6_MOGI_Gilio_Presentation Stage 2009 Thin Oil Rim Development

Master in Petroleum Engineering 2008-09

Thin Oil Rim Development Author: Francesco Gilio

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Master in Petroleum Engineering 2008-09

Stage Subject  Thin Oil Rim Development  Author

Company Tutors

Ing. Francesco Gilio 

Ing. Carlo Monico  Dott.  Alberto Cominelli  Universit University y Tutor Prof. Ing. Francesca Verga 

Division

Exploration & Production 

Dept.

MOGI/IPET 

San Donato Milanese 20-21-22 October 2009

2

Master in Petroleum Engineering 2008-09

Stage Subject  Thin Oil Rim Development  Author

Company Tutors

Ing. Francesco Gilio 

Ing. Carlo Monico  Dott.  Alberto Cominelli  Universit University y Tutor Prof. Ing. Francesca Verga 

Division

Exploration & Production 

Dept.

MOGI/IPET 

San Donato Milanese 20-21-22 October 2009

2

List of Content Stage Subject  Thin Oil Rim Development



Project Scope



Reservoir Reservo ir Description



Wells Definition



Local Grid Refinement



Scenario 1



Scenario 2



Conclusions

3

Project Scope

Investigation on the use of horizontal well to develop a thin oil rim in an actual field through numerical simulation

The purpose was to optimize the horizontal well by means of sensitivity analysis, considering different development scenarios

4

List of Content Stage Subject  Thin Oil Rim Development



Project Scope



Reservoir Description



Wells Definition



Local Grid Refinement



Scenario 1



Scenario 2



Conclusions

5

Reservoir Description - General information • Off shore condition • Two culminations (E2 and E4) • Carbonate sequence with different formation characteristics • Huge gas cap (very rich condensate fluid) • Strong aquifer • Saturated oil (34 °API) forming thin oil rims

G

• 17 m oil column

O W

E4 Development fluids scenarios: •

oil – only

•

oil – gas

E2

6

Reservoir Description - Simulation Modeling

Full-field black oil model had been devised to study both culminations

A sector model was defined in a representative area of E2

7

List of Content Stage Subject  Thin Oil Rim Development



Project Scope



Reservoir Description



Wells Definition



Local Grid Refinement



Scenario 1



Scenario 2



Conclusions

8

Oil Well Definition Horizontal Well bore diameter: 0.625 ft Cased hole completion Tubing: 3” 1/2

Production constraints Sensitivities

- Control

⇨

Oil rate

- Depth

- WC max

⇨

70

- Location

- Q gas max

⇨

40x106 scf/d

- Length

- Q liquid max

⇨

4500

stb/d

- Oil Rate

- THP min

⇨

600

psia

- Direction

- Q oil min

⇨

100

stb/d

%

9

Gas Well Definition Vertical Well bore diameter: 0.625 ft Open hole completion Tubing: 4” 1/2

Production constraints

- Control THP

⇨

600

psia

- WGR max

⇨

0,2

stb/103scf 

- Q gas max

⇨

40x106 scf/d

- Q gas min

⇨

5x106

scf/d

10

List of Content Stage Subject  Thin Oil Rim Development



Project Scope



Reservoir Description



Wells Definition



Local Grid Refinement



Scenario 1



Scenario 2



Conclusions

11

Local Grid Refinement - Simulation Grid Size Investigation Different local grid refinements (LGR) sensitivities around a generic horizontal well Original grid size: • Horizontal

200 X 200 m

• Vertical

2 ÷ 10 m

G

LGR splits

O

• Horizontal

2, 4, 5

• Vertical

2, 4, 6

W

12

Local Grid Refinement - Choice Of Best LGR Based on simulation results & CPU time 200X200

3

finer grids

100X100

4

Cumulative Oil Production

Local Grid Refinement

  s   r   u   o    h   e   m    i    T    U    P    C

   b    t    S    6    0    1

40X40

50X50

Z/6

100X100

Z/4 Z/4

Z/2

Z/2

200X200

0

20

Years

LGR

⇨

0 LGR Split Type

50 X 50 m & z/2 13

List of Content Stage Subject  Thin Oil Rim Development



Project Scope



Reservoir Description



Wells Definition



Local Grid Refinement



Scenario 1



Scenario 2



Conclusions

14

Scenario 1 / Oil Development – Well Direction

Well A

Well C

Well B

G O

Well dedicated LGRs

W

15

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Scenario 1 – Well A Length Sensitivities Cumulative Oil Production

5

   b    t    S    6    0    1

G

0

Years

20

O W

Recovery Comparison G

1

Range

⇨

200

÷

optimal length

⇨

oil recovery

⇨

2000 m

1000 m 4,0 x 106 Stb

  x   a   m    F    R    /    F    R

O W

0.3 0

500

1000

1500

2000

Length (m)

18

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Scenario 1 – Well B Same workflow was applied to well B

