径向井立体压裂裂缝扩展数值模拟  

Numerical simulation of three-dimensional fracturing fracture propagation in radial wells

作　　者：王天宇[1] 郭肇权 李根生[1] 马正超 雍煜宁 常鑫 田守嶒[1] WANG Tianyu;GUO Zhaoquan;LI Gensheng;MA Zhengchao;YONG Yuning;CHANG Xin;TIAN Shouceng(State Key Laboratory of Petroleum Resources and Prospecting,China University of Petroleum,Beijing 102249,China;Beijing Petroleum Machinery Co.,Ltd.,China National Petroleum Corporation Engineering Technology Research Institute,Beijing 102206,China;State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan 430071,China)

机构地区：[1]中国石油大学(北京)油气资源与探测国家重点实验室,北京102249 [2]中国石油集团工程技术研究院北京石油机械有限公司,北京102206 [3]中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室,武汉430071

出　　处：《石油勘探与开发》2023年第3期613-623,共11页Petroleum Exploration and Development

基　　金：国家自然科学基金重大科研仪器研制项目“水力喷射径向水平井综合试验系统”(51827804);中国石油战略合作科技专项项目“强非均质砾岩油藏径向井复合压裂理论与技术研究”(ZLZX2020-01-04);岩土力学与工程国家重点实验室开放基金课题“页岩油储层径向井立体压裂裂缝起裂与扩展规律研究”(SKLGME021024)。

摘　　要：基于有限元-无网格法,考虑压裂液流动与岩石基质变形的耦合作用,建立了径向井压裂裂缝扩展数值模型,模拟了径向井压裂裂缝形态,定量表征了径向井对裂缝的诱导作用,揭示了方位夹角、水平主应力差与岩石基质渗透率等对裂缝形态演化的影响机制。研究表明,同层双分支径向井压裂时径向井间存在挤压作用,当径向井沿最小水平主应力方向对称分布且方位夹角大于15°时,挤压作用减小了径向井的裂缝引导长度,当径向井沿最大水平主应力方向对称分布时,挤压作用增大了径向井的裂缝引导长度。裂缝形态由径向井的纠偏作用、径向井间的挤压作用与最大水平主应力的偏转作用共同控制。当径向井沿最小水平主应力方向对称分布时,径向井的裂缝引导长度随着方位夹角的增大逐渐减小,当径向井沿最大水平主应力方向对称分布时,径向井的裂缝引导长度随着方位夹角的增大先减小后增大。径向井的裂缝引导长度随水平主应力差的增大而减小。岩石基质渗透率增大,径向井周围基质的孔隙压力增大,对裂缝的诱导作用增强。A fracture propagation model of radial well fracturing is established based on the finite element-meshless method.The model considers the coupling effect of fracturing fluid flow and rock matrix deformation.The fracture geometries of radial well fracturing are simulated,the induction effect of radial well on the fracture is quantitatively characterized,and the influences of azimuth,horizontal principle stress difference,and reservoir matrix permeability on the fracture geometries are revealed.The radial wells can induce the fractures to extend parallel to their axes when two radial wells in the same layer are fractured.When the radial wells are symmetrically distributed along the direction of the minimum horizontal principle stress with the azimuth greater than 15°,the extrusion effect reduces the fracture length of radial wells.When the radial wells are symmetrically distributed along the direction of the maximum horizontal principal stress,the extrusion increases the fracture length of the radial wells.The fracture geometries are controlled by the rectification of radial borehole,the extrusion between radial wells in the same layer,and the deflection of the maximum horizontal principal stress.When the radial wells are distributed along the minimum horizontal principal stress symmetrically,the fracture length induced by the radial well decreases with the increase of azimuth;in contrast,when the radial wells are distributed along the maximum horizontal principal stress symmetrically,the fracture length induced by the radial well first decreases and then increases with the increase of azimuth.The fracture length induced by the radial well decreases with the increase of horizontal principal stress difference.The increase of rock matrix permeability and pore pressure of the matrix around radial wells makes the inducing effect of the radial well on fractures increase.

关 键 词：径向井 立体压裂 裂缝扩展模拟 有限元-无网格法 流固耦合 

分 类 号：TE357[石油与天然气工程—油气田开发工程]