6_mogi_gilio_presentation stage 2009 thin oil rim development

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Thin Oil Rim Development

Author: Francesco Gilio

San Donato Milanese 20-21-22 October 2009

Master in Petroleum Engineering 2008-09

2

Stage SubjectThin Oil Rim Development


Author

Ing. Francesco Gilio

Division Exploration & Production

Dept. MOGI/IPET

Company Tutors

Ing. Carlo Monico

Dott. Alberto Cominelli

University Tutor

Prof. Ing. Francesca Verga

Master in Petroleum Engineering 2008-09

3

List of Content


Project Scope

Reservoir Description

Wells Definition

Local Grid Refinement

Scenario 1

Scenario 2

Conclusions

4

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

5

List of Content


Project Scope


Wells Definition


Scenario 1

Scenario 2

Conclusions

6

Reservoir Description - General information

E4

E2

W

G

O

• 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

• 17 m oil column

Development fluids scenarios:

• oil – only

• oil – gas

7

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

8

List of Content


Project Scope


Wells Definition


Scenario 1

Scenario 2

Conclusions

9

Oil Well Definition

Sensitivities

- Depth

- Location

- Length

- Oil Rate

- Direction

Horizontal

Well bore diameter: 0.625 ft

Cased hole completion

Tubing: 3” 1/2

Production constraints

- Control ⇨ Oil rate

- WC max ⇨ 70 %

- Q gas max ⇨ 40x106 scf/d

- Q liquid max ⇨ 4500 stb/d

- THP min ⇨ 600 psia

- Q oil min ⇨ 100 stb/d

1010

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

11

List of Content


Project Scope


Wells Definition


Scenario 1

Scenario 2

Conclusions

12

W

G

O

Local Grid Refinement - Simulation Grid Size Investigation

Different local grid refinements (LGR) sensitivities around a generic

horizontal well

• Horizontal 200 X 200 m

• Vertical 2 ÷ 10 m

Original grid size:

• Horizontal 2, 4, 5

• Vertical 2, 4, 6

LGR splits

13

Local Grid Refinement Choice

0

60

120

180

240

200X200 100X100 - Z/2 50X50 - Z/2 50X50 - Z/4 40X40 - Z/4 40X40 - Z/6

LGR split type

CP

U t

ime

200X200

100X100 - Z/2

50X50 - Z/2

50X50 - Z/4

40X40 - Z/4

40X40 - Z/6

LGR Split Type

CPU

Tim

e h

ours


100X100

50X50

40X40

200X200Z/2

Z/4

Z/6

Z/4

Z/2

0

4

Local Grid Refinement - Choice Of Best LGR

Based on simulation results & CPU time

LGR ⇨ 50 X 50 m & z/2

200X200 finer grids 100X100

0 20

3

Years

10

6 S

tb

Cumulative Oil Production

14

List of Content


Project Scope


Wells Definition


Scenario 1

Scenario 2

Conclusions

15

Scenario 1 / Oil Development – Well Direction

Well A

Well B

Well C

W

G

O

Well dedicated LGRs

16

Scenario 1 – Well A Depth Sensitivities

W

G

O

0.9

1

8350 8360 8370 8380

Depth (ft)

RF /

RF m

ax

Recovery Comparison

G

O

W

Years

10

6 S

tb

0 20

3 Cumulative Oil Production

optimal depth ⇨ 8370 ft

oil recovery ⇨ 2,5 x 106 Stb

Increasing Depth

Ranking based on recovery factors

normalised to maximum values

through the ratio RF/RFmax

17

0

1

-1200 -600 0 600

Shift (m)

RF /

RF m

ax

Recovery Comparison

G

O

W

Scenario 1 – Well A Location Sensitivities

W

G

O

optimal location ⇨ 600 m SW


4

Years

10

6 S

tb

0 20


peripheral

original

crestal

18

0.3

1

0 500 1000 1500 2000

Length (m)

Recovery Comparison

RF /

RF m

ax

G

O

W

Scenario 1 – Well A Length Sensitivities

5

Years

10

6 S

tb

0 20


W

G

O

Range ⇨ 200 ÷ 2000 m

optimal length ⇨ 1000 m


19

0

1

2

3

4

5

0 1000 2000 3000 4000

10

6 S

tb

Rate (Stb/d)