⇨

orthogonal direction

depth

⇨

8365 ft

location

⇨

optimized

length

⇨

600 m

oil rate

⇨

1500 ÷ 2000 Stb/d

oil recovery

⇨

3,3 x 106 Stb

20

Scenario 1 – Well C Same workflow was applied to well C

⇨

diagonal direction

depth

⇨

8365 ft

location

⇨

optimized

length

⇨

1000 m

oil rate

⇨

1500 ÷ 2000 Stb/d

oil recovery

⇨

4,2 x 106 Stb

21

Scenario 1 – Direction & Length Comparison Total Oil Recovery

5

Well C

4

Well B

   b    t    S    6    0    1 3

Well A

Well C Well B 2

Well A

0

500

1000

1500

2000

Length (m)

Well C • Highest recovery for any length • Less length sensitive

22

List of Content Stage Subject  Thin Oil Rim Development



Project Scope



Reservoir Description



Wells Definition



Local Grid Refinement



Scenario 1



Scenario 2



Conclusions

23

Scenario 2 / Oil + Gas Development

horizontal oil well gas well

⇨

oil well

⇨

fixed

vertical gas well Well B

same workflow as scenario 1

Well C

Well A

Sensitivities •

Depth

•

Location

G

•

Length

O

•

Oil Rate

W

•

Direction

24

Scenario 2 – Well A Depth Sensitivities

2

Cumulative Oil Production

   b    t    S    6    0    1

G

1

  x   a   m    F    R    /    F    R

Well Shut-in

Recovery Comparison

O

W

Increasing Depth

0

0.8

10

20

Years

8350

8360

8370

8380

Depth (ft)

optimal depth

⇨

8370 ft

oil recovery

⇨

1,7 x 106 Stb

25

Scenario 2 – Well A Location Sensitivities

3

Recovery Comparison

Cumulative Oil Production 1

peripheral    b    t    S    6    0    1

original

  x   a   m    F    R    /    F    R

crestal

W O

G

0

0

Years

20

-1200

-600

0

600

Shift (m)

optimal location

⇨

600 m SW

oil recovery

⇨

2,3 x 106 Stb

26

Scenario 2 – Well A Length Sensitivities Cumulative Oil Production

Recovery Comparison

3

G

1

   b    t    S    6    0    1

O W

  x   a   m    F    R    /    F    R

1200 m 1400 m 1600 m

0

20

Years

0 0

500

1000

1500

2000

Length (m)

Length

⇨

200

÷

2000 m

optimal length range

⇨

oil recovery

⇨

1200 – 1600 m 2,3 – 2,5 x 106 Stb

27

Scenario 2 – Well A Oil Rate Sensitivities Rate

⇨

500

Length

⇨

1200, 1400 & 1600 m

÷

4000 Stb/d

Total Oil Recovery 3

1200 m 1400 m

   b    t    S    62    0    1

1600 m

highest recovery

1 0

1000

2000

3000

4000

Rate (Stb/d)

(Total Oil Recovery) 2 / Time

Total Oil Recovery / Time

1

2.4

0.8

   b    t0.6    S    3    00.4    1

slow recovery

   b    t1.6    S    9    0    10.8

less performing

0.2

0

0 0

1000

2000

3000

Rate (Stb/d)

4000

0

1000

2000

3000

4000

Rate (Stb/d)

28

Scenario 2 – Well B Same workflow was applied to well B

⇨

orthogonal direction

depth

⇨

8365 ft

location

⇨

optimized

length

⇨

800 m

oil rate

⇨

1500 ÷ 2000 (Stb/d)

oil recovery

⇨

1,8 x 106 Stb

29

Scenario 2 – Well C Same workflow was applied to well C

⇨

diagonal direction

depth

⇨

8365 ft

location

⇨

optimized

length

⇨

2000 m

oil rate

⇨

1500 ÷ 2000 (Stb/d)

oil recovery

⇨

2,5 x 106 Stb

30

Scenario 2 – Direction & Length Comparison

Oil Rim Recovery 3

Well B

Well C

   b    t    S    6 2    0    1

Well A

Well C

Well A

Well B

Max Technical Length

1 0

1000

2000

3000

Length (m)

• Well A gives higher recovery than C in the range 1200 – 1600 m • Highest recovery at 2000 m for well C and 1600 m for well A 31

List of Content Stage Subject  Thin Oil Rim Development



Project Scope



Reservoir Description



Wells Definition



Local Grid Refinement



Scenario 1



Scenario 2



Conclusions

32

Conclusions • Thin oil rim exploitation through horizontal well was studied considering two development scenarios: oil-only and oil + gas • Sensitivities were performed with reservoir sector model on direction, depth, location, length and oil rate • Oil recovery increases with distance of well from gas cap • Locations close to WOC or too peripheral lead to reduction in oil recovery due to high water production • Simultaneous gas and oil development leads to earlier shut-in due to faster depletion, aquifer reaction and consequent water arrival • Oil only scenario gives 70-80% more recovery and requires shorter horizontal intervals for all directions • Diagonal direction allows oil recovery being less length sensitive in case of oil only development • Optimal position minimizes gas production and limits water arrival • Maximum oil recovery obtained in case of oil only development through diagonally oriented 1000 m horizontal interval and 1500-2000 Stb/d oil rate

33