二类油层聚驱微观驱油效率影响因素研究

Influencing Factors of Microscopic Oil Displacement Efficiency by Polymer Flooding in Class II Reservoirs

何源媛 钟会影 郭松林 杨庭宝

Yuanyuan He Huiying Zhong Songlin Guo Tingbao Yang

东北石油大学 石油工程学院，黑龙江 大庆 163318 中国石油大庆油田有限责任公司 勘探开发研究院，黑龙江 大庆 163712 中国石油大庆油田有限责任公司 第二采油厂，黑龙江 大庆 163458

School of Petroleum Engineering，Northeast Petroleum University，Daqing Heilongjiang 163318，China Research Institute of Exploration and Development，Daqing Oilfield Company，PetroChina，Daqing Heilongjiang 163712，China Second Oil Production Plant，Daqing Oilfield Company，PetroChina，Daqing Heilongjiang 163458，China

二类B油层目前已经成为大庆油田的主要开采对象，其地质储量占二类油层的45.8%。针对二类B油层开采差异较大的现象，建立了黏弹性聚合物?原油两相数学模型，并采用对数构象法进行变换；利用VOF法追踪聚驱过程中的两相界面，得到了黏弹性聚合物?原油两相流的数值模型；通过二类油层微观模型研究孔隙结构和聚合物黏弹性对微观驱油效率的影响。结果表明，储层非均质性越强，微观驱油效率越低，孔隙参数较好的二类A油层的驱油效率高于二类B油层2.10%；随着黏度的增加，微观驱油效率增大，黏度比（聚合物与原油的黏度比）为1.5 ∶ 1、2.0 ∶ 1和10.0 ∶ 1的方案驱油效率比黏度比为1.0 ∶ 1的方案高0.59%、0.80%和4.10%；随着弹性的增加，微观驱油效率增大，但当松弛时间大于13 s后，微观驱油效率略有降低，说明聚合物的弹性对驱油效率的贡献存在最优值。研究结果为大庆油田二类B油层聚驱开发提供了重要的理论支撑。

Class II?B reservoirs have become the main exploitation target in Daqing Oilfield, and their geological reserves account for 45.8% of the Class II reservoirs.In view of the huge difference in the exploitation of Class II?B reservoirs,a two?phase mathematical model of viscoelastic polymer solution and crude oil was built,and the logarithmic conformation method was used to transform the model.The VOF method was employed to track the two?phase interface in the displacement process,and thus a two?phase numerical model of viscoelastic polymer solution and crude oil was obtained.Moreover,the effects of pore structure and viscoelasticity of polymer on microscopic oil displacement efficiency were studied by the microscopic model of Class II reservoirs. The results demonstrate that higher reservoir heterogeneity is accompanied by lower microscopic oil displacement efficiency,and the oil displacement efficiency of Class II?A reservoirs with better pore parameters is 2.10% higher than that of Class II?B reservoirs.With the increase in viscosity,the microscopic oil displacement efficiency increases,and the oil displacement efficiency of schemes with a viscosity ratio of (viscosity ratio of polymer to crude oil) 1.5 ∶ 1,2.0 ∶ 1 and 10.0 ∶ 1 is 0.59%,0.80% and 4.10% higher,respectively, than that with a viscosity ratio of 1.0 ∶ 1. With the increase in elasticity, the microscopic oil displacement efficiency rises, but when the elasticity is higher than 13 s,the microscopic oil displacement efficiency decreases slightly,which indicates that the elasticity of polymer solution has an optimal value for improving oil displacement efficiency.The research results provide important theoretical support for the polymer flooding development of Class II?B reservoirs in Daqing oilfield.

中国博士后科学基金项目(2019M661250);黑龙江省博士后经费资助项目(LBH?Z19050)

10.12422/j.issn.1006-396X.2023.02.005