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针对聚驱后油藏如何进一步提高石油采收率,在大庆油田萨南开发区的聚驱后区块开展了两轮激活内源微生物驱油现场试验研究,两轮激活体系总用量15611m~3,保护剂总用量5808m~3,总段塞体积为0.0785PV。试验结果表明,激活体系能够定向激活聚驱后油藏中的微生物;激活后的内源微生物产生大量的生物气,其中CO_2和CH_4含量变化存在交替增减,CO_2和CH_4的δ~(13)C(PDB)碳同位素含量变化范围在-54.5‰~-45.2‰和6.4‰~13.3‰之间波动;在两轮激活内源微生物驱油过程中,试验区注入压力升幅均在1.5MPa以上,其中第二轮保持在13~14MPa很长一段时间,为提高产量、延长增产期提供了有利条件。试验期间阶段累计产油20524t,扣除后续水驱自然递减及停产影响以外,阶段累计增油6243t,提高采收率3.93%。该技术的成功应用,为聚驱后油藏进一步提高采收率提供了一条有效途径。
In order to further improve the oil recovery rate after the polymer flooding reservoir, carried out two rounds of field experiments on endogenous microbial flooding in the poly-flooding block in the Sanan Development Zone, Daqing Oilfield. The total amount of two-round activation system is 15611m ~ 3 , The total amount of protective agent 5808m ~ 3, the total slug volume of 0.0785PV. The results showed that the activation system could activate the microorganisms in the reservoir after polymer flooding directionally. The activated endogenous microorganisms produced a large amount of biogas. The content of CO_2 and CH_4 changed alternately, the δ_ (13) of CO_2 and CH_4 increased, The variation range of C (PDB) carbon isotope fluctuated between -54.5 ‰ and -45.2 ‰ and 6.4 ‰ -13.3 ‰. During the two-step activation of endogenous microbial flooding, the injection pressure in the experimental area increased by more than 1.5 MPa, Among them, the second round maintained at 13 ~ 14MPa for a long time, which provided favorable conditions for increasing yield and prolonging the yield period. During the test period, oil accumulative total is 20524t, excluding the effect of subsequent waterflooding natural decline and production stoppage, the accumulative oil increment in the stage is 6243t, and the oil recovery rate is increased by 3.93%. The successful application of this technology provides an effective way for oil recovery after oil recovery.