Prospects for thermophilic microorganisms in microbial enhanced oil recovery (MEOR).

摘要

Studies in this laboratory have shown that certain species of thermophilic microorganisms may satisfy microbial enhanced oil recovery (MEOR) requirements. Several species of thermophilic microorganisms have been grown in the presence of varying concentrations of crude oils at different temperatures and pressures. Experimental evidence indicates that some thermophiles are viable over long periods of time (six months) at 70(degree)C and 2000 psi in the presence of crude oils as the sole source of carbon. The interaction between selected thermophilic microorganisms occurs in some cases under aerobic and in others under anaerobic conditions. During the interactions there are pH changes due to production of acids. Crudes are also emulsified. The extent of emulsification is microbial-species dependent, and considerable variations have been observed when the same crude oil has been biotreated with different types of microorganisms under otherwise identical experimental conditions. The analysis of the emulsified fraction indicated that hydrocarbons in the C(sub 13)--C(sub 26) range were present in the emulsion. The biotreatment also caused changes in the composition of the organic sulfur fractions, as well as an overall decrease in the content of sulfur-containing compounds of the crude oils tested. Further, biotreatment caused significant qualitative and quantitative changes in low and high molecular weight fractions of test oils. The observed changes in different molecular weight fractions are also species dependent. Experimental data will be presented and their significance in terms of MEOR will be discussed. 22 refs., 14 figs., 3 tabs.