COMPARISON BETWEEN KENYA TERTIARY RIFT AND LIAODONG BAY DEPRESSION 11th Africa Oil & Gas, Trade & Finance Conference & Exhibition Kenya 2007 23 th -25

COMPARISON BETWEEN COMPARISON BETWEEN

KENYA TERTIARY RIFT AND KENYA TERTIARY RIFT AND

LIAODONG BAY LIAODONG BAY

DEPRESSIONDEPRESSION

11th Africa Oil & Gas, Trade & Finance Conference & Exhibition Kenya 2007

23th-25th May 2007 Nairobi, Kenya

11th Africa Oil & Gas, Trade & Finance Conference & Exhibition Kenya 2007

23th-25th May 2007 Nairobi, Kenya

Wu Keqiang

Senior Geologist

Research CNOOC

Beijing China

Tel: 010-84525363

Email: [email protected]

NOT AN OFFICIAL UNCTAD RECORDNOT AN OFFICIAL UNCTAD RECORD

2

ACKNOWLEDGEMENTSACKNOWLEDGEMENTS

Colleagues at CNOOC

CNOOC International Limited

Science and Technology Development

Department, CNOOC

Research CNOOC

11th Africa Oil & Gas, Trade & Finance

Conference & Exhibition

3

Introduction of Kenya Tertiary Rift

and Liaodong Bay Depression

Petroleum Geological Comparison

of Kenya Tertiary Rift and Liaodo

ng Bay Depression

Advice and Conclusion

OUTLINEOUTLINE

4

Introduction of Kenya Tertiary Rift and Liaod

ong Bay Depression- Location and Exploration- Why Liaodong Bay Depression

Petroleum Geological Comparison of Kenya

Tertiary Rift and Liaodong Bay Depression


OUTLINEOUTLINE

5

The Location of Kenya Tertiary RiftThe Location of Kenya Tertiary Rift

Kenya Tertiary Rift Kenya Tertiary Rift locates in the western part of Kenya, develops in the locates in the western part of Kenya, develops in the eastern branch of the East African Rift System.eastern branch of the East African Rift System.

6

The Exploration Statue of Kenya Tertiary RiftThe Exploration Statue of Kenya Tertiary Rift

O IL A N D G A S SHO W

D RILLED & A BA N D O N ED WELLO IL SEEPO IL SHO W

G A S SHO W O IL A N D G A S SHO W

D RILLED & A BA N D O N ED WELLO IL SEEPO IL SHO W

G A S SHO W

FRONTIER AREAFRONTIER AREA

Aera : 38,904 kmAera : 38,904 km22

Wells : 2 Wells : 2

Seismic 2-D: 7,652 km Seismic 2-D: 7,652 km

Loperot 1: located in the southern part of the Lokichar Trough.

Encountered two lacustrine shale intervals with very good source rock potential.

Recovered some 9 liters of 29° API crude during a DST.

Eliye Springs 1: was drilled in the southwestern part of the Turkana Graben. The well was abandoned as dry.

Loperot 1

Eliye Springs 1

From nation oil corporation of Kenya

7

The Loacation of Liaodong Bay DepressionThe Loacation of Liaodong Bay Depression

BOHAI BAY BASIN

LIAO

DONG

BAY D

EPRESSION

Liaodong Bay DepLiaodong Bay Depression (LBD) ression (LBD)

locates on the northern locates on the northern part of Bohai bay basin, part of Bohai bay basin, China, covers an area abChina, covers an area about 15,300 square kilomout 15,300 square kilometers. eters.

8

The Exploration Statue of Liaodong Bay DepressionThe Exploration Statue of Liaodong Bay Depression

JZ31-6

120 exploratory and delineation w

ells were drilled, 79 wells got oil fl

ow, 9 oil & gas fields and 19 oil be

ared structures have been discov

ered. The geological success rate

is 66%.

Aera : 15300 kmAera : 15300 km22

Wells : 120Wells : 120

Seismic 2-D: 18,000km Seismic 2-D: 18,000km

9

Analog, why LBD?Analog, why LBD?

