二连盆地赛汉塔拉凹陷腾二段低熟油地球化学特征和油源对比  

Geochemical Characteristics and Source Correlation of Low-mature Oil from the Tengeer Formation(2nd Member)in the Saihantala Sag,Erlian Basin

作　　者：李杰豪 侯读杰[1,2] 曹兰柱 吴飘 赵喆 马潇潇 LI Jiehao;HOU Dujie;CAO Lanzhu;WU Piao;ZHAO Zhe;MA Xiaoxiao(School of Energy Resources,China University of Geosciences,Beijing 100083,China;Key Laboratory for Marine Reservoir Evolution and Hydrocarbon Abundance Mechanism,Ministry of Education,China University of Geosciences,Beijing 100083,China;Research Institute of Exploration and Development,PetroChina Huabei Oilfield Company,Renqiu,Hebei 062552,China)

机构地区：[1]中国地质大学(北京)能源学院,北京100083 [2]中国地质大学海相储层演化与油气富集机理教育部重点实验室,北京100083 [3]中国石油华北油田分公司勘探开发研究院,河北任丘062552

出　　处：《现代地质》2021年第2期315-325,共11页Geoscience

基　　金：国家自然科学基金项目(41472108,U1810201);中国石油天然气股份公司重大科技专项“华北油田持续有效稳产勘探开发关键技术研究与应用”(2017E-15);中央高校基本科研业务费专项资金项目(2020YJSMT02)。

摘　　要：赛汉塔拉凹陷位于二连盆地腾格尔坳陷西部,是二连盆地低熟油分布区。采用有机地球化学和生物标志物分析方法,对赛汉塔拉凹陷下白垩统腾二段低熟原油和油砂样品进行了地球化学特征和油源对比研究。赛汉塔拉凹陷腾二段低熟油具有饱和烃含量相对较低、非烃和沥青质含量相对较高的族组成特征,正构烷烃分布以前峰型为主,主峰碳为C_(21)或C_(23),Pr/Ph低(0.29~0.59),Pr/nC_(17)较低(0.29~0.58),Ph/nC_(18)较高(0.57~1.37),C_(29)甾烷20S/(20S+20R)为0.27~0.40、C_(29)甾烷ββ/(αα+ββ)为0.29~0.39,伽马蜡烷指数多为0.31~1.34,三环萜烷含量低,反映出原油生成于半咸水—咸水还原环境,生源以藻类输入为主。油源对比研究认为,赛汉塔拉凹陷腾二段低熟油有两种来源:一种是来自下伏腾一段烃源岩咸水环境成熟早期阶段生烃;另一种是来自洼槽中心低成熟的腾二段烃源岩自生自储。The Saihantala Sag is located in the western Tengeer depression of Erlian Basin,and contains low-mature oil in the Erlian Basin.The geochemical characteristics and oil source correlation of the low-mature crude oil and oil sandstone samples from the Lower Cretaceous Tengeer Formation(2nd member)in the Saihantala Sag were studied,by using organic geochemical and biomarker analyses.The low-mature oil from the Tengeer Formation(2nd member)is characterized by having relatively low content of saturated hydrocarbon,and relatively high content of non-hydrocarbon and asphaltene.The distribution of n-alkanes is of pre-peak type,and the main peak carbon is C_(21),C_(23).The Pr/Ph is low(0.29 to 0.58),Pr/nC_(17)is relatively low(0.29 to 0.59),Ph/nC_(18)is relatively high(0.57 to 1.37),and C_(29)20S/(20S+20R)of sterane is 0.27 to 0.40,C_(29)ββ/(αα+ββ)of sterane is 0.29 to 0.39,the gammacerane index is mainly 0.31 to 1.34,and the tricyclic terpane content is low,which reflects that the sedimentary environment of crude oil is a brackish-saline reducing one with mainly algae source input.According to the study of oil source correlation,there are two sources of the low-mature oils from the Tengeer Formation(2nd member)in the Saihantala Sag:(1)from the underlying Tengeer Formation(1st member)source rock and hydrocarbon generation at the early mature stage in salt-water environment;(2)from the self-generation and self-storage of the lowly-mature Tengeer Formation(2nd member)source rock in the depression center.

关 键 词：低熟油 地球化学特征 生物标志物 油源对比 赛汉塔拉凹陷 二连盆地 

分 类 号：TE122.1[石油与天然气工程—油气勘探]