准噶尔盆地东道海子凹陷及周缘中二叠统平地泉组烃源岩地球化学特征  

Geochemical characteristics of the Middle Permian Pingdiquan Formation source rocks in the Dongdaohaizi Sag and its periphery, Junggar Basin

作　　者：秦志军 尹晟宇[3] 操应长 周川闽[4] 李开开[3] 龚德瑜[4] Zhijun QIN;Shengyu YIN;Yingchang CAO;Chuanmin ZHOU;Kaikai LI;Deyu GONG(China University of Petroleum(East China),Qingdao 266071,China;Research Institute of Petroleum Exploration and Development,Xinjiang Oilfield Company,PetroChina,Karamay 834000,China;School of Energy College,China University of Geosciences(Beijing),Beijing 100083,China;Research Institute of Petroleum Exploration and Development,PetroChina,Beijing 100083,China)

机构地区：[1]中国石油大学(华东),山东青岛266071 [2]中国石油新疆油田公司勘探开发研究院,新疆克拉玛依834000 [3]中国地质大学(北京)能源学院,北京100083 [4]中国石油勘探开发研究院,北京100083

出　　处：《天然气地球科学》2024年第11期1910-1922,共13页Natural Gas Geoscience

基　　金：国家自然科学基金项目(编号:42272188);中国石油前瞻性基础性技术攻关项目(编号:2021DJ0206,2022DJ0507);中国石油直属院所基础科学研究和战略储备技术研究基金(编号:2020D-5008-04)联合资助。

摘　　要：准噶尔盆地已发现的油气主要位于中央坳陷周缘和坳陷内的隆起区。东道海子凹陷在中央坳陷的众多次级凹陷中勘探程度最低,目前对其主力烃源岩层系——中二叠统平地泉组的研究程度也很低。基于岩心薄片观察、总有机碳、干酪根碳同位素组成、岩石热解和生物标志物分析,系统评价了该套烃源岩的生烃潜力和形成环境,并与邻区——阜康凹陷中二叠统芦草沟组烃源岩进行了对比。结果表明,东道海子凹陷平地泉组烃源岩岩性在深凹区以深灰色—灰黑色灰质泥岩、粉砂质泥岩和泥岩为主,在浅湖区则以灰色—深灰色泥岩和粉砂质泥岩为主,为一套深湖—半深湖相沉积。该套烃源岩以Ⅱ型干酪根为主,整体属于中等—好烃源岩级别。晚二叠世,该套烃源岩进入生烃门限,现今已整体进入生干气阶段。该套烃源岩沉积于偏还原的咸水环境,以细菌和藻类等水生生物输入为主,陆源高等植物输入为辅。东道海子凹陷及周缘平地泉组烃源岩与阜康凹陷及周缘芦草沟组烃源岩整体面貌相近。目前,围绕后者已取得一系列勘探突破,预示着东道海子凹陷及周缘平地泉组含油气系统同样具备良好的勘探潜力。研究结果进一步夯实了准噶尔盆地二叠系含油气系统的资源潜力,也为东道海子凹陷及周缘的油气勘探提供了重要参考。The oil and gas discovered in the Junggar Basin are mainly distributed in the periphery of the Central Depression and the uplift area within the depression.The exploration degree of Dongdaohaizi Sag is the lowest among the many secondary sags in the Central Depression,and the research degree of its main source rock,the Middle Permian Pingdiquan Formation,is also very low.Based on core thin section observation,total organic carbon,kerogen carbon isotope composition,Rock-Eval pyrolysis and biomarker analysis,the hydrocarbon-generating potential and formation environment of the Pingdiquan Formation source rocks were systematically evaluated,and compared with the Middle Permian Lucaogou Formation source rocks in the neighboring Fukang Sag.The results show that the lithology of the Pingdiquan Formation source rocks in the Dongdaohaizi Sag is primarily composed of deep gray-black gray mudstone,silty mudstone and mudstone in the profundal zone,and mainly composed of gray-dark gray mudstone and silty mudstone in the sublittoral zone,which is a set of deep to semi-deep lacustrine sediments.The Pingdiquan Formation source rocks mainly comprise of typeⅡkerogen,and belong to medium to good source rock.In the Late Permian,this set of source rocks entered the threshold of hydrocarbon generation,and now the whole has entered the stage of dry gas generation.The Pingdiquan Formation source rocks were deposited in a brackish environment with main input of aquatic organisms such as bacteria and algae,supplemented by the input of terrigenous higher plants.The Pingdiquan Formation source rocks in the Dongdaohaizi Sag share similar geochemical characteristics with the Middle Permian Lucaougou Formation source rocks in the Fukang Sag.At present,a series of exploration breakthroughs have been made around the latter,implying that the Pingdiquan Formation petroleum system in the Dongdaohaizi Sag may also has good exploration potential.The research results further consolidate the resource potential of the Permian petroleum system in the

关 键 词：准噶尔盆地 东道海子凹陷 中二叠统 平地泉组 深湖—半深湖沉积 生烃潜力 形成环境 

分 类 号：TE122.113[石油与天然气工程—油气勘探]