一种低渗油藏深部调驱用聚合物纳米微球的制备与性能研究

Study on preparation and performance of polymer nanospheres for deep profile control and flooding in low permeability reservoir

储层非均质性严重、裂缝孔道分布复杂与近井地带剩余油饱和度下降等现象严重制约了常规调驱技术在低渗油藏的应用。采用分散聚合法制备了纳米聚合物微球,表征了微球吸水与干燥时的微观形貌,研究了微球的吸水膨胀性能与调驱机理。结果表明,微球形状规则、球形度高,分散在模拟地层水中最低达145 nm。模拟油藏环境下,微球吸水浸泡102 h,体积膨胀可达30倍,表现出较好的抗温耐盐与吸水膨胀能力。设计微观驱油实验,微球在孔道中表现出“运移—封堵—突破—再封堵”的调驱过程,显著提升了波及体积,体现出良好的选择封堵性能,适用于低渗油藏深部调驱。

Reservoir heterogeneity,complex distribution of fracture pores,and decrease of remaining oil saturation in the near-wellbore zone have severely restricted the application of conventional profile control and displacement technology in low-permeability reservoirs.Nano-polymer microspheres were prepared by dispersion polymerization,and the microscopic morphology of the microspheres when they absorbed water and dried.The water-absorbing swelling performance and the control and displacement mechanism of the microspheres are also studied.The results show that the microspheres have regular shapes and high sphericity,and they are dispersed in the simulated formation water as low as 145 nm.In a simulated oil reservoir environment,the microspheres can be immersed in water for 102 h,and their volume expansion can reach 30 times,showing good resistance to temperature and salt and water swelling ability.Designing micro-displacement experiments,the microspheres showed a“migration-plugging-breakthrough-re-plugging”control and flooding process in the pores,which significantly increased the swept volume and showed good selective plugging performance,suitable for low permeability deep profile control and flooding in the reservoir.