Injection evaluation method for the horizontal well in heterogeneity reservoir considering wellbore friction

Author of the article:ZHANG Hongyou, WANG Meinan, WU Chunxin, LIU Wenzheng, ZHANG Yanhui

Author's Workplace：Bohai Oilfield Research Institute of CNOOC Ltd., Tianjin, Branch Tianjin, 300452, China

Key Words：Horizontal water injection well; Wellbore friction; Reservoir heterogeneity; Principle of superposition; Injection capacity evaluation

Abstract：In the complex fault-block fluvial facies oilfield in the south of the Bohai Sea, the uneven distribution of injection volume along the horizontal water injection wells has seriously affected the water injection development effect. Based on the principle of potential superposition and mirror reflection, this paper established an evaluation method of water injection capacity of horizontal water injection wells, considering the effects of reservoir heterogeneity and wellbore for the injection-production well pattern of horizontal wells. The evaluation results show that: influenced by wellbore, the injection rate along the horizontal section decreases gradually, and the injection rate at the heel end is greater than that at the toe end; due to the influence of heterogeneity, the injection volume along the horizontal section is distributed in multiple sections. Specifically, the higher the permeability is, the higher the injection volume in the section is. Field application shows that the new evaluation method can accurately characterize the distribution of injection volume along the horizontal section of horizontal water injection wells. Water control and oil stabilization measures are formulated based on this study, and the effectiveness has been proven by field application.