东营凹陷陆相页岩油强化缝网改造生产制度优化研究

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

为最大限度提高东营凹陷陆相页岩油水平井全生命周期累计采油量,开展了强化缝网改造合理生产制度研究。针对页岩油藏复杂的赋存和渗流机理,建立了页岩油藏双重介质两相流压–闷–采全周期流动表征模型,模拟研究了不同生产制度下(即不同闷井时间、自喷期和机采期的压降速度)的产量变化规律,初步探讨了生产制度的优化方法。根据模拟结果,得到了目标井的合理生产制度:闷井时间为60 d;自喷初期压降速度控制在0.06~0.10 MPa/d,自喷中期压降速度控制在0.02~0.04 MPa/d,自喷末期放液生产,快速将油压降至0;机采期控制压降速度保证油井持续生产,防止压力快速下降,地层基质供液不足。研究结果为优化东营凹陷陆相页岩油开发方案提供了理论依据,也为其他地区优化页岩油水平井生产制度提供了借鉴。

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.