CONING CONTROL AND RECOVERY IMPROVEMENT IN BOTTOM WATER DRIVE RESERVOIR VIA DOWNHOLE WATER SINK AND DOWNHOLE WATER LOOP

MOHD RUZAINI BIN RUSLIA11KP0030

PRESENTATION OUTLINE• INTRODUCTION• OBJECTIVE OF STUDY• RESULT AND DISCUSSION• CONCLUSION

INTRODUCTION

WATER CONING-The change in the oil-water contact profile as a result of drawdown pressures during production.

DOWNHOLE WATER SINK-Downhole water sink (DWS) is a technique for minimizing water cut in wells producing hydrocarbons from reservoirs with bottom water drives and strong tendencies to water coning.

DOWNHOLE WATER LOOPA natural extension of the water sink technology for small aquifers is the concepts of returning the drained water to the same aquifer using triple-completed wells with downhole water loop (DWL) technology .

OBJECTIVE OF STUDY• To examine the potential of DWL for improving oil recovery

factor and produced water reduction.

• To compare the recovery performance of conventional, DWS and DWL wells in the reservoir with bottom water coning.

• To determine which method is the most efficient in controlling the water coning with most high value of oil recovery factor and less in economical factor.

METHODOLGYRESERVOIR MODEL

• A black-oil commercial simulator (IMEX) by CMG was used.

• The ‘layer cake’2D reservoir model was used in this study.

• No flow outer boundary condition.

Oil Zone Grid• 20X55

Water Zone Grid• 60X55

PARAMETERS INVOLVED

1. Type of completion• Single completion for conventional• Dual completion for DWS• Triple completion for DWL

2. Effect of initial reservoir pressure• Initial pressure gradient; 0.40, 0.45 and 0.5 psi/ft

3. Effect of penetration interval• Length of perforation; 10, 20 and 30 ft

RESULT AND DISCUSSIONBASE CASE

DATA UNIT VALUESDatum depth ft 9265Thickness of oil zone ft 40

Thickness of water zone ft 120Initial reservoir pressure psia 3706

Position of water drainage completion from WOC ft 10

Horizontal permeability md 35Vertical permeability md 38.5

Porosity fraction 0.164Well radius ft 0.292

Outer radius of oil zone ft 1000Capillary pressure Ignored

MODEL OIL PRODUCTION (bbl)Conventional 1 755 486

DWS 2 481 541DWL 1 801 892

0 10000 20000 30000 40000 50000 60000 70000 800000

500000

1000000

1500000

2000000

2500000

3000000

Cumulative Oil Production

DWL ModelDWS ModelConventional

Time (day)

Cum

ulati

ve O

il (M

bbl

)

0 10000 20000 30000 40000 50000 60000 70000 800000

2000000

4000000

6000000

8000000

10000000

12000000

14000000

16000000

18000000

Cumulative Water Production

DWL ModelDWS ModelConventional

Time (day)

Cum

ulati

ve W

ater

(M b

bl)

MODEL WATER PRODUCTION (bbl)

Conventional 16 140 046

DWS 15 364 982

DWL 16 068 897

0.001 0.01 0.1 1 10 100 1000 10000 1000000

10

20

30

40

50

60

70

80

90

100

Water Cut

DWL ModelDWS ModelConventional

Time (day)

Wat

er C

ut (%

)

MODEL WATER CUT (%)

Conventional 93.86

DWS 92.74

DWL 93.79

EFFECT OF INITIAL RESERVOIR PRESSURE

0 20000 40000 60000 800000

500000

1000000

1500000

2000000

2500000

3000000

Cumulative Oil with Pi = 4170psia

DWL ModelDWS Model

Time (day)

Cum

ulati

ve O

il (M

bbl)

Pi (psia) MODEL OIL PRODUCTION (Mbbl)

4170 DWS 2.51

DWL 1.82

4633 DWS 2.53

DWL 1.83

0 20000 40000 60000 800000

500000

1000000

1500000

2000000

2500000

3000000

Cumulative Oil with Pi = 4633 psia

DWL ModelDWS Model

Time (day)

Cum

ulati

ve O

il (M

bbl

)

0.0010.01 0.1 1 10

1001000

10000

1000000

102030405060708090

100

Water Cut for Pi = 4170 psia

DWL ModelDWS Model

Time (day)

Wat

er C

ut (%

)

Pi MODEL WATER CUT (%)

4170 DWS 92.7

DWL 93.8

4633 DWS 92.6

DWL 93.7

0.0010.01 0.1 1 10

1001000

10000

1000000

102030405060708090

100

Water Cut for Pi = 4633 psia

DWL ModelDWS Model

Time (day)

Wat

er C

ut (%

)

EFFECT OF PENETRATION INTERVALS

0 20000 40000 60000 800000

500000

1000000

1500000

2000000

2500000

3000000

Cumulative Oil for Perforation Length of 20 ft

DWL ModelDWS Model

Time (day)

Cum

ulati

ve O

il (M

bbl

)

LENGTH OF PERFORATION (ft)

MODEL OIL PRODUCTION (Mbbl)

20 DWS 2.48

DWL 1.81

30 DWS 2.49

DWL 1.82

0 20000 40000 60000 800000

500000

1000000

1500000

2000000

2500000

3000000

Cumulative Oil for Perforation Length of 30 ft

DWL ModelDWS Model

Time (day)

Cum

ulati

ve O

il (M

bbl

)

0.0010.01 0.1 1 10

1001000

10000

1000000

102030405060708090

100

Water Cut for Perforation Length of 30 ft

DWL ModelDWS Model

Time (day)

Wat

er C

ut (%

)LENGTH OF

PERFORATION (ft)MODEL WATER CUT (%)

20 DWS 92.8

DWL 93.8

30 92.8

93.8

0.0010.01 0.1 1 10

1001000

10000

1000000

102030405060708090

100

Water Cut for Perforation Length of 20 ft

DWL ModelDWS Model

Time (day)

Wat

er C

ut (%

)

CONCLUSION• In bottom water drive reservoir, the oil recovery was significantly limited by the aquifer

strength.

• The effect of initial reservoir pressure for both DWS and DWL models was nearly to nothing because it just had a little effect of the shape of oil water contact and water encroachment.

• Similar to the initial reservoir pressure, penetration interval or length of perforations also had a little effect on the oil recovery since it provided energy for the oil flowing to the production well.

• If there was a disposal zone existed in the reservoir, DWS was a better choice than DWL and conventional models because of its fast recovery process and low water cut in the produced fluids.

• DWL model was considered for a better choice because it produced less water to the surface by reinjected those water produced into the reservoir, thus controlled the water coning and prevented quick pressure depletion in reservoir.

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