中国低煤阶煤层气资源潜力及发展方向  

Resource potential and exploration targets of low-rank coalbed methane in China

作　　者：李勇[1,2] 郭涛[3,4] 刘欣妍[2] 彭苏萍 LI Yong;GUO Tao;LIU Xinyan;PENG Suping(State Key Laboratory for Fine Exploration and Intelligent Development of Coal Resources,China University of Mining and Technology(Beijing),Beijing 100083,China;College of Geoscience and Surveying Engineering,China University of Mining and Technology(Beijing),Beijing 100083,China;Exploration and Development Research Institute,East China Oil&Gas Company,SINOPEC,Nanjing,Jiangsu 210011,China;Key Laboratory of Deep Coalbed Methane Exploration and Development,SINOPEC,Nanjing,Jiangsu 210011,China)

机构地区：[1]中国矿业大学(北京)煤炭精细勘探与智能开发全国重点实验室,北京100083 [2]中国矿业大学(北京)地球科学与测绘工程学院,北京100083 [3]中国石化华东油气分公司勘探开发研究院,江苏南京210011 [4]中国石化深层煤层气勘探开发重点实验室,江苏南京210011

出　　处：《石油与天然气地质》2024年第6期1537-1554,共18页Oil & Gas Geology

基　　金：国家自然科学基金项目(42072194)。

摘　　要：中国低煤阶煤层气在西北和东北地区均有分布,主要赋存于侏罗系、白垩系和古近系,煤层数量多、厚度大但含气量低。埋深2000 m以浅低煤阶煤层气资源量约14.7×10^(12)m^(3),勘探开发潜力巨大。系统分析了中国4个典型盆地低煤阶煤层气资源情况,研究了不同埋深和地质组合条件下低煤阶煤层气的典型成藏特征和勘探开发潜力。结果表明:①中国低煤阶煤层气储层渗透性差(渗透率<1×10^(-3)μm^(2)),煤层水矿化度相对较高(>5000 mg/L);②基于构造、水动力场和温-压场协同驱动下的低阶煤层气成藏要素解剖,提出了“微相控煤、水文控烃、埋深控储、构造控藏”四元控气模式;③基于典型区带解剖,建立了6种低煤阶煤层气富集模式;④结合美国粉河盆地和澳大利亚苏拉特盆地低煤阶煤层气地质特征和开发实践,认为中国存在多薄煤系共聚和深部煤层气多元封存2种富集高产模式;⑤基于对低煤阶煤层气高效开发至关重要的煤岩条件、资源条件、保存条件、产出条件和可改造性等5种因素的分析,构建了煤层气选区评价方法及指标体系。未来勘探领域是盆地边缘山前逆掩断层下盘、盆地斜坡带深部-中部隆起区2大领域。The low-rank coalbed methane(CBM)is distributed in both the northwest and northeast regions of China,as dominated by the Jurassic,Cretaceous,and Paleogene with coal seams exhibiting large quantities and considerable thicknesses but low gas content.With resources estimated at approximately 14.7×10^(12)m^(3),the low-rank CBM at burial depths of 2000 m or less holds tremendous potential for exploration and production.Through a systematic analysis of low-rank CBM resources in four typical basins in China,we investigate the typical accumulation characteristics and the exploration and production potential of low-rank CBM under various burial depth-geology combinations.The results indicate that low-rank CBM reservoirs in China manifest low permeability(<1×10^(-3)µm^(2)),and relatively high salinity of coal seam water(>5000 mg/L).An analysis of the factors governing the accumulation of low-rank CBM under the synergistic effects of tectonism and hydrodynamic,temperature,and pressure fields reveals a gas enrichment-controlling pattern consisting of sedimentary microfacies-controlled coal occurrence,hydrogeology-controlled gas generation and preservation,burial depth-controlled reservoir properties,and tectonism-controlled gas accumulation.Six enrichment patterns of low-rank CBM are identified based on the analysis of typical zones.In combination with the geological characteristics and production practice of low-rank CBM in the Powder River Basin of the United States and the Surat Basin of Australia,we propose two enrichment patterns of low-rank CBM in China featuring high productivity,that is,the accumulation of gas from multiple single thin-bedded coal seams and deep CBM multiple factor-controlled storage.An assessment methodology and index system for the selection of CBM target areas are developed based on the analysis of five crucial factors for the efficient production of low-rank CBM:coal composition,resource potential,preservation conditions,production conditions,and fracability.Future exploration targets include

关 键 词：资源潜力 成藏模式 控气要素 选区评价体系 低煤阶煤层气 勘探方向 

分 类 号：TE132.2[石油与天然气工程—油气勘探]