致密油藏压裂水平缝不稳态压力分析

Analysis of Unsteady Pressure of Fractured Horizontal Joints in Tight Reservoir

基于有限导流水平裂缝及势叠加理论,在水平裂缝壁面上进行耦合,得到不稳态压力分析模型。研究了流压变化规律,并将流动阶段划分为:裂缝内径向流动、油藏内线性流动、油藏内早期拟径向流动和油藏内晚期径向流动4个阶段;研究了不同因素对压力传播的影响,研究表明:随着油层厚度增加,油藏内垂向线性流动阶段持续时间延长,油藏内早期拟径向流动阶段出现推迟且时间延长;随着裂缝导流能力增加,裂缝内径向流动阶段时间缩短,油藏内垂向线性流动阶段持续时间延长;随着水垂比增加,油藏内垂向线性流动阶段和油藏内早期拟径向流动阶段持续时间都缩短,流动更快地进入晚期径向流动阶段。

Based on the finite conductivity horizontal crack and potential superposition theory, the coupled model is obtained on the wall surface of the horizontal crack. Flow pressure is studied, and the mobile phase is divided into four stages： Cracks in radial flow, linear flow in reservoir, reservoir in early pseudo radial flow and reservoir in the late radial flow. The effects of different factors on the pressure propagation are studied, which shows that with the increase of the thickness of oil reservoir, vertical linear flow duration, reservoir in early stage and quasi radial flow are delayed. With the increase of fracture flow capacity, crack radial flow stage time, reservoir vertical linear flow stage duration are prolonged. With the water vertical ratio increases, the vertical flow in the reservoir and reservoir in the early stage of linear pseudo radial flow duration are shortened, and flow more quickly into the late stage of radial flow.