Comparative analysis is the most popular way at the beginning

of studying a frontier area. 3 reasons exit, why Choosing the Lia

odong Bay Depression (LBD) as the analog to compare with KT

R.

Basin type is similar-riftShape is similar-stripeFramework of basin is similar-half grabens

Comparing the basin origin, the petroleum geology and accumul

ation process of KTR with LBD, may obtain several good advice

s and ideas for exploration in KTR.

10

Tan-Lu fault system

Liaodong Bay Depression

Xu Shouyu,2005

The Basins TypeThe Basins Type

Kenya tertiary rift, is a new episode succeeded the Cretaceous-Paleogene one. This mainly N-S trending rifting phase has active since the Eocene and is responsible for the creation of a string of half graben sub-basins.

Liaodong Bay Depression sits astride the Tan-Lu fault system of eastern China, one of the world's largest strike-slip fault systems.


11

The Basin ShapeThe Basin Shape

Basin Boundary Tan-lu fault

AB section

Shore line

rise sag

①

②③

④⑤

① Liaoxi sag ② Liaoxi rise ③ Liaozdong sag

④ Liaodong rise ⑤ Liaozhong sag

A

B

The structure framework of


Both of KTR and LBD are all narrow, elongated system of normal faults.


12

Precanbrian basement

E-E.N1

Liaoxi sagLi

aoxi

Upl

ift Liaozhong sag

Lia

od

on

gU

plift

Liaodong sag

Zhang Gongcheng

The structural frameworkThe structural framework

Major extensional faults in the KTR define separate Basins with distinctive structural and geological setting. Five basins are included in KTR, Turkana onshore, Kerio, North Lokichar, Lokichar, South Kerio Trough.

LBD consists of 3 sub-basins(sags) and 2 rises, Liaoxi sag,liaozhong sag,liaodong sag, liaoxi rise, liaodong rise.


13

Introduction to Kenya Tertiary Rift and Liaod

ong Bay Depression


Tertiary Rift and Liaodong Bay Depression- Structure Evolution- source rock- Reservoir and Cap- Habitat of LBD- Geological risks of KTR


OUTLINEOUTLINE

14

LIAODONG BAY

DEPREESION

RIFTING STAGE

Basin

Time

PRESENT

TERTIARY

CRETACEOUSBASEMENT

FAILED

REACTIVE

Late

Early

No or few deposits

Structural EvolutionStructural Evolution

During the tectonic evolution, KTR underwent the rifting stage Only, which may initiat

ed from Eocene, at the end of Neogene, regional uplifting occurred. LBD began its ev

olution in Paleocene, ungerwent 3 stage such as, rifting stage, failed rift stage and rea

ctive stage.


15

The petroleum geology- source rockThe petroleum geology- source rock

Two major lacustrine shale source rock intervals, which were penetrated by Loperot-1, in KTR, aged Miocene and Oligocen

e respectively, are low to high mature.

The major source rock in LBD, is Shahejie Formation, lacustrine shale, which was aged Eocene.

Lokhone shale

Lopreot shale


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ITEMSITEMS KENYA TERTIARY RIFTKENYA TERTIARY RIFT LIAODONG BAY DEPRESSIONLIAODONG BAY DEPRESSION

Age Miocene, Oligocene Eocene

Thickness(m) About 200 About 400-1200

TOC(%) 2.86(Ave.) 1.02-7.69 1.02-2.32

Type of Kerogen

II II

HI 508(Ave.) 186-748 290-454

Lithofacies Lacustrine shale Lacustrine shale

Degree of Maturity

Lokhone:low-Mature

Loperot:Mature to high mature

Mature to high mature

Data Daniel M. Jarvie, 2005 CNOOC


Besides the thickness penetrated by wells, several characters of source rock in KTR

are similar with LBD’s. Some items of KTR are better than LBD’s.

