Microbial enhanced oil recovery in China: progress and prospects

As an economical and sustainable approach for the enhancement of oil recovery, microbial enhanced oil recovery has gained prominence in residual oil recovery from depleted oil reservoirs that are economically marginal or technically challenging due to low permeability, elevated water content and bearing heavy oil, particularly under current economic constraints in the petroleum industry. Over the last few decades, intensive efforts have been invested and extensive studies have been conducted regarding MEOR in both laboratory studies and field applications, with positive responses in oil reservoirs under different conditions. This study reviews recent advances in microbial enhanced oil recovery in oilfields in China, focusing on the latest knowledge regarding dominant microbial communities in oil reservoirs, microbes and their interactions in oil reservoirs and the key roles of microbial products in oil recovery. Strategies for microbial enhanced oil recovery and microbial enhanced energy recovery, including the novel concept of "Microbial plus" which refers to the microbial combined chemical method to enhance synergistic efficiency for enhanced oil recovery, are investigated. At last, recent field trials in Chinese oilfields were systematized based on the corresponding technologies utilized.