鄂尔多斯盆地中东部深层煤层气成藏富集规律  

Enrichment law of deep coalbed methane accumulation in central and eastern Ordos Basin

作　　者：张道锋[1] 王冰[1] 王华[1,2] 郑小鹏[1] 黄锦袖[3] ZHANG Daofeng;WANG Bing;WANG Hua;ZHENG Xiaopeng;HUANG Jinxiu(Research Institute of Exploration and Development,PetroChina Changqing Oilfield Company,Xi’an 710018,China;National Engineering Laboratory of Low-Permeability Oil&Gas Exploration and Development,Xi’an 710018,China;Development Department of Gas Field,PetroChina Changqing Oilfield Company,Xi’an 710018,China)

机构地区：[1]中国石油长庆油田公司勘探开发研究院,陕西西安710018 [2]低渗透油气田勘探开发国家工程实验室,陕西西安710018 [3]中国石油长庆油田公司气田开发事业部,陕西西安710018

出　　处：《西安科技大学学报》2024年第6期1165-1175,共11页Journal of Xi’an University of Science and Technology

基　　金：中国石油天然气股份有限公司攻关性应用性科技项目(2023ZZ1804);国家科技重大专项(2016ZX05050)。

摘　　要：鄂尔多斯盆地上古生界煤层广泛发育,深部煤层气资源十分丰富。为明确鄂尔多斯盆地深部煤储层的地质特征以及含气规律,优选煤层气富集有利区,以鄂尔多斯盆地中东部8号煤为研究对象,综合利用地质、分析测试以及生产数据等资料,分析了深部煤岩储层地质特征和含气性特征。结果表明:8号煤在中-东部地区发育厚度大、西部和南部厚度小,煤岩类型以光亮煤和半亮煤为主,显微组分以镜质组含量处于绝对优势,有利于煤层气的生成和储集;盖层以泥岩和灰岩为主,保存条件较好;煤岩孔隙成因类型包括植物组织孔、气泡孔和晶间孔,局部发育张性裂隙,孔隙大小以微孔和大孔为主;煤储层含气量具有中东部高、西部地区低的特征,煤层含气量随埋深增大呈现“先增大后减小”的趋势,深部煤层游离气占比超过30%;构建了包括含气量、煤层厚度、埋深、宏观煤岩类型、泥质含量以及煤体结构6参数的评价指标体系,在3个先导试验区内划分出Ⅰ类和Ⅱ类煤层气富集有利区。研究成果可为深层煤层气有利区优选和高效开发提供指导。The Upper Paleozoic coal seams are widely developed in Ordos Basin,and deep coalbed methane(CBM)resources are very rich.To clarify the geological characteristics and gas bearing laws of deep coal reservoirs in Ordos Basin,and to select favorable areas for coalbed methane enrichment,the study focuses on the No.8 coal seam in the central and eastern Ordos Basin.By comprehensively utilizing geological,analytical and production data,the geological characteristics and gas bearing characteristics of deep coal reservoirs were analyzed.The results show that No.8 coal seam is characterized by larger deposition thickness in the middle and east,and smaller deposition thickness in the west and south.Coal rocks are mainly composed of bright coal and semi-bright coal.Cap rocks are mainly composed of mudstones and limestones,with good preservation conditions.The genetic types of coal pores include plant tissue pore,bubble pore and intercrystalline pore.Tensile fractures are developed locally,and the pore size is mainly micropores and macropores.The CBM content is high in central and eastern regions and low in western regions.The gas content shows a trend of “first increasing and then decreasing” with increasing burial depth.The higher formation temperature promotes the conversion of adsorbed gas to free gas,resulting in more than 30% for free gas in coal reservoir.The evaluation system,composed of such six parameters as gas content,thickness of coal seam,buried depth,macroscopic coal-rock type,shale content and coal body structure,has been established.The favorable areas of CBM in Type Ⅰ and Ⅱ have been classified in the three pilot test areas.The research can provide guidance for the optimization of favorable areas and efficient development of deep CBM.

关 键 词：深层煤层气 地质特征 有利区 鄂尔多斯盆地 

分 类 号：TE121[石油与天然气工程—油气勘探]