Production System Optimization for Enhanced Fracture Network Stimulation in Continental Shale Oil Reservoirs in the Dongying Sag

Abstract

The reasonable production system for enhanced fracture network stimulation was studied to maximize the cumulative production in the full period of continental horizontal shale oil wells in the Dongying Sag. According to the complex storage and seepage mechanisms of the shale oil reservoir, a model was established to characterize the full period of fracturing, shut-in and oil production of two-phase flow in the dual media in shale oil reservoir. Production variation with the different production systems (different shut-in time and pressure drop rates in the flowing and pumping stages), and the method for production system optimization were preliminarily discussed by simulation. According to the simulation results, a reasonable production system for target wells was obtained. To be specific, the reasonable shut-in time was 60 days; the pressure drop rate was controlled to be 0.06–0.10 MPa/d at the early flowing stage and 0.02–0.04 MPa/d at the middle flowing stage; tapping was carried out at the last flowing stage to rapidly release the oil pressure to 0; the pressure drop rate was controlled to ensure continuous production of oil wells at the pumping stage, avoiding insufficient liquid supply from the formation matrix due to excessively fast pressure drop. The research results can provide a theoretical guidance for development optimization of continental shale oil in the Dongying Sag, and also provide references for the optimization of production systems for horizontal shale oil wells in other regions.