李亚坤, 王志荣, 胡凯, 等.考虑地下水害防治的水力压裂缝形态分布特征研究[J].河南理工大学学报（自然科学版）,2023,42(2):34-41.

LI Y K, WANG Z R, HU K,et al.Study on the morphological distribution features of hydraulic fractures considering underground water disaster control[J].Journal of Henan Polytechnic University(Natural Science) ,2023,42(2):34-41.

考虑地下水害防治的水力压裂缝形态分布特征研究

李亚坤, 王志荣, 胡凯, 陈玲霞

郑州大学 水利科学与工程学院，河南 郑州 450001

摘要:为深入探讨裂隙性储层水力压裂缝的穿隙特征及影响因素，基于RFPA2D有限元软件，根据焦作矿区煤岩测试结果，模拟岩石破裂过程，分析裂缝形成的主导因素；其次，运用ABAQUS中Cohesive单元，考虑裂缝尖端应力场和煤层内部原生裂隙系统的耦合作用，根据该矿区地质条件和二₁煤层物理力学参数，建立有限元分析模型，并进行压裂缝延伸的数值模拟。结果表明：不同地质条件下压裂缝延伸路径分为3种基本模式，即定向直线延伸、转向折线延伸和二次转向折线延伸；裂缝尖端应力差、原生裂隙发育特征是影响水力压裂缝形态与分布的关键因素。在应力差较小时，原生裂隙的力学性能对压裂缝分布形态起主导作用，随着应力差增大，其主导作用逐渐减弱。应力差过小、原生裂隙强度过弱，均易在原生裂隙处发生交叉转向，从而容易触及含水层，诱发各种地下水害。

关键词:穿隙水力压裂;RFPA2D软件;Cohesive单元;裂缝延伸特征;数值模拟

doi:10.16186/j.cnki.1673-9787.2020100066

基金项目:国家自然科学基金资助项目（41272339）；河南省自然科学基金资助项目（182300410149）

收稿日期:2020/10/27

修回日期:2021/05/18

出版日期:2023/03/25

Study on the morphological distribution features of hydraulic fractures considering underground water disaster control

LI Yakun, WANG Zhirong, HU Kai, CHEN Lingxia

School of Water Conservancy Engineering，Zhengzhou University，Zhengzhou 450001，Henan，China

Abstract:In order to further explore the penetration features and influencing factors of hydraulic fractures in fractured coal seam，the process of rock fracture was simulated according to the test results of coal and rock in Jiaozuo mining area with RFPA2D finite element software，and the dominant factors of fracture formation were analyzed.The Cohesive element in ABAQUS was adopted to establish the finite element analysis model in consideration of the coupling between the stress field at the crack tip and the primary fracture system in the coal seam according to the geological conditions of the mining area and the mechanical parameters of the coal seam，and the numerical simulation of the fracture extension was carried out.The results showed that there were three basic patterns of fracture extension paths under different geological conditions，namely，directional straight line extension，turning curve extension and secondary turning curve extension.The stress difference at the fracture tip and the development features of primary fractures were the key factors affecting the shape and distribution of hydraulic fractures.In case of small stress difference，the mechanical properties of the primary fracture played a dominant role in the distribution of fracture.With the increase of stress difference，its leading function gradually decreased.In case of excessively small stress difference and excessively weak strength of the primary fracture，it was easy to generate cross and turning at the primary fracture，which was inclined to touch the aquifer and induce various underground water disasters.

Key words:hydraulic fracturing through-crack;RFPA2D software;Cohesive element;fracture extension characteric;numerical simulation

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