废弃煤矿采空区煤层气资源评价模型及应用

如何评价废弃煤矿采空区煤层气资源是其开发中遇到的关键问题。在对煤炭开采覆岩变形破坏规律研究的基础上，通过理论分析和数学推导，建立了废弃矿井煤层气资源量评价模型和方法，对山西晋煤集团晋圣煤矿采空区煤层气资源进行了评价。研究结果表明，煤炭开采导致采场周围岩体应力重新分布，引起煤层顶底板岩体发生变形与破坏。采空区煤层气资源主要由吸附气和游离气组成，主要来源于煤柱及残留煤层、临近未采煤层和围岩中的游离气和吸附气。基于采动覆岩变形破坏分带特征，根据破碎岩体孔隙率和碎胀系数关系，分别建立了采空区垮落带和断裂带内岩体孔隙体积模型。结合煤层气资源在废弃矿井中的分布特征，考虑煤炭开采采空区积水情况，建立了采空区积水量计算和含水饱和度计算模型，提出了废弃矿井煤层气资源量计算方法，对山西晋煤集团晋圣煤矿采空区煤层气资源进行了评价分析，评价结果认为，废弃煤矿采空区煤层气资源丰富，井田面积为6.5 km2，二叠系山西组3号煤层煤层气总资源量为5.871 7×108m3，其中吸附气资源5.835 3×108m3，游离气资源0.036 4×108m3，资源丰度为0.902 0×108m3/km2。

Evaluation model of CBM resources in abandoned coal mine and its application

How to evaluate the CBM resources in abandoned coal mines has become a key issue for development.On the basis of study on the deformation and failure law of overlying strata in coal mining,the authors set up an evaluation model and method for evaluating the CBM resources in abandoned coal mines through theoretical analysis and mathematical deduction.In particular,the CBM resources in Jinsheng mine goaf,which belongs to Shanxi Jincheng Anthracite Mining Group Ltd.,China,have been evaluated using the evaluation model.Results show that the deformation and failure of the rock mass in coal seam roof,and the stress redistribution of the surrounding rock mass have been caused by coal mining.The CBM resources in abandoned coal mines are mainly composed of adsorbed and free gas from coal pillar,residual coal and surrounding rock.Based on the deformation and failure characteristics of overburden rock and the relationship between porosity and expand coefficient of fractured rock mass,the pore volume models of caving and fracture zones in goaf are established separately.Considering the distribution characteristics of CBM resources and flooded situation in abandoned coal mines,the calculation models of water volume and saturation are also established.Also,the evaluation results show that the abandoned coal mines are abundant of CBM resources,with a coal mine area of 6.5 km2and a total CBM resource of 5.871 7×108m3 in coal seam No.3 of Shanxi Group,Permian.The volume of adsorbed gas is 5.835 3×108m3and free gas is 0.036 4×108m3,and the resource abundance is 0.902 0×108m3/km2.