Unconventional Research Center, CNOOC Research Institute
Chinese Petroleum Society
School of Energy Resources, China University of Geosciences (Beijing)
Drilling and Production Research Department, CNOOC Research Institute

鄂尔多斯盆地东缘神府区块是典型深部煤层气田，资源丰富且勘探开发潜力巨大。2023年10月，神府深部煤层大气田成功申报探明地质储量超1100亿m3。府谷地区位于神府区块中部，是最早深部煤层气生产试验区，但目前对其煤层气的富集成藏规律和勘探开发潜力的认识尚不清楚。综合应用地震、测井、钻井和煤岩测试等资料以查明该地区深部煤层气地质特征、富集成藏规律和有利区分布。结果表明：主力煤层4+5、8+9号煤发育稳定且厚度较大(4+5号煤：3.2~5.8 m；8+9号煤：8.7~13.5 m)，有利层段主要分布在煤层中上部位置；宏观煤岩类型主要为光亮−半亮煤，煤体结构主要为原生−碎裂结构煤；受深成变质作用的影响，煤类以气煤、肥煤和焦煤为主，煤的变质程度处于热解生气的高峰期，煤储层表现出中−高含气量(4+5号煤：3.0~12.0 m3/t；8+9号煤：7.5~18.5 m3/t)和中−高含气饱和度(35.0%~115.0%)等特征；主力煤层属于低渗储层((0.01~0.09)×10−3 μm2)，孔隙结构主要以微孔和小孔为主。提出府谷地区煤层气为“挠褶−断层−水动力”富集成藏模式，煤层气富集区位于构造平缓区和斜坡带。建立深部煤层气地质−工程双甜点评价体系，识别出I类地质−工程甜点区位于东部和西南部，是研究区深部煤层气勘探开发首选区带。因此，该研究认识进一步丰富了深部煤层气富集成藏理论，对鄂东缘深部煤层气勘探开发实践具有重要指导意义。

The Shenfu block on the eastern margin of the Ordos Basin is a typical deep coalbed methane (CBM) field with abundant resources and considerable potential for exploration and exploitation. In October 2023, the large-scale Shenfu deep CBM field successfully reported proven geological reserves exceeding 110 billion m3. The Fugu area, located in the central part of the Shenfu block, is the earliest experimental area for deep CBM production. However, there is a lack of a clear understanding of CBM enrichment and accumulation patterns, as well as the potential for exploration and development, of this area. By comprehensively utilizing the data from seismic surveys, logging, drilling, and coal tests, this study identified the geological characteristics, enrichment and accumulation patterns, and favorable area distribution of deep CBM in the Fugu area. The results show that the dominant coal seams 4+5 and 8+9 exhibit stable distribution and large thicknesses (coal seams 4+5: 3.2‒5.8 m; coal seams 8+9: 8.7‒13.5 m), with favorable intervals primarily occurring in the middle-upper parts. Macroscopically, the coals are dominated by bright to semi-bright coals, and their structures predominantly include primary and cataclastic structures. Due to the influence of plutonic metamorphism, the coals mainly comprise gas coal, fat coal, and coking coal. Regarding the metamorphic degree, the coals are at the peak of pyrolysis and gas generation, with coal reservoirs exhibiting medium to high gas contents (coal seams 4+5: 3.0‒12.0 m3/t; coal seams 8+9: 7.5‒18.5 m3/t) and medium to high gas saturation (35.0%‒115.0%). The dominant coal seams are low-permeability reservoirs (permeability: (0.01‒0.09) ×10−3 μm2), with pores primarily consisting of micropores and small pores. This study proposed a CBM enrichment and accumulation mode involving flexural folds, faults, and hydrodynamic force, determining that the CBM enrichment areas include the gentle tectonic zone and the slope zone. Furthermore, this study established an evaluation system for geological and engineering double sweet spots of deep CBM, identifying that the Class I geological and engineering sweet spots are located in the eastern and southwestern parts, which serve as the preferred areas for deep CBM exploration and exploitation in the study area. This study further enriches the theory on deep CBM enrichment and accumulation, serving as an important guide for the exploration and exploitation of deep CBM on the eastern margin of the Ordos Basin.

中国海油集团公司重大科技项目(KJGG2022-1001) ；中国海油科技攻关项目(2023KT-FCG02)

郭广山，徐凤银，刘丽芳，等. 鄂尔多斯盆地府谷地区深部煤层气富集成藏规律及有利区评价[J]. 煤田地质与勘探，2024，52(2)：81−91.

GUO Guangshan，XU Fengyin，LIU Lifang，et al. Enrichment and accumulation patterns and favorable area evaluation of deep coalbed methane in the Fugu area, Ordos Basin[J]. Coal Geology & Exploration，2024，52(2)：81−91.