Indian IOR / EOR Experience Indian IOR / EOR Experience Case Studies Case Studies • Mumbai High IOR –Rolling Plan • Balol ISC- Heavy Oil EOR M M Dwivedi , GM (R), IRS
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Jan 30, 2016
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Indian IOR / EOR Experience Indian IOR / EOR Experience Case StudiesCase Studies
• Mumbai High IOR –Rolling Plan • Balol ISC- Heavy Oil EOR
M M Dwivedi , GM (R), IRS
Mumbai High IOR Rolling Plan
About the Field• Year of Discovery: 1974
• Type of Field: Offshore Multilayered
• Water Depth: 80 meters
• Location: About 165 km west ofMumbai, in offshore
• Area: About 1800 Sq. Km
• Structure: Anticline; eastern boundary fault; 1-2ºdip.(Graben in between N & S )
• IOIP: 1659 MMt approx.
• Gas cap: Large, covering about 50% area
Age Formation Units
L-I
L-II
S-I
L-IIIBombay
Post to Mid
Miocene
Mid. Miocene
Mid to Early
Miocene
Chinchini
Bandra
Tapti
Mahim
General Geology• Multi layered carbonate-sand-shale
complex of middle Miocene
• 70 km Long 25 km wide with a vertical closure of 375 m
• Commercially Exploitable zones are – L-II , L-III Limestone Oil & Gas– S1 Sand / Silt St. Gas
• L-III contains over 80% HC volume of the field
• For more than 35 years production has come from this pay .
Major Reservoir: L-III
• Divided into several layers – From ‘A’ to ‘J’ with intervening Shales
• Layer ‘A’ is the thickest and the main producer
• Layer ‘A’ is divided into A1 & A2
• Layer ‘A2’ is further subdivided into seven layers – A2-I to A2-VII
• Around 65 m thick
1350-
A1
A2-I
A2-III
A2-II
A2-IVA2-V
A2-VI
A2-VII
B
C
D
E
GR RLLD
MHN / MHS In-place Ultimate Cum Prod Reserves
Oil, MMt ~ 1500 ~ 560 ~ 376 ~ 184
Gas, BCM ~ 390 ~ 173 ~ 128 ~ 44
Basic Parameters
GOC (m) 1315/1330Deepest Free Water level (m) 1408/1460Reservoir thickness (m) 60 -100Porosity (%) 18-30Permeability (md) 50 -500Initial Oil Saturation 40 -70
Oil FVF 1.39
Gas FVF 0.008
˚ API 40
Initial Res Pressure (kg/cm2) 157Reservoir temperature ˚C 116
Stages of ExploitationPerformance of Mumbai High
0
50000
100000
150000
200000
250000
300000
350000
400000
450000
500000
1974 1977 1980 1983 1986 1989 1992 1995 1998 2001 2004 2007 2010 2013 2016 2019
Time
Oil
Rat
e, b
opd
Phase-IIPhase-IBase
IOR Phase-I
Initial Development
IORPhase-II
Water Inj.
