页岩气藏流固耦合缝网扩展机理研究

项目名称： 页岩气藏流固耦合缝网扩展机理研究

项目编号： No.51504204

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 矿业工程

项目作者： 赵志红

作者单位： 西南石油大学

项目金额： 21万元

中文摘要： 缝网压裂是页岩气藏勘探开发的关键技术，水力裂缝与天然裂缝交互延伸是缝网形成的基础，本项目综合应用石油工程、断裂力学、渗流力学和数学等学科理论，首先开展天然裂缝滤失实验和裂缝交互延伸实验，然后应用流体力学理论，建立压裂液二维滤失模型和缝内压力分布模型；考虑压裂液的滤失，应用位移不连续方法，建立水力裂缝诱导应力场模型，将流体与应力有机耦合起来；在相交前，建立复合应力场作用下的天然裂缝破坏模型；在此基础上，建立考虑水力裂缝与天然裂缝相互作用全过程的交互延伸模型，应用现代数学理论建立数值解，形成水力裂缝和天然裂缝交互延伸定量描述方法，分析排量、压裂液性质、岩石力学参数和天然裂缝性质等因素影响缝网的规律，指导页岩气藏缝网压裂设计，促进页岩气缝网压裂理论的进步。

中文关键词： 缝网扩展；水力压裂；流固耦合；应力干扰；页岩气

英文摘要： Network fracturing is a key technology for shale gas exploration and development. Interaction between hydraulic fracture and natural fractures is the basis for the formation of fracture network. By integrated application of petroleum engineering, fracture mechanics, percolation theory and mathematics, this project will study several aspects pertaining to this the topic. Firstly, leakoff experiment will be carried out and two dimensional leakoff models are then developed. By utilization of fluid mechanics theory, pressure distribution for fracture network could be achieved. Based on the displacement discontinuity method, model of hydraulic fracturing induced stress field could be achieved. With application of the superposition principle, three dimensional natural fracture stress field could be calculated by considering leakoff induced stress, hydraulic induced stress and In-situ stress field. Before intersecting with hydraulic fracture, model of natural fracture damage under the condition of compound stress field will be established. Then considering stress concentration at hydraulic fracture tip, models for natural fracture shear, open, and cross will be established. Finally, model of hydraulic fracture propagating along natural fractures is established by considering the pressure drop, fracturing fluid leakoff, etc. Modern mathematical methods will be used to solve the models. The influence of several factors on fracture network will be studied, including pumping rate, fracturing fluid properties, rock mechanics parameters and natural fracture properties. The project provides guidance to the fracture network design optimization and set up a theoretical basis for the fracture network simulation model.

英文关键词： Network extension;Hydraulic fracturing;fluid-structure interaction;Stress interference;Shale gas