Effect of Front Water Flooding Injection-Production Parameters on Polymer Flooding Recovery in a Conglomerate Reservoir

The conglomerate reservoir of the Xinjiang-552 oilfield is characterized by high heterogeneity and complex pore structure. After several years of water injection development, the formation pressure in the reservoir is low and the production per well is poor. The reservoir is difficult to regulate and control and does not meet the conditions for the implementation of the polymer flooding operations. In this paper, the numerical simulation method is applied to optimize the injection-production parameters, including the injection-production ratio, pressure recovery rate, reasonable production rate, and polymer injection timing of the polymer flooding in the X-552 reservoir. The objective of the research is to determine the optimal injection-production parameters and to provide sufficient injection-production capacity for polymer flooding. The front-water flooding technology is applied to ensure the successful progress of polymer flooding in the reservoir. The results show that when the reservoir formation pressure coefficient is 1.0 (the formation pressure is 16.4 MPa), the polymer flooding recovery is reasonably high, the front-water flooding injection time is 5 years, the injection-production ratio is 1.05, and the average annual pressure recovery rate is 0.52 MPa. As shown by the predicted results, the production profile and recovery degree are greatly improved, the development effect is satisfactory, and the goal of the frontal water flooding is achieved. The proposed method can be applied to provide guidance for front-water flooding in conglomerate-type reservoirs.