鄂尔多斯盆地安塞地区延长组长9段原油地球化学特征与油源对比  

Oil Geochemical Characteristics and Oil-Source Correlation of Chang 9 Member of Yanchang Formation in Ansai Area,Ordos Basin

作　　者：惠瑞瑞 刘妍 张志升[1] 张治东[1] 李斌[1] 郭爱华[1] Hui Ruirui;Liu Yan;Zhang Zhisheng;Zhang Zhidong;Li Bin;Guo Aihua(Xingzichuan Oil Production Plant of Yanchang Oil Field Co.,Ltd.,Yan’an 717400,Shaanxi,China;School of Science,Chang’an University,Xi’an 710064,China)

机构地区：[1]延长油田股份有限公司杏子川采油厂,陕西延安717400 [2]长安大学理学院,西安710064

出　　处：《吉林大学学报（地球科学版）》2024年第5期1468-1481,共14页Journal of Jilin University：Earth Science Edition

基　　金：国家自然科学基金项目(41772118);陕西省自然科学基础研究计划项目(2023-JC-QN-0289)。

摘　　要：鄂尔多斯盆地安塞地区延长组长9段打出高产原油,勘探前景良好。本文采用有机地球化学测试分析与生物标志化合物分析方法,对安塞地区长9段原油和长7段与长9段烃源岩地球化学特征进行研究,并开展油源对比分析。结果表明:长9段原油Pr/Ph值平均为1.86,原油形成于弱还原-弱氧化环境,ααα-20R C_(27)-C_(28)-C_(29)甾烷分布呈反“L”型,指示陆相高等植物为主的混合来源,C_(29)甾烷20S/(20S+20R)为0.48~0.51,C_(29)甾烷ββ/(αα+ββ)为0.52~0.53,表明原油均已成熟。长7段烃源岩有机质类型以Ⅱ-Ⅲ型及Ⅲ型为主,沉积于弱还原-弱氧化环境,普遍进入生油高峰期,规则甾烷相对质量分数以C_(29)>C_(28)>C_(27)为主,表明与陆相高等植物输入密切相关;长9段烃源岩有机质类型主要为Ⅱ-Ⅲ型及Ⅲ型,沉积于弱还原-弱氧化环境,均进入生油高峰期,规则甾烷C_(29)相对质量分数最高,表明与陆相高等植物成分密切相关。油源对比结果表明,安塞地区长9段原油为长7段和长9段烃源岩混合来源。The Chang 9 Member of Ansai area in Ordos basin has produced high-yield crude oil,which has good exploration prospects.The geochemical characteristics of Chang 9 crude oil and Chang 7 and Chang 9 source rocks in Ansai area were studied by using organic geochemical and biomarker analysis methods,and then oil-source correlation analysis was carried out.The results show that the average Pr/Ph value of Chang 9 crude oil is 1.86,formed in a weak reduction-weak oxidation environment.The ααα-20R C_(27)-C_(28)-C_(29)sterane configuration is inverted“L”type,indicating a mixed source dominated by terrestrial higher plants.C 29 sterane 20S/(20S+20R)is 0.48-0.51 and C_(29)sterane ββ/(αα+ββ)is 0.52-0.53,indicating that the crude oil is mature.The organic matter types of Chang 7 source rocks are mainly Ⅱ-Ⅲ and Ⅲ,deposited in a weak reduction-weak oxidation environment,and generally entered the peak oil generation period.The mass fraction of regular steranes is dominated by C_(29)>C_(28)>C_(27),indicating that they are closely related to the input of terrestrial higher plants.The organic matter types in Chang 9 are mainly Ⅱ-Ⅲ and Ⅲ,which was deposited in a weak reduction-weak oxidation environment,and has generally entered the peak oil generation period.The content of C_(29)in regular steranes is the highest,indicating that it is closely related to the terrestrial higher plant composition.According to the oil-source correlation,the crude oil of Chang 9 Member in Ansai area is a mixed source of Chang 7 and Chang 9 source rocks.

关 键 词：油源对比 地球化学 生物标志化合物 延长组 鄂尔多斯盆地 

分 类 号：P618.13[天文地球—矿床学]