RIASSUNTO
India’s crude oil reserves tend to be light and sweet, with specific gravity varying from 38° API in the offshore Mumbai High field to 32° API at other onshore basins. India produced roughly 880 thousand barrels per day (bbl/d) of total oil in 2009 from over 3,600 operating oil wells. Enhanced oil recovery (EOR) is a term applied to methods used for recovering oil from a petroleum reservoir beyond that recoverable by primary and secondary methods. Primary recovery normally refers to the production using the energy inherent in the reservoir from gas under pressure or a natural water drive. Secondary recovery refers to usually refers to injection of water or water flooding thus, enhance oil recovery is often synonymous with tertiary recovery. Four group of methods -thermal recovery, gas miscible recovery, chemical flooding and microbial flooding are included in this collection.
Implemented EOR techniques in India include alkaline surfactant flooding (ASF) in Jhalora-Rajasthan, Kalol-Gujarat, and Ankleshwar-Gujarat, immiscible hydrocarbon water alternating gas injection (HC-WAG) in Gandhar fields- South Gujarat, in-situ combustion/air Injection and simultaneous water and gas injection (SWAG) in Mumbai High.
Some of the EOR pilots on anvil are immiscible CO2, microbial in-situ stimulation, and paraffin control microbes in western onshore regions of India. The planned techniques include air injection in light oil in western offshore, immiscible flue gas in western onshore and immiscible CO2 in eastern onshore.
The Indian government and other oil E&P organizations expects this geographical dependence to rise in light of limited prospects for domestic production and hence, interested in Enhanced oil recovery techniques. The complete paper would discuss case studies of some of the selected Indian oil fields mentioned above.