z z z T-117 z T-104 z T-318z z T-110 z T-5K T-19 T-317 z z z z T-14 z T-116 T-122 T-37 T-109 T-115z T-220 z T-27 T-26 FLANK z T-220 T-121 z FLANK z T-44 z z T-21 z z T-22 zT-100 T-114 z T-120 z z z T-25 T-119 z WELLWELL z T-28 T-124 T-23 T-29 z z z z T-12 T-123 z z TT-47-47 North z T-30 z T-31 z T-34 z

4,200 T-45 Tengiz Reservoir z 4,400 4,600 Top Bashkirian (m) 4,800 5,000 012 5,200 5,400 Kilometers 5,600 KEYKEY FLANKFLANK WELLWELL

KUNGURIAN SALT

ANHYDRITE

ARTINSKIAN PLATFORM

FLANK FLANKFLANK DEVELOPMENTDEVELOPMENT

TOP BASH

PLATFORM FLANK

TOP DEV FlankFLANK Wells InteriorPLATFORM Wells Highstand Facies

Packstone with Crinoids, Brachiopods, and Locally Reef Mounds Deposition on Slope Deep Platform

Lowstand Facies

Karst Calcrete Non-Deposition

Subaerial Exposure

Minor Deposition on Slope OUTCROPOUTCROP OFOF PLATFORMPLATFORM FLANKFLANK

ASTURIAS, SPAIN FLANKFLANK FACIESFACIES DISTRIBUTIONDISTRIBUTION

BOUNDSTONE AND GRAINSTONE

DETRITAL BRECCIA DEPOSITIONALDEPOSITIONAL MODELMODEL FORFOR SLOPESLOPE STRATIGRAPHYSTRATIGRAPHY ANDAND ROCKROCK TYPETYPE

All Tengiz-47 Mudstone Artinskian W ackestone P/W'stone Bashkirian Packstone Serpukhovian G/P'stone Visean (Oksky) Grainstone Visean (Tula) Breccia/Rudstone Devon. Shallow Devonian Deep

0% 20% 40% 60% 80% 100% SLOPESLOPE BOUNDSTONEBOUNDSTONE ANDAND CLASTSCLASTS

CLASTS

BOUNDSTONE LOWERLOWER SLOPESLOPE PACKSTONESPACKSTONES

SILICA REPLACEMENT

FRACTURE SLOPESLOPE RESERVOIRRESERVOIR QUALITYQUALITY

100

10 Fractured

0.1

Permeability (md) Permeability Bashkirian 0.01 Serpukhovian Visean (Oksky) 0.001 Visean (Tula) 0 3 6 9 12 15 Porosity (%) 9 BITUMENBITUMEN ANDAND POROSITYPOROSITY

All Tengiz-47 100% Filled Bashkirian 6

30% Filled 3 Bitumen (vol.%)

10% Filled

0 03691215 Potential Porosity (%) LOGS CORE PYRITE Bashkirian DOLOM CGR SIDER Serpukhovian 0 200 SGR CALCITE 0 200 BARITE

Visean (Oksky) V SLOPESLOPE Slope Debris

DIAGENESISDIAGENESIS Visean (Tula) Slope

BURIAL Devonian (HYDROTHERMAL?) Platform DOLOMITE Quartz SILICA Clay BARITE Barite URANIUM

0 1020304050

Abundance (wt.%) FRACTURESFRACTURES ANDAND VUGSVUGS

SOLUTION-ENLARGED FRACTURES VUGSVUGS ININ FLANKFLANK WELLSWELLS

FBSTB_DSSTB_S_1.C2_1 WIRE.PEFL_1 150MM 275 919 FBSTB_DSSTB_S_1.C1_1 WIRE.AT90_2 150MM 275 2 2000 WIRE.HCGR_3 WIRE.CMRP_3MS_2 IMAGE_STATIC.IMVI DEPTH IMAGE_DYNAMIC.IMVI 0GAPI 150 0.3 0 METRES WIRE.HSGR_2 WIRE.PHIX_DN_1 0GAPI 150 0.3 0

4556

4557

Large Vug FRACTURESFRACTURES ININ FLANKFLANK WELLSWELLS

FBSTB_DSSTB_S_1.C2_1 WIRE.AT90_2 150MM 275 2 2000 FBSTB_DSSTB_S_1.C1_1 WIRE.PEFL_1 150MM 275 919 WIRE.HCGR_3 WIRE.CMRP_3MS_2 IMAGE_STATIC.IMVI DEPTH IMAGE_DYNAMIC.IMVI 0GAPI 150 0.3 0 METRES WIRE.HSGR_2 WIRE.PHIX_DN_1 0GAPI 150 0.3 0

4516

Fractures FRACTURESFRACTURES ININ FLANKFLANK WELLSWELLS

4576

4577

Fracture with whole mud invasion TENGIZTENGIZTENGIZ AND ANDAND KOROLEV KOROLEVKOROLEV

STRATIGRAPHIC FRAMEWORK

RESERVOIR QUALITY

4576

4577 SUMMARYSUMMARY POINTSPOINTS

•• CarboniferousCarboniferous IsolatedIsolated CarbonateCarbonate PlatformsPlatforms withwith SteepSteep FlanksFlanks •• PlatformPlatform GrowthGrowth ViewedViewed inin SequenceSequence StratigraphicStratigraphic ContextContext •• ReservoirReservoir QualityQuality inin PlatformPlatform ControlledControlled byby StratigraphyStratigraphy andand LimitedLimited DiagenesisDiagenesis •• ReservoirReservoir inin FlanksFlanks RelatedRelated toto FracturingFracturing andand DiagenesisDiagenesis