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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