乳液微球颗粒调堵剂与岩心微观孔隙结构匹配关系研究

Research on matching relationship between emulsion microsphere particle plugging agent and micro-pore structure in cores

针对水驱油层低效、无效循环日趋严重的问题,开展了乳液微球颗粒调堵剂与岩心微观孔隙结构匹配关系研究。选取大庆油田喇嘛甸水驱区块取心井SⅡ油层组天然岩心为研究对象,将乳液微球颗粒调堵剂注入到岩心中进行溶胀封堵,再利用扫描电镜(SEM)及常规压汞仪观察该岩心强水洗后微观孔隙结构特征的变化。结果表明,随着注入乳液微球颗粒调堵剂的质量浓度由3000mg/L增大到9000mg/L,水驱后岩心孔隙半径由24~63μm变为10~25μm,孔隙度由29.7%降低至24.8%;最终提出乳液微球颗粒调堵剂与孔隙结构存在三种匹配关系,即未封堵、堵塞—运移—封堵、封堵。该研究为大庆油田水驱油层低效、无效循环后续水驱开发提供了技术支持。

In order to solve the growing problems of low efficiency and ineffective circulation in water-flooding reservoir,the matching relationship between emulsion microsphere particle plugging agent and micro-pore structure of core was studied.Taken the natural core of SII pay zone in Lamadian flooding block of Daqing Oilfield as a research object,the emulsion microsphere particle plugging agent was injected into the core to plug the payzones by swelling action,and then the change of micro-pore structure of the core after strong flooding was observed by means of scanning electron microscope(SEM)and conventional mercury pressure gauges.The results showed that the pore radius of the core decreased from the range(24~63μm)to(10~25μm)and the porosity decreased from 29.7%to 24.8%after water flooding with the increase of mass concentration of the injected emulsion microsphere particle plugging agent from 3000 mg/L to 9000 mg/L.Finally,it is proposed that there are three matching relationships between the emulsion microsphere particle plugging agent and pore structure in cores,i.e.unplugged,blocked-migrate-plugged,and plugged.The study provides the technical support for the follow-up development of oil reservoirs with low efficiency and ineffective circulation by water flooding in Daqing Oilfield.