Gas LiftInfill Drilling
• Continuous decline in Oil rate and increase in Water-cut in spite of drilling inputs
• CVC was 50% and Water injection rate was steeplydeclining
Mumbai High (L-III) :: Production Performance
0
60000
120000
180000
240000
300000
360000
420000
480000
540000
600000
Apr-76 Apr-80 Apr-84 Apr-88 Apr-92 Apr-96 Apr-00
Time
Oil/
Liq
uid
Rat
e, b
pd
0
40
80
120
160
200
240
280
320
360
400
Str o
n Pr
od
Liq RateOil RateStr on Prod
Mumbai High (L-III) :: Injection Performance
0100000200000300000400000500000600000700000800000900000
10000001100000
Apr-76 Apr-80 Apr-84 Apr-88 Apr-92 Apr-96 Apr-00
Time
WI R
ate,
bw
pd
010020030040050060070080090010001100
Cum
WI/
Cum
Voi
dage
, M
Mm
3
Cum VoidCum WIWI Rate
Concerns Felt (1998-2000)…
Concerns Felt (1998-2000)
• Deviation in Recovery Vs water-cut
• Pressure sink areas
Mumbai High : Watercut vs Recovery
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0 10 20 30 40 50 60 70 80 90 100
Recovery, %
Wat
ercu
t,%
• Afresh Geo-Cellular Model was prepared by Integrating Log Processed Data, 3-D Seismic Data and Geological information (capturing Heterogeneity)
• Reservoir Simulation Carried out on Fine Scale Model using ECLIPSE Software
• Installation of 14 Additional Platforms, Drilling of about 200 infill locations were envisaged under the Plan
• The recovery envisaged to be of the order of 32% by March 2030 ( 27% Base case)
• Approach to implementation: (2000-2007) • Dynamic planning –flexibility, focused attention • Learn-use-learn
IOR Phase-I : Implementation
• Field response to new technology & approach brought modifications in the plan
• Good success in accessing by-passed oil with increased productivity
• Success in Technology
– Horizontal & Multi-lateral – Use of LWD for Landing & Placement of Drain-hole– Use of Glycol & Synthetic Oil based mud system– Drilling of SRDH & MRDH to rehabilitate poorly
performing wells
IOR Phase-I Experience
IOR Phase-I Benefits Accrued• Acreage per well
reduced from 825 to 500
• Build up of Oil Prod
• Decline rate arrested
• Water-cut stabilized
• Imbibed New Technology in Drilling & completion
• MDT work culture developed for IOR management.
Mumbai High (L-III) :: Production Performance
0
50000
100000
150000
200000
250000
300000
350000
400000
450000
500000
0 50 100 150 200 250 300 350 400 450 500
Cum Oil, MMm3
Oil
Rat
e, b
pd
Mumbai High : Watercut vs Recovery
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
1.00
0 10 20 30 40 50 60 70 80 90 100
Rec,%
WC,%
• Significant Oil Gained
• Phase-I has been a significant learning curve to continue with the similar philosophy for IOR phase-II
Contribution of IOR Wells
0
1
2
3
4
5
6
7
8
2000-01 2002-03 2004-05 2006-07
Time
Year
ly O
il, M
Mm
3
0
5
10
15
20
25
30
35
40
Cum
Oil,
MM
m3
New WellsSidetracksCum. Oil
IOR Phase-I Evaluation
• Further improvement in Recovery Factor (~ 34%)• Further reduction in inter-well spacing (385 acres per
well)• Improvement in voidage compensation through water
injection ~ VRR 100 %.• Higher withdrawals through Submersible Pumps in
High Productivity wells• Development of Crestal area below GOC• Integration of L-I & L-II development with L-III• Drilling cost optimization, modular rigs
IOR Phase-II Aims
• Installation of 10 Additional Platforms, Drilling of about 160 Locations
• Installation of Submersible Pumps on ~100 wells• Enhanced Water Injection through ~65 additional
injectors • The recovery envisaged to be of the order of 34% by
