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

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

Heavy Oil Fields In Place : 144 MMt Viscosity : 50 - 1500 cP API : 13 – 17 Low Prim. Rec. : 5-15 % Depth : 1000 m Drive Mechanism : Active edge water 3

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

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.

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

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

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(1990) Steam Flood Pattern (not implemented) Phase-I Phase-II Due to encouraging results of ISC pilot Steamflood Pilot withdrawn

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

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

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

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

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

ISC in Santhal Field Recovery : 27 % OIIP Updip line drive strategy (As on 01.12.2011) Updip line drive strategy Pay Sands : USP,KS-I, II,III, LRP EOR (ISC) Phase-I : Apr’1997 Main : Sep’2000 Viscosity (cp) : 60-150 LEGEND KS-I Commingle Production KS-I Exclusive Gassed Out wells KS-I Air Injectors Other Air Injectors Recovery : 27 % OIIP

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

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

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

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

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

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 10-15 days Followed by a soak period Well is put back on production

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.

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

Thank You

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

Rock and Fluid Characteristics Depth : 1000 m Thickness : 5-25 m Permeability : 1-5 Darcies Viscosity : 50-1500 cP Drive Mechanism : Active edge water