Selim S. Shaker

Geopressure Analysis Services

(G.A.S.)

1

GEOPRESSURE

Pore Fluid Rock Mechanics

Overburden

Pore Pressure Stresses

Tectonic

2 G.A.S.

IS MS

Deposition, Basin subsidence, Tectonic and

Stresses magnitude and path history

Tectonic

Courtesy of TGS Ad

Geology of Stresses

PS

PS, IS and MS are Principal, Intermediate and Minimum Stresses

PS

S 1

S 2

S 3

3 G.A.S.

Pressure

PS H PP FP

Predicted PP Measurable PP Fracture pressure

Subsurface Geopressure Profile

G.A.S. 4

Rocks, Fluids and Stress

Unconfined Hydrodynamic

Confined Geopressured

Pressure

PS H PP FP

Geopressure Drilling Tolerance Window ( DTW)

MW pressure

TOG Top of

Geopressure

Predicted PP Measurable PP Mud Pressure

DTW

G.A.S. 5

Safety Limit

6

TOG

Csg

Csg

Csg

Csg

Csg

Csg

Mud Line (sea floor)

A A

DTW

Csg

G.A.S.

Shallow vs. Deep Water PP profiles:

DTW

Impact of Mud line depth on DTW:

W.D.= 7000’

Oil vs. Gas entrapment

7 Challenges due to Transgression and Regression

VK 1001

9000

9500

10000

10500

11000

11500

12000

12500

13000

13500

4000 4500 5000 5500 6000 6500 7000 7500 8000

Pressure (RFT)

Depth

PP Hydro

MW pressure

Loss of circulation

Kicks can lead to Blow out

H

P Transgression

P Regression

Impact of P Transgression (T) and P Regression ( R ) on DTW:

G.A.S.

8

MC 809 #1

16000

16500

17000

17500

18000

18500

19000

19500

20000

8000 9000 10000 11000 12000 13000 14000 15000

Pressure (psi)

De

pth

(ft

)

GO

M

Oil

GAS

MC 809 #1

16000

16500

17000

17500

18000

18500

19000

19500

20000

8000 9000 10000 11000 12000 13000 14000 15000

Pressure (psi)

De

pth

(ft

)

GO

M

Oil

GAS

MC 809 #1

16000

16500

17000

17500

18000

18500

19000

19500

20000

8000 9000 10000 11000 12000 13000 14000 15000

Pressure (psi)

De

pth

(ft

)

GO

M

Oil

GAS

GB 543 #1

6000

7000

8000

9000

10000

11000

12000

13000

14000

15000

16000

4000 5000 6000 7000 8000 9000 10000

Pressure (psi)

De

pth

(ft

)

GOM

GB 543 #1

6000

7000

8000

9000

10000

11000

12000

13000

14000

15000

16000

4000 5000 6000 7000 8000 9000 10000

Pressure (psi)

De

pth

(ft

)

GOM

+ RFT

Weak Transgression

4000’ in communication

GB 248 #1

16000

17000

18000

19000

20000

21000

22000

8000 9000 10000 11000 12000 13000 14000 15000 16000

Pressure (psi)

De

pth

(ft

)

GO

M

+ RFT

Regression

Strong Transgression (T)

Weak (T)

Transgression and Regression

G.A.S.

9

Grant EB 654#1

Pore Pressure Prediction from Seismic

4000

6000

8000

10000

12000

14000

16000

7 9 11 13 15 17 19

Pressure (EMW)

De

pth

(ft)

OB ppg PP ppg MW ppg

LOT ppg Calc LOT ( Frac)

Salt Base

PT

G.A.S.

Well abandonment in DW due to the proximity of Mud and Formation Pressures

F-K-B

Csg

10

Grant's Flow -Kill- Breakdown @ 10358'

8.00

9.00

10.00

11.00

12.00

13.00

14.00

15.00

31-Oct 05-Nov 10-Nov 15-Nov 20-Nov 25-Nov 30-Nov 05-Dec

MW

E

MW Flow Kill LC Ballooning

Flow – Kill – Breakdown (LOC)

FKB Cycle M

W p

pge

G.A.S.

compartmentalization based on MPP

0il

VK 912#1

9000

9500

10000

10500

11000

11500

12000

12500

13000

13500

4000 6000 8000 10000

PP (RFT)

Depth

PP (RFT) Hydrostatic

OIL

Competent Seal

Breached Seal

Compartmentalization and Sealing Capacity :

