聚驱后油藏内源微生物激活体系评价研究

Evaluation of Indigenous Microorganism Activation System in the Reservoir after Polymer Flooding

针对聚驱后油藏如何进一步提高石油采收率的技术难题,开发了一种用于促进油藏内源微生物生长代谢的高效激活体系。室内通过物理模拟驱油试验、产气试验、岩心电镜观察试验对该激活体系激活聚驱后油藏内源微生物生长以提高采收率的有效性进行了评价,并将其应用于大庆油田萨南开发区的一个试验井组。结果表明,该激活体系能够激活聚驱油层注入污水中的内源微生物,使其在岩心中大量生长繁殖,原油采收率在聚合物驱后基础上可以再提高3%以上;产气试验中激活体系能够激活注入水中的内源微生物代谢产生大量的生物气,使密闭容器压力呈阶段性升高;现场注入激活体系后,聚合物驱后油藏中有明显的产气增压效果,实现阶段累计增油3068.1t,含水率下降2.2%,为化学驱后油藏进一步提高石油采收率提供了一条有效途径。

In allusion to the problem of further enhancing oil recovery in the reservoirs after polymer flooding,an efficient activating system for promoting metabolism of indigenous microorganism is developed.For evaluating whether indigenous microorganism activation system screened in laboratory can activate indigenous microorganisms for enhancing oil recovery in reservoirs after polymer flooding,physical simulation experiments,aerogenic experiments and electron microscopy scanning(SEM)experiments are conducted and this activation system is used for testing well groups in Sa'nan Development Zone of Daqing Oilfield.The results show that the activation system canactivate the indigenous microorganisms in the injected sewage and make them grow and reproduce a lot in the core and enhance oil recovery by3% after polymer flooding.In the aerogenic experiments,the activation system can activate the indigenous microorganisms in the injected water and produce a lot of biogas and raise the pressure in the closed vessel at the stage.In the field test,there exists a significant gas supercharging effect and the accumulated oil increment is 3068.13 twith water content declination of 2.2%,which provides an effective way to further enhance oil recovery in the reservoirs after chemical flooding.