致密油藏体积压裂水平井压力特征

Pressure characteristics for volume-fractured horizontal well in tight oil reservoirs

王欢 计秉玉 廖新维 伦增珉 吕成远 王友启1

中国石化石油勘探开发研究院，北京 100083 中国石油大学（北京），北京 102249

Petroleum Exploration and Production Research Institute, SINOPEC, Beijing 100083, China China University of Petroleum, Beijing 102249, China

为研究致密油藏水平井体积压裂改造后的储层和渗流特征，文中建立了考虑基质应力敏感性的体积压裂水平井复合试井模型。内区为压裂改造区，由多级压裂水力裂缝与双孔介质模型共同表征；外区为非改造区，由单孔介质模型表征。应用叠加原理、Laplace变换、Stehfest数值反演和摄动变换技术进行求解，得到了体积压裂水平井试井模型的井底压力特征曲线。研究结果表明，体积压裂水平井的渗流可以划分为裂缝双线性流、垂直于裂缝的线性流、裂缝拟径向流等7个特征阶段。敏感性参数分析表明，致密储层的应力敏感特征在试井解释中不可忽视，渗透率模数、储容比、窜流系数、水力裂缝条数和水力裂缝导流能力对压力和压力导数特征曲线会产生较大的影响。

Based on the characteristics of the reservoir and fluid flow after hydraulic volume fracturing of horizontal well, as well as considering the stress-sensitive characteristics of the tight oil reservoir, the composite well test model is established. The inner zone represents the stimulated reservoir volume region and is characterized by the multistage hydraulic fractures and dual-porosity model, while the outer zone represents the un-stimulated reservoir volume region and is modeled as a single porosity reservoir. The model is solved by the method of superposition, Laplace integral transformation, Stehfest numerical inverse algorithm, and the perturbation technique. Thus the characteristic curve of the well bottom pressure of the model is obtained. The results show that the flow regimes of the hydraulic volume-fractured horizontal well can be divided into 7 stages, including the fracture bilinear flow, the linear flow perpendicular to the fracture, fracture pseudo radial flow. The analysis of sensitivity parameters shows that the stress sensitive characteristic of the tight reservoir cannot be neglected in well test interpretation. The permeability modulus, storage ratio, inter-porosity flow coefficient, hydraulic fracture number and conductivity have a greater impact on the pressure and pressure derivative characteristics.

10.6056/dkyqt202002016