R

T

T

11 G.A.S.

0

2000

4000

6000

8000

10000

12000

14000

16000

18000

0 2000 4000 6000 8000 10000 12000 14000

MC 296

FP GOM Hydro Lithostatic

CSG LOT ECD psi

10900

10950

11000

11050

11100

11150

11200

11250

11300

11350

11400

4000 5000 6000 7000 8000 9000 10000

MC 296

Formation P Mud P RFT ECD psi

CSG LOT GOM Hydro

Lithostatic Fracture Pressure

DTW

The Impact of HYDROCARBON on the DTW

The thick gas column led to more reduction of the DTW

Immediate south of DW Horizon block MC 252 (BP Deep Horizon)

Mississippi Canyon 296 (ENI)

G.A.S. 12

MC 252, Texaco

G-18207 Well #1 ST#2

13 G.A.S.

4000

6000

8000

10000

12000

14000

16000

18000

20000

8 10 12 14 16 18PP MWE

MW, LOT, Csg of DW Horizon( Information in Public Domain)

DW Horizon ppg MW DW Horizon ppg LOT

CSG Ltho ppg

Hydro ppg

0

2000

4000

6000

8000

10000

12000

14000

16000

18000

0 5000 10000 15000

Texaco - BP Deepwater Horizon MC 252

Formation P Lithostatic

GOM Hydro CSG

ECD psi Deepwater Horizon LOT-FIT

The narrow DTW on Mississippi Canyon 252 ( Deep Horizon BP)

The Narrow DTW in addition to the presence of hydrocarbon led to serious drilling challenges

DTW

G.A.S. 14

15

St. Malo

Jack

Atlantis

Chinook Cascade

Mad Dog

Mississippi Delta

Walker Ridge

Mississippi Canyon

Gulf of Mexico

Frontier Exploration

Discoveries

Subsalt Wells

Sigsbee

Escarpment

Shelf Edge

K C

Hadrian

Neogene

Paleogene

The Impact of Dirty Salt on the DTW

G.A.S.

16

Stresses models (generic)

(due to low salt density and very low permeability)

2.3 g/cc @ 20 %

porosity

1.9 g/cc LOW DENSITY

Resultant

Vector

Impermeable

G.A.S.

17

Principal Stress vs. Overburden in Salt Basins

(due to salt perturbation)

Diapirism / Buoyancy

OB (Overburden)

SS (Shear Stress)

PS ( Maximum

Principal Stress)

Sediments

load

Pre-Salt Sediment G.A.S.

18

Modified after Rowan 1999

Frontier GOM

Discoveries

The Salt Toe at Sigsbee frontier plays

G.A.S.

19

PS

Early Tertiary

(Wilcox)

Modified after Chowdhury and Lopez-Mora, 2004

OB=FP

Slow Moving Buried Salt

G.A.S.

PS = TS

MS= OB

IS

TS= Tectonic Stress

20

OB+WC

Gouge

SB

Geopressured

Normally Pressured

FP

P S

PP

Tertiary Salt Toe Belt

New Discoveries

Rafted sediments

Mud Line

A

Pre salt PP

Top of Geopressure

SS

Geopressure

Model of Salt Toe

G.A.S.

0

5000

10000

15000

20000

25000

30000

8 9 10 11 12 13 14 15 16 17

De

pth

P ppg mwe

Chevron - Jack - WR 759 # 1

LOT/FIT OB+WC ppg ECD ppg

Casing RFT ppg mwe

Dirty Salt

Gouge zone

DTW

Calculated Fracture Pressure Chevron Jack #1

P-D Plot

ppg mwe

G.A.S. 21

Paleogene

22

18

Rafted Sediments

Jack at the base of salt

No Mud Return

(Gouge)

Jack in middle of salt

G.A.S.

Jack #1 Mud log

0

5000

10000

15000

20000

25000

30000

8 9 10 11 12 13 14 15 16 17

De

pth

P ppg mwe

Chevron - Malo - WR 678 #1

OB+WC ppg MW ppg LOT/FIT ppg Casing

`

Gouge zone ?

