July 2011EEOR Success in Mann Field, MyanmarWilliam K. Ott, P.E., SPE, Well Completion TechnologyThu Nyo, SPE, MPRL E&P Pte LtdWin Nyunt Aung, SPE, MPRL E&P Pte LtdAung Thet Khaing, SPE, MPRL E&P Pte Ltd
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EEOR, or enzyme-enhanced oil recovery, is an adaptation of MEOR (microbial-enhanced oil recovery), an EOR (enhanced oil recovery) technique. MEOR is an emerging technology that may help recover the 377 billion barrels of oil that are unrecoverable by conventional technologies (Sen, R. 2008).Enhanced oil recovery, also called improved oil recovery or tertiary recovery (as opposed to primary and secondary recovery),is achieved by gas injection, chemical injection, microbial injection, or thermal recovery (which includes cyclic steam, steam flooding, and fire flooding). Gas re injection is presently the most-commonly used approach to enhanced recovery. Application of all EOR processes alter the original properties of crude oil and are intended to increase the life of mature oil reservoirs.However, they can actually be initiated at any time during the productive life of an oil reservoir. Their purpose is not only to restore formation pressure but also improve oil displacement or fluid flow in the reservoir to unlock trapped oil (Figure 1).Enzymes, the broad class of protein-based catalysts found in all living matter, are what constitute EEOR. Enzyme are non living, which provides EEOR an advantage over MEOR techniques that may require a detailed pretreatment involving the injection of a fermentable carbohydrate nutrient base into the reservoir before the microorganisms. Use of naturally occurring microorganisms may also lead to undesired side effects, such as production of CO2, biomass, and surfactants; degradation of oil components; and reservoir souring. Additionally, reservoir conditions that restrict MEOR applications are high total salinity (12%), formation temperatures (above 122F), and very low permeability. These conditions do not restrict EEOR, which allow for a broader range of well treatment applications.Successful applications of EEOR have been documented in China, Indonesia, Venezuela, and elsewhere. This paper discusses EEOR trial applications in Mann Field, Myanmar of a specific modified enzyme.