石油实验地质2026，Vol.48Issue(4)：849-859,11.DOI:10.11781/sysydz2026040849
川东南綦江地区深层煤层气储层特征及勘探方向
Reservoir characteristics and exploration targets of deep coalbed methane in the Qijiang area,southeastern Sichuan
摘要
Abstract
Against the backdrop of global energy transition,deep coalbed methane(CBM)at burial depths greater than 1 500 m has emerged as a highly promising unconventional natural gas resource.Multiple coal seams are developed in the Permian Longtan Formation in the Qijiang area,southeastern Sichuan.However,their reservoir characteristics remain poorly understood,and future exploration targets have yet to be clearly defined.To address these issues,reservoir characteristics,gas enrichment conditions and exploration targets of deep coal seams in the Longtan Formation were systemically investigated based on core observations,laboratory analyses and experi-mental data from multiple wells.As indicated by the research results,the Longtan Formation contains coal seams with large cumulative thickness and wide lateral distribution in research area.The coal rank is high-rank anthra-cite,with an average vitrinite reflectance of 2.93％.Measured gas contents range from 4 to 46.7 m3/t,with free gas accounting for approximately 18％-36％,indicating high gas contents and a relatively high proportion of free gas.The reservoirs are characterized by a dual pore-cleat system comprising micron-to nano-scale pores and cleats.Macropores account for 64.1％of the pore system,and pore-fracture connectivity is favorable.Clay minerals are dominated by illite/smectite mixed-layer minerals(averaging 68％).The reservoir exhibits low Young's modulus and high Poisson's ratio,indicating that stress-related risks should be carefully considered during hydraulic fracturing.Based on lithological assemblages,coal quality and preservation conditions,a three-category,twelve-parameter evaluation system was established,within which three favorable coal assemblage types were identified:thick coal seams,medium-thick coal seams interbedded with mudstone,and medium-thick coal seams interbedded with mudstone and sandstone.Accordingly,favorable areas covering approximately 5 243 km2 were delineated,with estimated geological resources of 1.38 × 1 012m3.The C4-C5-C6 coal-bearing assemblages in the 2nd member of the Longtan Formation(Longtan 2 Member)within the Guanshengchang Synclinorium,the plunging end of the Dingshan-Dongxi Structure,and the Lizi Gentle Fold Belt exhibit the most favorable geological conditions.These areas cover approximately 1 204.6 km2 and contain estimated geological resources of 316.2×108 m3,making them priority targets for future exploration.关键词
深层煤层气/储层特征/勘探方向/富集模式/綦江地区/川东南Key words
deep coalbed methane/reservoir characteristics/exploration targets/enrichment pattern/Qijiang area/southeastern Sichuan分类
能源科技引用本文复制引用
刘珠江,魏祥峰,陈斐然,王道军,魏富彬,郝景宇..川东南綦江地区深层煤层气储层特征及勘探方向[J].石油实验地质,2026,48(4):849-859,11.基金项目
国家自然科学基金企业创新发展联合基金(U24B6001)和中国石化科技部项目(P23221)联合资助. （U24B6001）
