Fundamental studies for microbial enhanced oil recovery field test

This paper describes a series of experiments relevant to the screening of m icrobes to adapt and monitor the targeted microbes in the microbial enhance d oil recovery (MEOR) process. Firstly, the samples of reservoir brine, soi l of well site, drilling cuttings, and activated sludge were collected From domestic oil fields, drilling sites, sewage treatment facilities, and envi ronmental conditions. To achieve higher oil recovery, metabolic products of isolates were individually evaluated. These isolates were also incubated i n culture bottles packed with silica sands, to clarify the growth potential and metabolic activity in thr micro culture space. By carrying out two sta ges of flooding experiments simulating the reservoir environment, the capab ility of isolates for improving oil recovery was evaluated, and the microbe s were selected. Two gene-engineering techniques were established in parallel with the scree ning experiments for monitoring the microbes injected into the reservoir. T hese techniques are potentially capable of rapidly detecting the presence o f injecting microbes; moreover, they are available and effective for studyi ng the microbes relevant to the MEOR process. In addition, it was demonstra ted that metabolic activity of the microbes capable of producing effective gas could be estimated based on the quantity of 2,3-butanediol found as a m ajor end product of fermentation. The results of the huff & puff field test implied that the gene-engineering techniques established in this study and the metabolic activity analysis on 2,3-butanediol were effective for under standing the growth and metabolic activity of the microbes injected into th e reservoir.