DTW

Clean Salt

Calculated Fracture Pressure Chevron

St. Malo #1

P-D Plot ppg mwe

G.A.S. 23

0

5000

10000

15000

20000

25000

30000

8 9 10 11 12 13 14 15 16 17

De

pth

P ppg mwe

Chevron - Jack - WR 759 # 1

LOT/FIT OB+WC ppg ECD ppg

Casing RFT ppg mwe

Dirty Salt

Gouge zone

DTW

Calculated Fracture Pressure

0

5000

10000

15000

20000

25000

30000

8 9 10 11 12 13 14 15 16 17

De

pth

P ppg mwe

Chevron - Malo - WR 678 #1

OB+WC ppg MW ppg LOT/FIT ppg Casing

`

Gouge zone

DTW

Clean Salt

Calculated Fracture Pressure

Jack vs. St. Malo Discoveries

G.A.S. 24

0

2000

4000

6000

8000

10000

12000

14000

16000

18000

20000

22000

8 10 12 14 16 18

Pressure MWE

BP - Atlantis - MC 699 #1

MW LOT-FIT Csg PS mwe

Dirty Salt

Gouge zone

Calculated Fracture Pressure

DTW

FKB

BP

Atlantis #1

P-D Plot ppg mwe

G.A.S. 25

Challenges: LOC @salt base Csg in Salt Several Bypass & ST

Neogene

0

5000

10000

15000

20000

25000

30000

8 10 12 14 16 18

Pressure MWE

Exxon - Hadrian - KC919 #1

MW LOT-FIT Csg PS mwe MDT ppg

Gouge zone

Clean Salt

Calculated Fracture Pressure

DTW

Hadrian #1

P-D Plot ppg mwe

G.A.S. 26

0

5000

10000

15000

20000

25000

30000

8 10 12 14 16 18

Pressure MWE

Exxon - Hadrian - KC919 #1

MW LOT-FIT Csg PS mwe MDT ppg

Gouge zone

Clean Salt

Calculated Fracture Pressure

DTW

Atlantis vs. Hadrian Discoveries

G.A.S. 27

0

2000

4000

6000

8000

10000

12000

14000

16000

18000

20000

22000

8 10 12 14 16 18

Pressure MWE

BP - Atlantis - MC 699 #1

MW LOT-FIT Csg PS mwe

Dirty Salt

Gouge zone

Calculated Fracture Pressure

DTW

FKB

28

Deposits geometry and facies changes

Pressure

Velocity (Porosity Index)

Pressure Transgression

Pressure Regression

Communication

Proposed Mud pressure

A

The importance of integrating the

prospect ‘s geological building blocks with Seismic PP Predictions:

Predicted Seal Pressure

Reservoir Pressure

Seal – Reservoir Interface

1

2

3

4

G.A.S.

Effective Seal Macaroni Breach zone

Mt.Massive

Increase of PS (Auger)

Decrease of PS (GC 908)

Salt emplacement and displacement impact on geopressure setting and Risk Assessment

29 G.A.S.

P-D (PPP Sand & Shale)

0

5000

10000

15000

20000

0 2000 4000 6000 8000 10000 12000 14000 16000 18000

P

D

Overburden Hydrostatic PPP Shale MW RKB

PP RFT MW RFT LOT

G.A.S.

P-D KC 255

0

5000

10000

15000

20000

0 2000 4000 6000 8000 10000 12000 14000 16000

P

D

Overburden Hydrostatic PPP Shale

PP RFT MW RFT LOT

Pore Pressure Prediction Modeling Challenges

30

KMG 602#1

10000

10200

10400

10600

10800

11000

11200

11400

11600

11800

12000

4000 5000 6000 7000 8000 9000 10000 11000

P

D

Hydrostatic OB psi PPP psi Shale

PP psi Sand MW psi RKB

KMG 602#1

10000

10200

10400

10600

10800

11000

11200

11400

11600

11800

12000

4000 5000 6000 7000 8000 9000 10000 11000

P

D

Hydrostatic OB psi PPP psi Shale

PP psi Sand MW psi RKB

SIP

SIP

Challenges of PPP Model Calibration in a pay zone ?

G.A.S.

31

Conclusions

Factors Reduce DTW

P T and PR cause the disparity between seal and reservoir pressures

Bore hole instability, bypasses, side tracks , F-K-B cycle , possible blow-out, and failure

to reach the prospective target are common in Deepwater due to the narrow DTW.

Establishing the geological building blocks for geopressure prediction goes hand in hand

with prospect generation and forecasts drilling challenges.

The most troublesome spots along the bore hole trajectory is the seal – reservoir interface.

Pore pressure is predicted in seals and measurable in reservoirs.

The DTW ( FP – PP) window size dictates feasible prospect’s drilling prognosis.

Increase of water depth to the sea floor (mud line) reduces the DTW

Hydrocarbon column reduces DTW

G.A.S.

Dirty Salt educes DTW

32

Oil vs. Gas in Deep Water

Prediction’s Model Calibration challenges

Thank you

33 G.A.S.