A Study on Heterogeneous Composite Flooding Technology at the Zhenbei Oilfield

Following polymer flooding at the Zhenbei Oilfield, issues such as the scattered distribution of residual oil, increased reservoir heterogeneity, and deteriorating production performance under high water cut conditions have arisen. To address these issues, this paper employs a heterogeneous composite oil displacement system comprising microspheres, surfactants, and viscoelastic self-regulating agents. Through fundamental performance evaluations and core displacement experiments, parameters such as injection concentration, timing, volume, and slug formation were optimized to enhance oil displacement efficiency and improve reservoir mobilization. The optimal total injection volume for the heterogeneous system was determined to be 0.3 PV, with an optimal injection concentration of 0.3 wt %. The system was injected using a three-stage slug combination comprising 0.1 PV of microspheres, 0.1 PV of surfactant, and 0.1 PV of viscoelastic self-regulating agent. The ultimate recovery rate was increased by 27.41% compared with conventional water flooding. Based on these research findings, field pilot tests were conducted at the Zhenbei Oilfield. Daily oil production per well increased from 0.9 to 1.3 t, while the water cut decreased from 68.6 to 56.7%, achieving significant water control and oil production enhancement. This validated the system's excellent practical value for field application.