低渗透煤层转向压裂裂缝扩展规律的扩展有限元模拟研究  

Finite Element Simulation of Fracture Propagation Path During Oriented Perforation Steering Fracturing in Low Permeability Coal Seam

作　　者：郭辉 王新萍[2] GUO Hui;WANG Xinping(Department of Safety Engineering,Shanxi Institute of Energy,Taiyuan 030024,China;Department of Computer Engineering,Shanxi Polytechnic College,Taiyuan,030024,China)

机构地区：[1]山西能源学院安全工程系,山西太原030024 [2]山西职业技术学院计算机工程系,山西太原030024

出　　处：《煤矿安全》2020年第11期189-194,共6页Safety in Coal Mines

基　　金：山西省自然科学基金资助项目(2014011035-2)。

摘　　要：为明确煤层定向射孔转向压裂改造过程中裂缝扩展轨迹及其偏转距离的变化规律,基于ABAQUS软件平台,采用扩展有限元法(XFEM)对煤层中的转向压裂过程进行了数值模拟,以沁水盆地南部柿庄区块的煤层为例,研究了射孔方位角、水平地应力差、注液参数(压裂液黏度及排量)对转向压裂过程中裂缝的起裂压力和转向距离的影响规律。结果表明:裂缝起裂压力随射孔方位角与水平地应力差的增加基本呈线性规律增大,随压裂液排量的增大基本呈对数规律升高,压裂液黏度对裂缝起裂压力的影响几乎可以忽略;裂缝转向距离随射孔方位角与压裂液排量的增大基本呈线性规律增大,随水平地应力差与压裂液黏度的增加呈线性规律减小。In order to clarify the fracture propagation track and the variation rule of deflection distance in the course of directional perforation turning fracturing in low permeability coal seam,based on ABAQUS platform,the deflection process of the hydraulic fracture in coal seam is simulated by extended finite element.Taking the coal seam of Shizhuang block in the south of Qinshui Basin as an example,the effects of horizontal in situ stress difference,perforation parameters,injection parameters on formation fracture pressure and deflection distance in the process of oriented perforation steering fracturing are studied.The results show that,the formation fracture pressure increases linearly with the increase of perforation azimuth and horizontal in-situ stress difference,and logarithmically with the increase of fracturing fluid displacement.The viscosity of fracturing fluid has little effect on formation fracture pressure.The fracture deflection distance increases linearly with the increase of perforation azimuth and fracturing fluid displacement,and decreases linearly with the increase of horizontal in-situ stress difference and fracturing fluid viscosity.

关 键 词：低渗透煤层 定向射孔 转向压裂 扩展有限元 数值模拟 

分 类 号：TD712[矿业工程—矿井通风与安全]