基于扩展有限元算法的裂缝转向扩展轨迹预测  

Trajectory prediction of crack turning propagation based on extended finite element algorithm

作　　者：王新萍[1] 张起贵 张润旭 WANG Xinping;ZHANG Qigui;ZHANG Runxu(Department of Computer Engineering,Shanxi Polytechnic College,Taiyuan,Shanxi 030024,China;College of Information and Computer Science,Taiyuan University of Technology,Taiyuan,Shanxi 030024,China;College of Mining Engineering,Taiyuan University of Technology,Taiyuan,Shanxi 030024,China)

机构地区：[1]山西职业技术学院计算机工程系,山西太原030024 [2]太原理工大学信息与计算机学院,山西太原030024 [3]太原理工大学矿业工程学院,山西太原030024

出　　处：《燕山大学学报》2020年第2期182-188,共7页Journal of Yanshan University

基　　金：国家自然科学基金资助项目(51974192,41902179);山西省研究生创新基金资助项目(800104-02100675)。

摘　　要：针对常规算法难以准确预测煤层转向压裂过程中裂缝跳跃式、不连续偏转的问题,提出采用计算精度高、计算量小且在解决局部特征问题和模拟各种不连续性传播方面具有显著优势的扩展有限元算法模拟煤层转向压裂过程,实现对裂缝轨迹的精准预测。通过有限元离散化的方法得到了转向压裂过程的扩展有限元模型。基于ABAQUS软件平台,采用扩展有限元算法对转向压裂试验的裂缝轨迹进行了预测,并与试验结果进行了对比分析;采用扩展有限元与有限元算法对现场压裂的裂缝轨迹进行了预测,并与现场微震监测数据进行了对比分析。结果表明,采用扩展有限元算法预测的裂缝轨迹为关于注液点对称的双翼型裂缝;裂缝在射孔端起裂后逐渐发生偏转直到与最大水平地应力方向一致,偏转幅度先增后减;扩展有限元算法预测的裂缝轨迹与压裂试验结果及现场微震监测点具有较高的匹配性,证明了该算法的准确性与可靠性。Aiming at the problem that the conventional algorithm is difficult to accurately predict the fracture jump and discontinuous deflection in the process of coal seam steering fracturing, the extended finite element algorithm was applied to simulate the process of coal seam steering fracturing and realize the accurate prediction of fracture trajectory.The extended finite element algorithm not only has high calculation accuracy and small calculation amount, but also has significant advantages in solving local characteristic problems and simulating the propagation of various discontinuities. The extended finite element model of steering fracturing process is obtained by the method of finite element discretization.Based on ABAQUS software platform and extended finite element algorithm, the fracture trajectories of steering fracturing test and field fracturing are predicted respectively, and compared with the test results and field micro seismic monitoring data.The results show that the fracture trajectory predicted by extended finite element algorithm is a double wing fracture with symmetrical injection point. After fracture initiation, the fracture deflects gradually until it is consistent with the direction of the maximum horizontal in-situ stress, and the deflection amplitude increases first and then decreases. The fracture trajectory predicted by extended finite element algorithm matches well with the fracture test results and micro seismic monitoring points, which proves the accuracy and reliability of the algorithm.

关 键 词：扩展有限元算法 煤层 转向压裂 轨迹预测 数值模拟 

分 类 号：TP15[自动化与计算机技术—控制理论与控制工程]