鄂尔多斯盆地长7段页岩半开放体系生排烃模拟实验研究  

Semi-closed heat simulation experiment of a Chang 7 Member shale in the Ordos Basin

作　　者：刘显阳[1,2] 吴凯[1,2] 孔庆芬[1,2] 刘大永[3,4] 施健飞 彭平安 LIU Xianyang;WU Kai;KONG Qingfen;LIU Dayong;SHI Jianfei;PENG Ping’an(Research Institute of Exploration and Development,PetroChina Changqing Oilfield Company,Xi’an 710018,Shaanxi,China;National Engineering Laboratory of Low-permeability Oil&Gas Exploration and Development,Xi’an 710018,Shaanxi,China;State Key Laboratory of Organic Geochemistry,Guangzhou Institute of Geochemistry,Chinese Academy of Sciences,Guangzhou 510640,Guangdong,China;CAS Center for Excellence in Deep Earth Science,Guangzhou 510640,Guangdong,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]低渗透油气田勘探开发国家工程实验室,陕西西安710018 [3]中国科学院广州地球化学研究所,有机地球化学国家重点实验室,广东广州510640 [4]中国科学院深地科学卓越创新中心,广东广州510640

出　　处：《地球化学》2022年第4期434-440,共7页Geochimica

基　　金：有机地球化学国家重点实验室自主课题(SKLOG2020-1);长庆油田分公司技术服务项目(技2019-141)联合资助。

摘　　要：鄂尔多斯盆地上三叠统延长组长7段富有机质页岩是这一区域页岩油、致密油的主要烃源岩,其生排烃特征是石油勘探开发的关键问题。采取鄂尔多斯盆地西南缘三叠系延长组长7段低熟(R_(o)=0.55%)页岩岩心样品(TOC=3.59%),设置不同模拟温度(300~570℃),开展原岩岩心柱状样品的半封闭体系生排烃模拟实验,获得了不同成熟度梯度的页岩模拟样品残余及排出烃类。利用低熟煤样标定各模拟温度点的成熟度(0.60%<R_(o)<3.95%),模拟前后的页岩样品均进行质量称重、总有机碳(TOC)分析、岩石热解(Rock-Eval)分析、溶剂抽提及排烃定量分析。结果表明:随模拟实验温度增加,页岩的质量损失率及排水率逐渐增加。页岩生油过程主要发生在400℃以前,残留烃(二氯甲烷–甲醇混合溶剂抽提物)、残留可动烃(正已烷抽提物)及排出液态组分(液态烃和沥青质)高峰均出现在340~360℃(0.78<R_(o)<0.92%)之间,并且在420℃以前达到排出液态组分的极值,最高可达255.58 mg/g(每克TOC中的生成量)。在半封闭体系下,页岩可排出液态组分总量最高可占到原始样品生烃潜量的44%。Triassic Chang 7 Member(Chang 7)shale is the predominant source rock of shale oil and tight oil in the Ordos Basin,and evaluation of the hydrocarbon generation and expulsion capacity of the source rocks have great significance.Plugs of low maturated Chang 7 shale in the southwest margin of the Ordos Basin were adopted for semi-closed heat simulation experiments between 300 and 570℃.A series of post-simulation residues at different temperatures were acquired for weighing,geochemical analysis,and solvent extraction.Furthermore,the expelled hydrocarbons were collected for quantitative analysis.The results showed that weight loss and water expulsion ratios increased with increasing temperature.Oil generation and expulsion were completed before 400℃,and the quantity of residue,mobile,and expelled hydrocarbons reached their maximum values at 340 to 360℃(0.78%<R_(o)<0.92%).The total weight of expelled hydrocarbon and asphaltene reached its maximum value of 255.58 mg/g before 420℃.These results indicated that approximately 44%of the initial oil potential might be expelled out of the shale as liquid hydrocarbon and bitumens.

关 键 词：长7段 页岩 生排烃 半封闭体系 模拟实验 

分 类 号：P599[天文地球—地球化学] P618.12[天文地球—地质学]