径向井辅助前置液酸压裂缝扩展数值模拟  

Numerical simulation of fracture propagation guided by radial well assisted preflush acid fracturing

作　　者：齐宁[1] 甘俊冲 章泽辉 刘毅龙 申玉洋 刘练[3] QI Ning;GAN Junchong;ZHANG Zehui;LIU Yilong;SHEN Yuyang;LIU Lian(School of Petroleum Engineering in China University of Petroleum(East China),Qingdao 266580,China;Natural Gas Evaluation Project Department,PetroChina Changqing Oilfield Company,Xi̍an 710018,China;Northwest Oilfield Company,SINOPEC,Urumqi 830011,China)

机构地区：[1]中国石油大学(华东)石油工程学院,山东青岛266580 [2]中国石油长庆油田分公司天然气评价项目部,陕西西安710018 [3]中国石油化工股份有限公司西北油田分公司,新疆乌鲁木齐830011

出　　处：《中国石油大学学报（自然科学版）》2024年第3期101-110,共10页Journal of China University of Petroleum(Edition of Natural Science)

基　　金：国家自然科学基金项目(51874336)。

摘　　要：基于扩展有限元及双尺度连续模型理论建立径向井辅助前置液酸压裂缝扩展模型,引入偏离系数作为量化评价指标,分析各因素对裂缝形态的影响,并利用灰色关联分析方法明确主控因素。结果表明:径向井对前置液酸压裂缝扩展具有显著引导作用,裂缝优先沿径向井方向起裂并扩展一定距离,而后逐渐偏向最大水平主应力方向;径向井方位角、水平地应力差和地层弹性模量越小,径向井长度越长,偏离系数越小,径向井引导效果越好,其中水平地应力差为主控因素;当径向井方位角为15°时,前置液酸压裂缝沿着径向井方向扩展14.32 m后偏向最大水平主应力方向,径向井的引导效果最好,偏离系数为0.005。In this paper,a fracture propagation model of radial well assisted preflush acid fracturing was established based on the extended finite element method and the two-scale continuum model theory.The term "deflection factor" was introduced as the quantification criterion to analyze the influence of various factors on the fracture morphology,and the main control factors were identified by using the gray correlation analysis method.The simulation results show that the radial well has a significant guiding effect on the fracture propagation of the preflush acid fracturing.The fracture starts and expands for a certain distance along the radial well,and then gradually deflects to the direction of the maximum horizontal principal stress.Smaller azimuth of the radial well,horizontal in-situ stress difference and elastic modulus of rock and longer length of the radial well can cause smaller deflection factor and better guiding effect.The most important influence factor is the horizontal in-situ stress difference.For instance,when the azimuth of the radial well is 15°,the fracture can propagate 14.32 m along the radial well,and deflect to the direction of the maximum principal stress finally.In this case,the radial well has the best guiding effect,and the deflection factor is 0.005.

关 键 词：径向井 前置液酸压 裂缝扩展 扩展有限元 双尺度模型 

分 类 号：TE357.2[石油与天然气工程—油气田开发工程]