Experiences of microbial enhanced oil recovery in Chinese oil fields

Microbial enhanced oil recovery (MEOR) is a unique technique but remains relatively marginal. However, trials of MEOR in Chinese oil fields are still active. This paper briefly discusses the mechanisms of MEOR, then reports more than twenty MEOR field projects carried out in China since 2000. Those field cases were not well known due to language barrier. The cases were implemented over months or even years. According to field experiences in China, MEOR achieved good success rates, with around 70% of treated wells showing positive responses. Besides, all of the projects were profitable. Traditionally, high temperature and high salinity have been obstacles for field applications of MEOR, but the field cases in China extended the method to more challenging reservoir conditions. MEOR has been tried in tight formations, high-salinity reservoirs, high-temperature reservoirs, and heavy-oil fields. MEOR proved effective for challenging reservoir conditions with careful selection of microbes and proper project execution.