海上油田微生物驱油体系的建立及效果评价

Establishment of Microbial Oil Displacement System for Offshore Oilfield and Its Effect Evaluation

针对渤海某稠油油藏地层条件及基础菌群特征,筛选有效激活剂,激活地层中有益微生物菌群,并筛选功能菌群进行地面发酵后回注,以弥补无空气注入导致的近井地带好氧区微生物代谢活动的不足。由于海上油田注采强度大,为了避免营养药剂随注入水过早采出,影响微生物繁殖,创新性地建立了营养凝胶体系,以增大营养组分滞留时间,从而激活油藏深部微生物。通过室内岩心驱替试验优化了营养凝胶和微生物驱剂的段塞大小,二者共同作用下可提高采收率18.4%,目标试验区微生物驱油应用潜力较高。

Aiming at geologic condition and basic bacteria group characteristics of a heavy oil reservoir in Bohai Oilfield an effective activator was chosen it activate the beneficial microbial bacteria group in the strata,after functional bacteria were chosen for surface fermentation,they were re-injected in to formation to make up for the near wellbore zone of no air injection in aerobic zone of microbial metabolic activity.For high injection-production strength in offshore oilfields, to prevent earlier production of nutrition agent with injected water and affecting the microbial breeding,nutrition gel system was established innovatively to increase the residence time of nutrition component to activate the deep reservoir microbes.Nutrient gel is optimized by laboratory core displacement experiment and microbial flooding agent slug size is optimized,oil recovery can be improved by 18.4% by using the combination of both,in the target experimental zone, microbial flooding has high potential of application.