水力压裂的天然裂缝延伸简单模型

Simple model for natural fracture propagation through hydraulic fracturing

 刘顺¹ 何衡² 王俊奇¹ 周德胜¹

西安石油大学石油工程学院，陕西 西安 710065 中国石油长庆油田分公司油气工艺研究院，陕西 西安 710021）

School of Petroleum Engineering, Xi′an Shiyou University, Xi′an 710065, China Research Institute of Oil and Gas Technology, Changqing Oilfield Company, PetroChina, Xi′an 710021, China)

 针对现代网状压裂裂缝间相互沟通时影响因素认识不清的问题，给出了天然裂缝与水力裂缝正交时，天然裂缝延伸长度与入口压力的简单计算模型。通过差分数值法进行求解，对注入流体与储层物性对天然裂缝的影响进行了详细分析。结果表明：天然裂缝的入口压力和延伸长度，与天然裂缝宽度、注入流体黏度及初始入口压力有关；注入流体流量越大、距离水力裂缝越近、储层弹性模量越大，则天然裂缝入口压力越大，天然裂缝延伸也越长。该简单模型可为天然裂缝沟通延伸的快速设计提供理论依据。

 Since the factors that affect the fracture connecting are not understood very well in hydraulic fracturing, the simple calculation model for natural fracture propagating and the injection pressure is proposed when the natural fracture is orthogonal to man-made fracture. Using difference numerical method, the injected fluid and reservoir characteristics that affect natural fracture propagation are analyzed. The results show that natural fractures inlet pressure curve is related to the natural fracture width, the injection fluid viscosity, and the initial injection pressure; the greater the injecting fluid flow rate, the closer the hydraulic fracture from the natural fractures, and the greater the Young′s modulus of reservoirs, the higher the natural fracture inlet pressure and the longer the extended length. This simple model can provide theory basis for quick design for natural fracture′s propagation.

10.6056/dkyqt201604017