The Selection of Plugging Technology for Polymer Flooding Production Wells in the PII4 to GI4+5 Reservoir Layers of the Block B

With the refined development of second-class and third-class, as well as thin and poor oil reservoirs, the conflicts between layers have become more pronounced. During the staged implementation of upward and downward polymer flooding development, a large number of injection-production wells require plugging of the previously developed formations. The selection of the plugging process needs to fully consider factors such as the formation systems, the integrity of the bore well channel, the duration of the plugging, the need for potential unplugging, and investment costs. The selection of plugging techniques must meet the requirements of tight sealing, maintaining passage, and being modifiable, considering whether unplugging is needed to restore the production layer during later-stage development, and avoiding technical constraints on the selection and implementation of various subsequent process measures. To address the challenges of poor plugging effectiveness and poor matching in process selection, By examining four different plugging methods commonly used in oilfields: the conventional mechanical plugging, the expandable tubular plugging, the chemical plugging, and the cement plugging, analyzing the working principles, the technological characteristics, the adaptability, the construction period, and the one-time investment costs. And formulated the principles for selecting plugging techniques for downward development production wells. Then following the principles for selecting plugging techniques for downward development production wells, guide the selection of plugging processes for polymer flooding production wells in the PII4 to GI4+5 oil reservoirs of Block B. The application demonstrates favorable effects in the PII4 to GI4+5 oil reservoirs of Block B. The research findings provide a reference basis for the design of industrial-scale polymer flooding plugging schemes in the future.