鄂尔多斯盆地深部8号煤储层孔隙发育模式及其控气作用  

Pore development patterns and gas control effects of No.8 deep coal seam of Ordos Basin

作　　者：黄道军[1] 许浩[2,3] 虎建玲 董煜 焦鹏帅 陈世达[2,3] 周国晓 吴小卓 武衡 HUANG Daojun;XU Hao;HU Jianling;DONG Yu;JIAO Pengshuai;CHEN Shida;ZHOU Guoxiao;WU Xiaozhuo;WU Heng(Exploration&Development Research Institute,PetroChina Changqing Oilfield Company,Xi’an 710018,China;School of Energy Resource,China University of Geosciences(Beijing),Beijing 100083,China;Coal Reservoir Laboratory of National Engineering Research Center of CBM Development&Utilization,China University of Geosciences,Beijing 100083,China)

机构地区：[1]中国石油长庆油田分公司勘探开发研究院,陕西西安710018 [2]中国地质大学(北京)能源学院,北京100083 [3]中国地质大学(北京)煤层气开发利用国家工程中心煤储层物性实验室,北京100083

出　　处：《煤炭科学技术》2025年第3期115-123,共9页Coal Science and Technology

基　　金：国家自然科学基金资助项目(42172188);中国石油天然气股份有限公司攻关性应用性科技专项资助项目(2023ZZ18);中国石油长庆油田公司重大科技专项资助项目(2023DZZ01)。

摘　　要：鄂尔多斯盆地内部深部8号煤分布广泛,煤阶跨度大,是勘探的主要目的层。然而,目前对于盆地内部深部煤储层的孔隙发育规律及其控制因素缺乏系统、全面的理解,尤其是在深部煤储层孔隙发育模式及其控气作用方面尚未进行深入研究。基于盆地内14口探井岩心测试分析数据,系统分析了煤储层的孔隙发育特征和发育模式,并探讨了其分布规律和控气作用。结果表明:随着变质程度增加,研究区8号深部煤储层微孔和介孔的孔体积均明显增高,宏孔体积逐渐降低。其中,微孔主要为气孔,尤以孔径为0.4~0.9 nm孔隙最为发育,介孔相对不发育。宏孔由中−低变质程度煤发育的胞腔孔和屑间孔转变为中−高变质程度煤发育的内生裂隙。由北到南随着变质程度的增加(R_(o,max)为0.60%~2.86%),盆地内8号深部煤储层孔隙发育模式可分为:宏孔发育型、双峰发育型和微孔发育型,其中,宏孔发育型煤储层含气量较低,但也含有一定比例的游离气;双峰发育型是盆地内8号深部煤储层的主要孔隙发育模式,该类型储层微孔、宏孔均较为发育,最有利于吸附气和游离气的富集与产出;微孔发育型煤储层吸附能力最强,含气性最优,资源潜力大,但渗透性较差,需采用极限压裂方式提升储层的渗透能力。The No.8 deep coal seam in Ordos Basin is widely distributed and spans a broad range of coal ranks,making it the primary target layer for exploration.However,a systematic and comprehensive understanding of the pore development patterns and their controlling factors in deep coal reservoirs within the basin is still lacking.In particular,there has been no in-depth research conducted on the pore development models and their gas-controlling effects in these deep coal reservoirs.Focusing on core test data from 14 exploratory wells within the basin,this study systematically examines the controlling factors and development patterns of pore structures in coal reservoirs and explores their distribution patterns and gas-controlling mechanisms.The results indicate that the pore volume of micropores and mesopores in the No.8 deep coal seam reservoirs of the study area increases significantly with the progression of coal metamorphism,while the pore volume of macropores decreases gradually.Micropores are predominantly composed of gas pores,with those in the 0.4−0.9 nm range being the most developed,whereas mesopores are relatively underdeveloped.Macropores are observed to transition from cellular pores and interclast pores in coal with low to medium metamorphic degrees to endogenetic fractures in coal with medium to high metamorphic degrees.From north to south with increasing metamorphic degree(R_(o,max)0.60%−2.86%),the pore development patterns of the No.8 deep coal seam are classified into three types:macropore-dominated,dual-peak,and micropore-dominated.Macropore-dominated reservoirs ex-hibit lower gas content but higher permeability,favoring free gas storage and coalbed methane production.Dual-peak reservoirs represent the predominant pore development pattern,where both micropores and macropores are well-developed,creating optimal conditions for ad-sorbed and free gas enrichment and production.Micropore-dominated reservoirs demonstrate the strongest adsorption capacity,superior gas content,and substantial resource pote

关 键 词：鄂尔多斯盆地 8号煤 变质程度 孔隙发育模式 控气作用 

分 类 号：P618.13[天文地球—矿床学]