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水平井结合体积压裂改造成为目前开发致密油藏的关键技术。考虑到致密油藏多尺度渗流(基质、天然裂缝和水力裂缝)及多种流动机理(启动压力梯度和应力敏感)相互耦合的复杂渗流过程,该文建立了综合考虑致密油藏启动压力梯度和应力敏感的体积压裂水平井不稳定压力分析模型。通过Laplace变换和摄动变换等求解得到了拉氏空间中的井底压力,应用Stehfest数值反演绘制了相应的压力动态响应曲线。研究结果表明:压力响应曲线可以划分为6个流动阶段,模型的退化结果与Ozkan模型一致,验证了该文模型的正确性,并在此基础上进行了影响因素分析。该文研究结果可为致密油藏体积压裂水平井的不稳定压力分析提供一定的理论依据。
The combination of horizontal well and volumetric fracturing has become the key technology for developing tight reservoirs. Considering the complex seepage process of multi-scale seepage flow (matrix, natural fractures and hydraulic fractures) and various flow mechanisms (starting pressure gradient and stress sensitivity) coupled with each other in tight reservoirs, Stress - sensitive Volume Fracturing Horizontal Well Unsteady Pressure Analysis Model. The bottom hole pressure in Laplace space was obtained through Laplace transform and perturbation transformation. The corresponding dynamic response curve of pressure was obtained by Stehfest numerical inversion. The results show that the pressure response curve can be divided into six stages. The degradation results of the model are consistent with those of the Ozkan model. The correctness of the model is verified and the influencing factors are analyzed. The results of this paper can provide some theoretical basis for the analysis of unsteady pressure in fractured horizontal wells in tight reservoirs.