羌塘盆地上三叠统—下侏罗统海相页岩油特征及发现意义  

Characteristics and discovery significance of the Upper Triassic-Lower Jurassic marine shale oil in Qiangtang Basin,NW China

作　　者：沈安江 付小东 张建勇 魏学斌[3] 胡安平 王剑 熊绍云 付修根 谢渊[5] 刘思琪 李茜 王鑫 贺训云 乔占峰 郑剑锋 段军茂 SHEN Anjiang;FU Xiaodong;ZHANG Jianyong;WEI Xuebin;HU Anping;WANG Jian;XIONG Shaoyun;FU Xiugen;XIE Yuan;LIU Siqi;LI Xi;WANG Xin;HE Xunyun;QIAO Zhanfeng;ZHENG Jianfeng;DUAN Junmao(Key Laboratory of Carbonate Reservoirs,CNPC,Hangzhou 310023,China;PetroChina Hangzhou Institute of Petroleum Geology,Hangzhou 310023,China;Research Institute of Exploration and Development,PetroChina Qinghai Oilfield Company,Dunhuang 736202,China;Qiangtang Basin Research Institute,Southwest Petroleum University,Chengdu 610500,China;Civil-military Integration Center of Geological Survey,China Geological Survey,Chengdu 610036,China)

机构地区：[1]中国石油天然气集团有限公司碳酸盐岩储集层重点实验室,杭州310023 [2]中国石油杭州地质研究院,杭州310023 [3]中国石油青海油田公司勘探开发研究院,青海敦煌736202 [4]西南石油大学羌塘盆地研究院,成都610500 [5]中国地质调查局军民融合地质调查中心,成都610036

出　　处：《石油勘探与开发》2023年第5期962-974,共13页Petroleum Exploration and Development

基　　金：中国石油“十四五”前瞻性基础性重大科技项目(2021DJ08);国家自然科学基金专项项目(42241203)。

摘　　要：羌塘盆地油气地质调查和浅钻在中生界海相地层发现了页岩油显示。基于露头、岩心样品系统分析测试,研究了海相页岩沉积发育条件与特征,评价了地球化学与储集特征。研究了中生界海相页岩油发育特征,取得以下认识:①羌塘盆地发育下侏罗统曲色组和上三叠统巴贡组两套海相富有机质泥页岩,主要由纹层状页岩夹块状泥岩构成。曲色组纹层状富有机质泥页岩位于该地层下部,厚度为50~75 m,主要分布于南羌塘和北羌塘中西部。巴贡组纹层状富有机质泥页岩位于地层中部,厚度为250~350 m,在南北羌塘均有分布。②两套纹层状富有机质泥页岩页理发育,同时发育多种类型的微孔隙和微裂缝,脆性矿物含量平均70%,可压裂性强,孔隙度均值5.89%,储集物性好,达到中等—好的页岩油储集层标准。③曲色组富有机质泥页岩为Ⅱ1和Ⅱ2型有机质,TOC均值8.34%,氯仿沥青“A”含量均值0.66%,残余生烃潜量(S1+S2)均值29.93 mg/g,R_(o)值0.9%~1.3%,达到优质烃源岩标准。巴贡组富有机质泥页岩为混合型有机质,TOC值为0.65%~3.10%,R_(o)值1.17%~1.59%,达到中等烃源岩标准。④4口井深50~250 m浅钻分别在巴贡组下部井深50~90 m井段和曲色组中部井深30~75 m井段的有机质泥页岩中见油花,原油饱和烃含量高,结合露头和浅钻样品分析测试确认巴贡组和曲色组发现海相页岩油,其中,巴贡组好的页岩油段位于剖面下部18—20层,S0+S1值大于1 mg/g的泥页岩厚206.7 m,S0+S1值最高1.92 mg/g,均值1.81 mg/g;曲色组好的页岩油段位于剖面下部4—8层,S0+S1值大于1 mg/g的泥页岩厚58.8 m,S0+S1值最高6.46 mg/g,均值2.23 mg/g。Mesozoic marine shale oil was found in the Qiangtang Basin by a large number of hydrocarbon geological surveys and shallow drilling sampling.Based on systematic observation and experimental analysis of outcrop and core samples,the deposition and development conditions and characteristics of marine shale are revealed,the geochemical and reservoir characteristics of marine shale are evaluated,and the layers of marine shale oil in the Mesozoic are determined.The following geological understandings are obtained.First,there are two sets of marine organic-rich shales,the Lower Jurassic Quse Formation and the Upper Triassic Bagong Formation,in the Qiangtang Basin.They are mainly composed of laminated shale with massive mudstone.The laminated organic-rich shale of the Quse Formation is located in the lower part of the stratum,with a thickness of 50-75 m,and mainly distributed in southern Qiangtang Basin and the central-west of northern Qiangtang Basin.The laminated organic-rich shale of the Bagong Formation is located in the middle of the stratum,with a thickness of 250-350 m,and distributed in both northern and southern Qiangtang Basin.Second,the two sets of laminated organic-rich shales develop foliation,and various types of micropores and microfractures.The average content of brittle minerals is 70%,implying a high fracturability.The average porosity is 5.89%,indicating good reservoir physical properties to the level of moderate-good shale oil reservoirs.Third,the organic-rich shale of the Quse Formation contains organic matters of types II1 and II2,with the average TOC of 8.34%,the average content of chloroform bitumen'A'of 0.66%,the average residual hydrocarbon generation potential(S1+S2)of 29.93 mg/g,and the R_(o) value of 0.9%-1.3%,meeting the standard of high-quality source rock.The organic-rich shale of the Bagong Formation contains mixed organic matters,with the TOC of 0.65%-3.10%and the R_(o) value of 1.17%-1.59%,meeting the standard of moderate source rock.Fourth,four shallow wells(depth of 50-250 m)with oil

关 键 词：海相页岩油 上三叠统巴贡组 下侏罗统曲色组 毕洛错地区 石油沟地区 羌塘盆地 

分 类 号：TE122[石油与天然气工程—油气勘探]