Bacillus菌株提高碳酸盐油藏采收率的实验研究

EXPERIMENTAL STUDY ON BACILLUS STRAINS USED FOR IMPROVING OIL RECOVERY IN CARBONATE RESERVOIRS

微生物驱油技术(MEOR)近年来在世界多个油田取得了成功,大部分的实验室研究和现场应用都是针对砂岩油藏进行的,该技术在碳酸盐油藏中的研究很有限。两株Bacillus细菌在特定的温度下繁殖后,其代谢物被用于油水界面张力测试、玻璃模型驱油实验和碳酸盐岩心采收率实验。结果表明,细菌代谢物可大幅降低界面张力,并有效提高采收率。根据实验现象,微生物在碳酸盐岩石中的驱油机理是对高渗透率裂缝的选择性封堵。

Many successful field cases of microbial enhanced oil recovery(MEOR) method have been reported for sandstone reservoirs. The objective of this study is to investigate the potential of MEOR method in carbonate reservoirs. Two Bacillus strains were incubated at certain temperatures,and their effects on crude oil properties and recovery were tested. It was discovered that the strains could effectively reduce oil-water interfacial tension(IFT) . Bacteria solutions were subsequently injected into a glass Hele-Shaw model and limestone core. The bacteria flooding lead to improved oil recovery. The observation on core flooding tests indicated selective plugging as the dominant recovery mechanism.