17

0

5

10

15

20

25

30

0 1 2 3 4 5

TOC %（）

S 2mg

/g（

）

poor-non

fair

good

very good

Type I oil proneUsu lacustrine

Type II oil proneUsu marine

Type II/IIIOil/gas prone

Type IIIgas prone

Drygas prone

Leopart1, Lokichar basin（Daniel M. Jarvie, 2005）


0

5

10

15

20

25

30

0 1 2 3 4 5

TOC %（）

S 2mg

/g（

）

poor-non

fair

good

very good

Type I oil proneUsu lacustrine

Type II oil proneUsu marine

Type II/IIIOil/gas prone

Type IIIgas prone

Drygas prone

Leopart1, Lokichar basin（Daniel M. Jarvie, 2005）



From the classification and potential assessment diagram of organic matter, both of organic matters in KTR and LBD, belong to type II, and lot of samples distribute in good to excellent area.

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Source rock in Lokichar basinSource rock in Lokichar basin

Potential generating capacity of Lokhone Shale MePotential generating capacity of Lokhone Shale Member is estimated at 10.5 billion barrels. mber is estimated at 10.5 billion barrels.

Given that about 40% of the shale volume is at mid tGiven that about 40% of the shale volume is at mid to post mature levels this suggests the Lokhone Shalo post mature levels this suggests the Lokhone Shale Member could have generated about 4 billion barre Member could have generated about 4 billion barrels of oil.els of oil.AfterAfter Marine and Petroleum Geology 21 (2004) 63–78Marine and Petroleum Geology 21 (2004) 63–78

Potential generating capacity of Lokhone Shale MePotential generating capacity of Lokhone Shale Member is estimated at 10.5 billion barrels. mber is estimated at 10.5 billion barrels.

Given that about 40% of the shale volume is at mid tGiven that about 40% of the shale volume is at mid to post mature levels this suggests the Lokhone Shalo post mature levels this suggests the Lokhone Shale Member could have generated about 4 billion barre Member could have generated about 4 billion barrels of oil.els of oil.AfterAfter Marine and Petroleum Geology 21 (2004) 63–78Marine and Petroleum Geology 21 (2004) 63–78

Loperot Shale Member, which is mature to high-mature.

Lokhone Shale Member, which is low-mature to mature.


19

The petroleum geology- reservoirs and seals The petroleum geology- reservoirs and seals Reservoir and cap

assemblages

I

II

III

On the base of two shale segments, III reservoir and cap assemblages were identified in KTR. On the base of two shale segments, III reservoir and cap assemblages were identified in KTR.

3 assemblages exit in LBD, E2d, E2-3s, Pre-T(carbonate and volcanic).3 assemblages exit in LBD, E2d, E2-3s, Pre-T(carbonate and volcanic).


20

The oil qualityThe oil quality

KTR:Tested oil ~ 29KTR:Tested oil ~ 29oo API API

(0.883)(0.883)

LBD:heavy oil LBD:heavy oil

API: 17.4API: 17.4o o (Ave.) (Ave.)

API<22.3(0.92): 86%API<22.3(0.92): 86%

The oil quality of KTB is The oil quality of KTB is

better than LBD.better than LBD.


21

The oil habitat of LBD-sourceThe oil habitat of LBD-source, play, play

1. The favorable sag controls the fields distri

bution. About 80% reserves distribute aro

und Liaozhong sag.

2. The favorable assemblage controls the m

ost favorable play. Ed, the major play in L

BD, deposited almost 90% reserves.

Liaoxi sag Liaozhong sag Liaodong sagZhang Gongcheng

Liao

zhon

g sa

g

22

Liaoxi Sag Liaoxi Low Uplift

By Li Weilian

Liaozhong Sag

Liaodong Uplift Liaodong Sag

Fault block

Anticline pool

structural-stratigraphic buried hill pool Turbidite poolLithologicpinchout

4 types of oil accumulation zones:Rise, Steep slope zone, gentle slope zone, Inner grab

en. Almost 90% reserves deposit in gentle zones and rises.

Sand body and fault made up of the major transport system by which oil and

gas charged into the pools. Multiple types of oil pools are found in LBD.

