鄂尔多斯盆地庆城地区延长组7段致密油特征及油源分析  

Tight oil characteristics and source analysis of the 7th Member ofthe Triassic Yanchang Formation in Qingcheng area, Ordos Basin

作　　者：屈童 高岗[1,2] 梁晓伟[3,4] 孙明亮[1,2] 尤源[3,4] 李涛涛 冯顺彦[3,4] 刘艳妮[3,4] 费国勇[5] QU Tong;GAO Gang;LIANG Xiaowei;SUN Mingliang;YOU Yuan;LI Taotao;FENG Shunyan;LIU Yanni;FEI Guoyong(College of Geosciences,China University of Petroleum(Beijing),Beijing,102249;State Key Laboratory of Petroleum Resources and Prospecting,China University of Petroleum(Beijing),Beijing,102249;Exploration and Development Research Institute of PetroChina Changqing Oilfield Comlpany,Xi’an,710018;National Engineering Laboratory for exploration and development of low permeability oil and gas fields,Xi’an,710018;Yumen Oilfield Exploration and Development Research Institute,Jiuquan,Gansu,735019)

机构地区：[1]中国石油大学(北京)地球科学学院,北京102249 [2]中国石油大学(北京)油气资源与探测国家重点实验室,北京102249 [3]中国石油长庆油田分公司勘探开发研究院,西安710018 [4]低渗透油气田勘探开发国家工程实验室,西安710018 [5]玉门油田勘探开发研究院,甘肃酒泉735019

出　　处：《地质论评》2023年第4期1313-1328,共16页Geological Review

基　　金：国家科技重大专项“鄂尔多斯盆地致密油资源潜力、甜点预测与关键技术应用”(编号:2016ZX05046005-002)的成果~~。

摘　　要：鄂尔多斯盆地三叠系延长组7段(长7段)半深湖—深湖相优质油源岩是油气的重要来源,包括黑色页岩和暗色泥岩,作为盆地重要的供烃源岩一直是研究的热点。为了明确不同烃源岩的贡献及油气来源,通过对庆城地区长7段致密油特征进行分析,对原油进行精细划分,并对源岩有效性进行分析,进一步明确油源对应关系,研究表明,庆城地区长7段黑色页岩和暗色泥岩均对油气成藏有贡献,其中黑色页岩贡献最大,长73段暗色泥岩次之,长7_(2)和长7_(1)段暗色泥岩贡献较小;原油为低密度、中—低黏度和低凝固点的轻质油。根据生标物特征将原油划分为3类,A类原油具有低C_(30)重排藿烷/C_(29)藿烷、低C_(29)Ts/C_(29)藿烷、低Ts/Tm的特征,由黑色页岩贡献,主要分布于长7_(1)段;C类原油具有高C_(30)重排藿烷/C_(29)藿烷、高C_(29)Ts/C_(29)藿烷、高Ts/Tm的特征,主要由暗色泥岩贡献,数量较少且分布局限;B类油各项生标物参数均居中,为A、C类原油的混合,主要分布于长7_(2)段。由于黑色页岩生烃时间比暗色泥岩早,且原油黏度和密度更低,因此黑色页岩先生成低黏度A类原油易于向长7_(2)和长7_(1)段运移,而暗色泥岩后生成的C类原油主要近源富集与A类油混合分布于长7_(2)段,从而形成的A类油主要分布于长7_(1)段,B类油主要分布于长7_(2)段,而C类油分布局限的格局。这对下一步勘探开发及资源评价有重要意义。Objectives: The high-quality source rocks of the semi-deep lake—deep lake facies in the 7th Member of theYanchang Formation of Triassic (Chang-7 Member) in Ordos Basin are the important sources of oil and gas,including black shale and dark mudstone, which are the important source rocks of the basin. Most of the previousstudies have ignored the contribution of dark mudstone to oil and gas. Therefore, this paper analyzes thegeochemical characteristics of tight oil and source rock of Chang-7 oil formation in Qingcheng area, evaluates theeffectiveness of Chang-7 source rock, and analyzes the oil and gas source of Chang-7 oil formation, providingscientific basis for the study of oil and gas accumulation in the study area, and providing guidance for the next stepof oil and gas exploration.Methods: The tight sandstone reservoir was evaluated by using the whole rock X-ray diffraction, porosity andpermeability data. The physical properties of tight sandstone oil in the 7th Member of the Triassic YanchangFormation were analyzed by using the physical properties and group composition of crude oil. The maturity, parentmaterial source and environment of crude oil were analyzed according to the saturated hydrocarbon chromatography-mass spectrometry data. The lower limit of organic carbon of effective source rock was determined by using organicgeochemical data, combined with the geological data of oil and gas distribution in single well, the source anddistribution origin of oil and gas are comprehensively evaluated.Results: The research shows that the black shale and dark mudstone of Chang-7 Member in Qingcheng areaboth contribute to hydrocarbon accumulation, of which black shale has the largest contribution, followed by Chang-73 dark mudstone, and the dark mudstone of Chang-7_(2) and Chang-71 has the least contribution. The crude oil hasthe characteristics of low density, low viscosity and high saturation hydrocarbon. According to the characteristics ofbiomarkers, crude oil is divided into three types. Class A crude oil has t

关 键 词：致密油特征 烃源岩 油源对比 延长组7段 鄂尔多斯盆地 

分 类 号：P618.13[天文地球—矿床学]