Volume 49

Study on Distribution Patterns of Displacement Pressure Gradients and Regulation Effectiveness of Chemical Flooding in Strong Heterogeneity Reservoir Yaqian Zhang, Chuanhui Miao, Shilin Zeng, Yiqiang Li, Jinxin Cao, Xuechen Tang, Zheyu Liu, Qihang Li, Tao Song

Abstract

Compared with onshore oil fields, offshore oil fields have lower well pattern completeness, larger well spacing, and stronger heterogeneity, necessitating a profile control and flooding system as well as corresponding laboratory evaluation methods to achieve deep reservoir regulation and efficient development. This study compared the performance of different chemical agents, simulated the heterogeneous development process of offshore oil reservoirs in both vertical and planar planes, and conducted multi-point pressure measurements. By analyzing the profile control and flooding effects under different reservoir conditions and the differences in pressure gradient distribution during the displacement process, the regulation mechanisms under different reservoir conditions were revealed. The results showed that during the development of vertically heterogeneous reservoirs, the pressure gradient difference along the high-permeability layer was less than 0.01 MPa/m, indicating a relatively uniform distribution. This indicates that the selected chemical system can achieve deep regulation of the high-permeability layer, increasing the recovery factor by 50.4%. During the development of planar heterogeneous reservoirs, the pressure gradient in the near-well zone was significantly greater than that in the far-well zone, resulting in an increase in the pressure at the core boundary. This indicates that the selected chemical system can achieve the development effect of subsequent fluid bypassing and further expansion of the swept area, increasing the recovery factor by 31.1%. This study provides theoretical guidance and technical support for field implementation.

Keywords strong heterogeneity, physical experiment, displacement pressure gradient, regulation effect