Total Oil Recovery

Scenario 1 – Well A Oil Rate Sensitivities

optimal range ⇨ 1500 ÷ 2000 (Stb/d)

5

Years

10

6 S

tb

0 20


Increasing Rate

Rate ⇨ 500 ÷ 4000 Stb/d

Length ⇨ 600, 1000 & 1400 m

600 m

1000 m

1400 m

20

Scenario 1 – Well B

depth ⇨ 8365 ft

location ⇨ optimized

length ⇨ 600 m

oil rate ⇨ 1500 ÷ 2000 Stb/d


Same workflow was applied to well B ⇨ orthogonal direction

21

Scenario 1 – Well C

depth ⇨ 8365 ft


length ⇨ 1000 m

oil rate ⇨ 1500 ÷ 2000 Stb/d


Same workflow was applied to well C ⇨ diagonal direction

22

2

3

4

5

0 500 1000 1500 2000

Scenario 1 – Direction & Length Comparison

Length (m)

Total Oil Recovery

10

6 S

tb

Well A

Well C

Well B

Well C

Well B

Well A

• Highest recovery for any length

• Less length sensitive

Well C

23

List of Content


Project Scope


Wells Definition


Scenario 1

Scenario 2

Conclusions

24

Scenario 2 / Oil + Gas Development

gas well ⇨ fixed

oil well ⇨ same workflow

as scenario 1

Sensitivities

• Depth

• Location

• Length

• Oil Rate

• Direction

horizontal oil well

vertical gas well

Well A

Well C

Well B

W

G

O

25

10

6 S

tb

0 20

2Cumulative Oil Production

10

Scenario 2 – Well A Depth Sensitivities

Years

Increasing Depth

Well Shut-in

0.8

1

8350 8360 8370 8380

RF /

RF m

ax

Recovery ComparisonG

O

W

Depth (ft)

optimal depth ⇨ 8370 ft


26

Scenario 2 – Well A Location Sensitivities

Years

10

6 S

tb

0 20

3 Cumulative Oil Production

0

1

-1200 -600 0 600Shift (m)

RF /

RF m

ax

Recovery Comparison

G

O

W

optimal location ⇨ 600 m SW


peripheral

original

crestal

27

0

1

0 500 1000 1500 2000Length (m)

Recovery Comparison

RF /

RF m

ax

G

O

W

Scenario 2 – Well A Length Sensitivities

Years

10

6 S

tb

0 20

3Cumulative Oil Production

Length ⇨ 200 ÷ 2000 m

optimal length range ⇨ 1200 – 1600 m

oil recovery ⇨ 2,3 – 2,5 x 106 Stb

1400 m

1200 m

1600 m

28

Scenario 2 – Well A Oil Rate Sensitivities

Rate ⇨ 500 ÷ 4000 Stb/d

Length ⇨ 1200, 1400 & 1600 m

1

2

3

0 1000 2000 3000 4000

10

6 S

tb

Rate (Stb/d)

Total Oil Recovery

1600 m

1200 m

1400 m

0

0.2

0.4

0.6

0.8

1

0 1000 2000 3000 4000

Total Oil Recovery / Time

10

3 S

tb

Rate (Stb/d)

0

0.8

1.6

2.4

0 1000 2000 3000 4000

10

9 S

tb

Rate (Stb/d)

(Total Oil Recovery)2 / Time

highest recovery

slow recovery less performing

29

Scenario 2 – Well B

depth ⇨ 8365 ft


length ⇨ 800 m

oil rate ⇨ 1500 ÷ 2000 (Stb/d)


Same workflow was applied to well B ⇨ orthogonal direction

30

Scenario 2 – Well C

depth ⇨ 8365 ft


length ⇨ 2000 m

oil rate ⇨ 1500 ÷ 2000 (Stb/d)


Same workflow was applied to well C ⇨ diagonal direction

31

1

2

3

0 1000 2000 3000

10

6 S

tb

Oil Rim Recovery

Length (m)

Scenario 2 – Direction & Length Comparison

Well C

Well B

Well A

Well A

Well C

Well B

Max Technical Length

• 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

32

List of Content


Project Scope


Wells Definition


Scenario 1

Scenario 2

Conclusions

33

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

34

Acknowledgements

I would thank Eni E&P Division Management for

permission to present this work and related results

and MOGI colleagues for the technical support and

needed assistance


6_mogi_gilio_presentation stage 2009 thin oil rim development

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