The oil habitat of LBD-zone, poolThe oil habitat of LBD-zone, pool

rise

Gentle

slope

Steep

slope

Inner

sag

23

root mean square(RMS) amplitude of on-horizon slice Zhao Rumin ， 2005

Absorption analysis profile Liu Zhibin ， 2006

Produced 11.7 mmcf/day in DST, (choke: 11.91mm)

Proved gas layer

perspective gas layer

JZ31-6JZ31-6

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The geological risks of KTR- source rockThe geological risks of KTR- source rock

The distribution of two layers source rock is limited.The distribution of two layers source rock is limited.From nation oil corporation of Kenya

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Heat Flow Distribution in KenyaHeat Flow Distribution in Kenya

LokicharLokichar

basinbasin

Anza Anza

basinbasinThe maturity of source rock influenced by local heat flow, such as lava, obviously, it is difficult to identify the range of active pods.


26

The The geological risksgeological risks of Kenya Tertiary Rift of Kenya Tertiary Rift

LOPEROT-1

0

500

1000

1500

2000

2500

3000

3500

4000

W LOKICHAR BASIN

TVK-13 TVK-12

KERIO BASIN NE

BASEMENT

MIDDLE MIOCENE

LOKIC

HA

R FA

ULT

LOKO

NE FA

ULT

LATE MIOCENE TO

QUATERNARY

EARLY TO MIDDLE

MIOCENE

LOKONE SHALE

S

PALEOGENE TO

EARLY M

IOCENE

V V V V

LAVA FLOWV

LATE MIOCENETO PLIOCENE

?

EARLY TOMIDDLE

MIOCENE?

During late Neogene to present, after oil accumulated, regional uplifting and erosion occurred, so another risk is preservation condition.


27

Introduction to Kenya Tertiary Rift and Liaod

ong Bay Depression


Tertiary Rift and Liaodong Bay Depression

Advice and Conclusion- Three step: source-transport-play- The critical technology: seismic

OUTLINEOUTLINE

28

In LBD, ① the favorable oil generating sag (Liaozhong sag) control the oil field di

stribution.

② the favourable reservoir rock and cap rock assemblage (Ed) controls t

he rich-play.

③ The gentle zones and rises controls almost 90% reserves.

④ Multiple oil pools are found in LBD

In the frontier area, such as KTR, according to the exploration pr

ogram and the primary factor controlling the oil distribution of L

BD, 3 points should be noticed during exploration activity.① looking for the favorable basins and grabens

② looking for the favorable reservoir and cap assemblage

③ looking for the favorable oil accumulating zones.

29

The distribution of basins in KTR

5 basins5 basins

Lokichar basin is the Lokichar basin is the best one. best one.

areaarea

thicknessthickness

Source rock layerSource rock layer

Oil seep or showOil seep or show


30

TVK101


31

EROSION Among the three reservoir and cap

assemblages, the lower assemblages

may be the best one.


32

Lava and Seismic technologyLava and Seismic technology

At least two periods volcanics exist in KTR. They covered the dep

osits below them, brought the shielding effect on seismic profiles.

In KTR, the structural framework cannot be divided clearly, the lit

hofacies cannot be identified reliably, because of the shielding ef

fect.


33

Eliminating the shielding effect of lava, can obtain better sei

smic image. Thus the uncertainty and risk during explorati

on process can be decreased. So advanced seismic acqui

sition and processing technology is necessary.

Improve the reliability of sediment facies.

Study the framework of basin.

Improve the reliability of trap interpreted f

rom seismic datas.

34

CONCLUSIONCONCLUSION

Kenya tertiary rift is similar with Liaodong bay depression in basin type, shape and framework.

They are differences in structure evolution and some factors of petroleum geology.

Kenya tertiary rift have good source rocks.

The area of active source rocks and the preservation post oil charging are geological risks for exploration. The latter is the worst one.

The oil habitat of Liaodong bay depression is useful for Kenya tertiary rift during exploration activity. The first step is to identify the favorable generating grabens, then to find the favorable area having good preservation condition.

Improve the seismic quality can decrease the geological risks and costs.

Documents

COMPARISON BETWEEN KENYA TERTIARY RIFT AND LIAODONG BAY DEPRESSION 11th Africa Oil & Gas, Trade & Finance Conference & Exhibition Kenya 2007 23 th -25