March 2030• Under implementation. Completion schedule 2013
IOR Phase-II Inputs Envisaged
IOR Projects And Expected Recovery Improvements
0
5
10
15
20
2580
-81
83-8
4
86-8
7
89-9
0
92-9
3
95-9
6
98-9
9
01-0
2
04-0
5
07-0
8
10-1
1
13-1
4
16-1
7
19-2
0
22-2
3
25-2
6
28-2
9
Oil
MM
t
Actual Base Case Phase-I Phase-II Current Actual
27%
32 %34%
• Redistribution of water injection• Intelligent and segmented completion (gas, water
control)• High reservoir contact wells (Multilaterals)• Ultra short radius drilling towards exploitation of
Tighter layers sandwiched between flooded layers (about 26% in-place is locked in)
• Produced water handling (~500000 bwpd)• Improvements in sub-surface modeling using
information from horizontal wells
o Learning curve of Phase-II will guide the future plan
Way Forward: Beyond 2013
Balol ISCHeavy Oil EOR
19
Balol Field Parameters••Discovered in Discovered in :1970:1970••Put on production : 1985 Put on production : 1985 ••Viscosity : 50 Viscosity : 50 -- 1000 cp1000 cp•• API : 15 deg APIAPI : 15 deg API••Low Primary Rec. ~ 13 %Low Primary Rec. ~ 13 %•• Dip : 3Dip : 3--5 deg5 deg••13 km length & 1 km wide13 km length & 1 km wide
Location of Balol field
Thermal EOR processes
• Primary recovery very low (13%)• This necessitated Thermal EOR • Steam process was constrained due to
depth ,small pay thickness, strong water drive
• ISC process was therefore preferred
Oil bearing sands & Top-bottom shalesTarapur ShaleUpper Suraj Pay (U)
Kalol Sand-I (K-I)
Kalol Sand -II (K-II)Lower PayCambay Shale
17.42 MMt
0.10 MMt
3.56 MMt0.97 MMt
OIIP
KS-IKS-II
USP
B#167 B#153 B#163 B#159
KS-II
KS-I
USP
KS-I
USP
KS-IKS-II
USP
B#167 B#153 B#163 B#159
KS-II
KS-I
USP
KS-I
USP
E-W Cross Section
Reservoir & Fluid Propertieso Depth : 1000 mo Res Pressure : Hydrostatico Res Temperature : 70 deg Co Porosity : 25-30%o Permeability : 8 Darcieso Formation : Unconsolidated Sando Drive : Active watero Avg Oil Sat. : 77 %o GOR : 20 – 26 v/vo FVF : 1.05
Pilot Area
Regular Pattern
Pilot Area
Regular Pattern
Phase-I
Phase-II
Air Injectors
Phase-I
Phase-II
Phase-I
Phase-II
Air Injectors
N
Not to scale
Phase-I
Phase-II
Air Injectors
Phase-I
Phase-II
Phase-I
Phase-II
Air Injectors
N
Not to scale
Transition from Laboratory to Field
Prior to commercialization, process successfully tested in
• Laboratory • Field Pilot Stage• Semi-Commercial
Stage
Semi-Commercial
PilotAIR INJECTION WELL BALOL-21
B-85
Dominance of Gravity Segregation (Pilot observation well)
80 120 160 200 240
Dep
th, m 1050
1054
1058
1062
1046Sh
ale
Sand
Water Swept Zone
Shale
Siderite
Temperature, Deg C80 120 160 200 240
Dep
th, m 1050
1054
1058
1062
1046Sh
ale
Sand
Water Swept Zone
Shale
Siderite
Temperature, Deg C
Temperature at different time intervals
80 120 160 200 240
Dep
th, m 1050
1054
1058
1062
1046Sh
ale
Sand
Water Swept Zone
Shale
Siderite
Temperature, Deg C80 120 160 200 240
Dep
th, m 1050
1054
1058
1062
1046Sh
ale
Sand
Water Swept Zone
Shale
Siderite
Temperature, Deg C
Temperature at different time intervals
Advantages of Up-dip Line drive• Easy to control the process• Nullifies heterogeneity to a large extent• Less flue gas handling as part of flue gas will remain as
gas cap • Mitigate re-saturation of swept zone during unplanned
stoppage of air injection• Each producer will be traversed by the high temperature
front only once in the life of the project.• Air injection can be switched over to an adjoining hot
producer, thereby avoiding the necessity of artificial ignition.
