鄂尔多斯盆地东部二叠系山西组煤系气成藏地质条件与资源潜力预测  

Gas accumulation conditions and resource potential in coal measure strata of the Permian Shanxi Formation in the eastern Ordos Basin

作　　者：张春林[1] 张嘉琪 宋泽章 姜福杰[2,3] 范立勇[4] 裴煜 Zhang Chunlin;Zhang Jiaqi;Song Zezhang;Jiang Fujie;Fan Liyong;Pei Yu(PetroChina Research Institute of Petroleum Exploration&Development;State Key Laboratory of Petroleum Resources and Prospecting;College of Geosciences,China University of Petroleum(Beijing);PetroChina Changqing Oilfield Company)

机构地区：[1]中国石油勘探开发研究院 [2]油气资源与探测国家重点实验室 [3]中国石油大学(北京)地球科学学院 [4]中国石油长庆油田公司

出　　处：《中国石油勘探》2021年第6期110-124,共15页China Petroleum Exploration

基　　金：国家科技重大专项“大气田富集规律与勘探关键技术”(2016ZX05007-002);中国石油天然气股份有限公司重大科技项目“大中型气田(区)勘探关键技术及目标评价”(2019B-0606)。

摘　　要：鄂尔多斯盆地上古生界二叠系山西组具有丰富的煤系气资源,分析煤系气成藏地质条件,预测其蕴藏的资源潜力,对深化盆地非常规天然气的勘探有重要意义。以鄂尔多斯盆地山西组为目的层,基于岩心观察和单井地层发育特征分析,结合扫描电镜、X射线衍射分析、气体吸附实验等一系列分析测试成果,详细研究了烃源岩的地质、地球化学特征与储层的矿物组分、孔隙结构、物性特征,进而分析煤系气成藏地质条件并进行资源潜力预测。研究结果表明:(1)山西组烃源岩纵向上单层厚度较薄、层数多,平面上东厚西薄,烃源岩有机碳含量高,有机质类型为Ⅱ_(2)、Ⅲ型,镜质组反射率介于1.2%~2.6%,处于高成熟—过成熟阶段,生气潜力大;(2)山西组砂岩储层以岩屑石英砂岩和岩屑砂岩为主,储集空间以岩屑溶孔为主,孔隙度主要分布在2%~10%;山西组泥岩的矿物组分以石英和黏土矿物为主,孔喉结构复杂,储集空间类型主要为有机质孔和微裂缝;(3)运用蒙特卡洛方法评价山西组各层段资源潜力,山西组煤系气概算资源量为306879.79×10^(8)m^(3),其中山2段资源潜力较大,煤系气资源量为177001.15×108m^(3)。The coal measure gas resources are abundant of the Permian Shanxi Formation of the Upper Paleozoic in Ordos Basin.Therefore,it is of great significance to analyze the gas accumulation conditions in coal measure strata and predict the gas resource potential,so as to deepen the exploration of unconventional gas in Ordos Basin.By taking Shanxi Formation as the study object,the geological and geochemical characteristics of source rocks and the mineral composition,pore structure,physical properties of reservoirs are studied in details in this study based on core observation and stratigraphic characteristics in single well,as well as a series of lab test results such as SEM,XRD analysis and gas adsorption experiments.Then the gas accumulation conditions of coal measure strata are analyzed and the gas resource potential is predicted.The results show that:(1)The source rocks of Shanxi Formation are characterized by relatively thin thickness of a single layer,multiple layers,thick in the east and thin in the west,high TOC,organic matter types of TypeⅡ_(2) andⅢ,high mature to over mature with R_(o) ranging from 1.2%-2.6%,and great gas generation potential;(2)The sandstone reservoir of Shanxi Formation is mainly composed of lithic quartz sandstone and lithic sandstone,and the reservoir space is dominated by dissolution pores of lithiclast with the porosity of 2%-10%;The mineral composition of mudstone is mainly quartz and clay mineral,and the reservoir space types include organic pores and micro fractures,with complex pore throat structure;(3)The estimated gas resource of Shanxi Formation is about 306879.79×10^(8)m^(3) by using the Monte-Carlo method,among which the 2^(nd) member of Shanxi Formation has large gas resource potential of 177001.15×10^(8)m^(3).

关 键 词：鄂尔多斯盆地 山西组 煤系气 成藏地质条件 资源潜力 

分 类 号：TE112[石油与天然气工程—油气勘探]