不同粒度构造煤的视电阻率特征  

Characteristics of apparent resistivity of coals with different particle sizes

作　　者：刘世奇[1,2] 高德燚 桑树勋[1,2] 王鹤 LIU Shiqi;GAO Deyi;SANG Shuxun;WANG He(Jiangsu Key Laboratory of Coal-based Greenhouse Gas Control and Utilization,China University of Mining and Technology,Xuzhou 221008,China;Carbon Neutrality Institute,China University of Mining and Technology,Xuzhou 221008,China;Key Laboratory of CBM Resources and Reservoir Strata Process State Ministry of Education,China University of Mining and Technology,Xuzhou 221116,China;School of Mineral Resource and Geoscience,China University of Mining and Technology,Xuzhou 221116,China)

机构地区：[1]中国矿业大学江苏省煤基温室气体减排与资源化利用重点实验室,江苏徐州221008 [2]中国矿业大学碳中和研究院,江苏徐州221008 [3]中国矿业大学煤层气资源与成藏过程教育部重点实验室,江苏徐州221116 [4]中国矿业大学资源与地球科学学院,江苏徐州221116

出　　处：《煤炭科学技术》2022年第12期162-169,共8页Coal Science and Technology

基　　金：国家自然科学基金资助项目(41727801,41972168)。

摘　　要：应力释放煤层气开发理论技术是构造煤煤层气开发的新技术方向,构造煤视电阻率的研究可以为应力释放煤层气开发提供构造煤识别的技术支撑。开展了单轴加载条件下,不同粒度构造煤的视电阻率与应力-应变监测试验,探讨了应力-应变过程中构造煤视电阻率变化规律与响应机制。结果表明,轴向载荷大于单轴抗压强度后,随载荷增大构造煤视电阻率呈负指数降低,至轴向载荷≥10 MPa时,视电阻率对载荷的敏感性降低;随粒度减小,构造煤视电阻率呈降低趋势,相同载荷下,粒度越小构造煤视电阻率对载荷的响应越敏感。受煤颗粒堆积方式和胶结类型影响,5~200目(4.000~0.075 mm)的构造煤具特殊性,其视电阻率整体较小、对载荷相对敏感。构造煤视电阻率随载荷的变化过程可划分为4个阶段。压密阶段,构造煤的视电阻率降幅取决于煤颗粒堆积方式和胶结类型;弹性阶段,粒度决定了构造煤视电阻率降幅,粒度越大,构造煤原有大孔和微裂隙保留越好,可压缩性越强,视电阻率降幅越高;扩容阶段,径向变形和微破裂导致构造煤视电阻率上升,构造煤力学强度则决定了视电阻率变化特征,随粒度减小,构造煤胶结强度和单轴抗压强度增大,视电阻率增幅降低;持续弹性阶段,破碎、压实作用使构造煤粒度分布更均匀、堆积更紧密,增强了电子导电性能,视电阻率降低。The theory and technology of stress released CBM development is a new theory and technology for CBM development of tectonically deformed coals. The research on the apparent resistivity of tectonically deformed coal can provide technical support for the identification of tectonically deformed coal for the stress release applied extraction of CBM. In this paper, the apparent resistivity and stressstrain monitoring experiments of tectonically deformed coals with different particle sizes were carried out under uniaxial loading, and the change law and response mechanism of the apparent resistivity in the stress-strain process were discussed. The results show that when the axial load is greater than the uniaxial compressive strength, the apparent resistivity of tectonically deformed coal decreases negatively exponentially with the increase of the axial load. When the axial load ≥10 MPa, the sensitivity of the apparent resistivity to the load decreases. With the particle size decreasing, the apparent resistivity of tectonically deformed coal decreases. Under the same axial load, the smaller the particle size is, the more sensitive the apparent resistivity of tectonically deformed coal is to the axial load. Affected by the accumulation mode and cementation type of coal particles, the structural coal of 5~200 mesh(4.000~0.075 mm) is special, with small apparent resistivity and relatively sensitive to load. The changes of apparent resistivity of tectonically deformed coal with axial load can be divided into four stages. In the compaction stage, the apparent resistivity decline of tectonically deformed coal depends on the accumulation mode and cementation type of coal particles. In elastic stage, particle size determines the apparent resistivity decline of tectonically deformed coal. The larger the grain size is, the better the original macropores and microcracks of structural coal remain, the stronger the compressibility is, and the higher the apparent resistivity reduction is. In the dilatation stage, radial deformation

关 键 词：构造煤 轴向载荷 胶结类型 单轴抗压强度 弹性极限 糜棱煤 视电阻率 

分 类 号：TE37[石油与天然气工程—油气田开发工程]