Commercialization of ISC process
• Phase - I: Initiated in October 1997
• Phase – II: Initiated in May 2000
Envisaged Ignition of 30 wells in the first row
Ignition
• Artificial ignition ( Gas Burner)• Process initiation at HTO mode
• Enables high vertical sweep • Low Chances of oil saturation near the well bore
• Spontaneous Combustion tested in the field and carried out wherever required
Stabilized Produced Gas Composition
0
20
40
60
80
100
0
5
10
15
20
25
CO
2, O
2%
N2
, %
0
20
40
60
80
100
0
5
10
15
20
25
CO
2, O
2%
N2
, %
N2
CO2
O2 CO:ppm0
20
40
60
80
100
0
5
10
15
20
25
CO
2, O
2%
N2
, %
0
20
40
60
80
100
0
5
10
15
20
25
CO
2, O
2%
N2
, %
N2
CO2
O2 CO:ppm
Field : Air Rate Vs Oil Production rate
0
100
200
300
400
500
600
700
800
Tota
l Oil
Rat
e, m
3 /d
Air Injection Rate, MM Sm3/d
0.1 0.2 0.3 0.4 0.5 0.6 0.70
100
200
300
400
500
600
700
800
Tota
l Oil
Rat
e, m
3 /d
Air Injection Rate, MM Sm3/d
0.1 0.2 0.3 0.4 0.5 0.6 0.70
100
200
300
400
500
600
700
800
Tota
l Oil
Rat
e, m
3 /d
Air Injection Rate, MM Sm3/d
0.1 0.2 0.3 0.4 0.5 0.6 0.70
100
200
300
400
500
600
700
800
Tota
l Oil
Rat
e, m
3 /d
Air Injection Rate, MM Sm3/d
0.1 0.2 0.3 0.4 0.5 0.6 0.70
100
200
300
400
500
600
700
800
Tota
l Oil
Rat
e, m
3 /d
Air Injection Rate, MM Sm3/d
0.1 0.2 0.3 0.4 0.5 0.6 0.70
100
200
300
400
500
600
700
800
Tota
l Oil
Rat
e, m
3 /d
Air Injection Rate, MM Sm3/d
0.1 0.2 0.3 0.4 0.5 0.6 0.7
Field : Cum Air Injection vs Cum EOR oil
00.10.20.30.40.50.60.70.80.9
11.11.21.31.4
0 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700
Cum Air Inj, MMSm3
Cum
EO
R O
il, M
Mt
Envisaged Cum Oil, MMt
Actual Cum Oil, MMt
Injected and Produced Fluid Volumes (Reservoir Condition)
1997 98 99 2000 01 02 03 04 05 06 07 08 090
1500
3000
4500
6000
7500
0
20
40
60
80
100
Flui
d Pr
oduc
ed (R
es),
m3/
d
Flui
d_In
ject
ed (R
es),
m3p
d
WC
_per
cent
Saturation Reduction in Substitute Injector
Field : Performance
EOR Oil
AnxietiesAir Compressors• Explosions in compressed air piping due to
accumulation of carryover lubricants • Choking of cooling water lines due to scaling. • Appropriate synthetic lubricant was introduced
having higher auto ignition temperature • Reverse osmosis plant was set up to remove the
possibility of scale deposition• Regular chemical cleaning of the lines intensified
to mitigate the problem.
AnxietiesWell Completion• Well completion of old wells used as air injectors • Annular leaks of two air injectors resulted in
stoppage of air injection in entire field. • All old air injectors have been abandoned. • New substitute air injectors are being drilled. • New casing policy and right metallurgy for tubing,
casing and packer is adopted in all new air injectors to ensure rust free environment in the annulus.
Our Experience• ISC is an effective method for recovering oil from
heavy oil/bitumen reservoirs. (More than 40% RF)• Compression and injection of air into hydrocarbon
reservoirs is proven, but specialized technology.• Successful ISC requires robust engineering based on an
informed understanding of the process.• High temperature ignition, monitoring, and optimum air
injection rates are important.• Opportunity exists in terms of increasing oil production,
adding reserves and making money, provided ISC is operated in high temperature mode.
Thanks for Kind Attention
The journey needs to continue