1. A review of In-Situ Combustion Operations in India, its Assessment and the Way ahead1 1

2. Presentation Outline Need of Thermal EOR Laboratory Investigations
Field Pilot testing of In-Situ Combustion (ISC) process
Commercial Exploitation
Lessons Learnt
Projects in Pipeline
Conclusions

3. Heavy Oil Fields In Place : 144 MMt Viscosity : 50 - 1500 cP
API : 13 – 17
Low Prim. Rec. : %
Depth : 1000 m
Drive Mechanism : Active edge
water 3

4. Light Oil, Medium Gravity Oil and Heavy Oil
Med. Grav. oil
Heavy oil

5. Need for Thermal EOR Poor Mobility of oil - Due to high viscosity
Low Recovery - Due to viscous fingering of water
To improve recovery, in-situ combustion process under application since 1990.

6. In-situ Combustion Process
02/12/2012
Cewell Symposium

7. Laboratory Investigations
Engineering parameters
Fuel deposition
Air requirement
Peak Temperature
Recovery
Produced Fluid properties
If the process is successful in laboratory, it may not be successful in field. But if it is a failure in laboratory, it is bound to be failure in field. 7

8. Balol Pilot & Semi Commercial Pattern
Pilot commissioning : March 1990
Inverted 5-spot 5.5 acre pattern
Semi-
Commercial (1992)
Pilot (1990)
Steam Flood
Pattern
(not implemented)
Phase-I
Phase-II
Due to encouraging results of ISC pilot Steamflood Pilot withdrawn

9. Pilot Outcome Combustion could be created, sustained and propagated
Process is gravity controlled
Incremental oil production of 8250 t at AOR of 1000 v/v
Bottom Hole Temperature Measurement in Observation well B#85 9

10. Commercial Exploitation by ISC
1997 : Phase-I area (Southern part)
2000 : Entire Balol field
RF : 43 % OIIP
Initial ISC plan - Pattern
Modified to - Updip line drive
Crestal line drive air injection preferred over pattern or downdip air injection

11. Commercial Exploitation by ISC
Updip line drive air injection
Incremental oil gain : 1.94 MMt
Phase-I
Current Recovery : 22 % Targeted OIIP

12. Performance of Balol Field
Max Qair : 6.75 lacs Nm3/d
Increase in Qo from 300 m3/d to 750 m3/d
AOR : 1000 v/v

13. Sectorwise Performance Performance Improvement Required North Block
OIIP : 5.10 MMt
Cum Oil : 0.29 MMt
Recovered : 6 % of OIIP
Sectorwise
Performance
North Block
Performance Improvement
Required
Block of BL#198
OIIP : 1.71 MMt
Cum Oil : 0.19 MMt
Recovered : 11 % of OIIP
Block BL#198
Block of BL#169
OIIP : 1.77 MMt
Cum Oil : 0.38 MMt
Recovered : 21 % of OIIP
Block
BL#169
Block
BL#139
Block of BL#139
OIIP : 0.84 MMt
Cum Oil : 0.08 MMt
Recovered : 9 % of OIIP
Block
BL#189
Block of BL#189
OIIP : 1.60 MMt
Cum Oil : 0.41 MMt
Recovered : 26 % of OIIP
Block
BL#179
Block of BL#179
OIIP : 2.02 MMt
Cum Oil : 0.59 MMt
Recovered : 29 % of OIIP
GGS-II Area
OIIP : 2.02 MMt
Cum Oil : 0.89 MMt
Recovered : 44 % of OIIP
GGS-II
Area
Phase-I
Phase-I Area
OIIP : 2.27 MMt
Cum Oil : 1.2 MMt
Recovered : 53 % of OIIP

14. ISC in Santhal Field Recovery : 27 % OIIP Updip line drive strategy
(As on )
Updip line drive strategy
Pay Sands : USP,KS-I, II,III, LRP
EOR (ISC) Phase-I : Apr’1997
Main : Sep’2000
Viscosity (cp) :
LEGEND
KS-I Commingle Production
KS-I Exclusive
Gassed Out wells
KS-I Air Injectors
Other Air Injectors
Recovery : 27 % OIIP

15. Upward trend in production due to EOR and IOR exploitation strategy
Performance of Santhal Field
Upward trend in production due to EOR and IOR exploitation strategy

16. Lessons Learnt
Air injection is an effective method for recovering heavy oil
Recovery more than 50% in moderately thick and viscous hy.oil reservoirs
High energy efficiency of the process with AOR of 1000 v/v
Av. hp : 6.5 m
Viscosity : 150 cP
Affected area

17. Lessons Learnt
In an active water drive reservoir, arresting edge water movement along with displacement of oil plays major role
Recovery > 53 % OIIP

18. Lessons Learnt Poor vertical sweep in thick and viscous oil reservoir
Recovered 6 % of OIIP at AOR of > 2000 v/v
hp 20 m
235 18

19. In Pipeline
Needs different approach for very thick and highly viscous reservoir
Planned to test Toe to Heel Air Injection (THAI) to improve the performance of ISC process

20. In Pipeline Planned to test Cyclic Steam Stimulation in few wells
Thereafter ISC in conjunction with a few cycles of CSS
Injection of Steam for days
Followed by a soak period
Well is put back on production

21. Impact of Low Oil Prices
There is a strong relationship between oil prices and new EOR projects.
EOR production increases when oil prices increase but when the prices fall EOR production declines but not to the extent predicted.

22. Impact of Low Oil Prices
3D Seismic to determine where the target oil is located in old as well as new fields
Reservoir characterisation
Extensive field testing of R & D projects
Side tracking of existing non-flowing wells
Use of horizontal wells with multilaterals, short radius, and those used in lieu of more costly infill drilling

23. Thank You

24. Lessons Learnt
Process demands rigorous monitoring of combustion parameters and mode of oxidation

25. Rock and Fluid Characteristics
Depth : 1000 m
Thickness : 5-25 m
Permeability : 1-5 Darcies
Viscosity : cP
Drive Mechanism : Active edge water