吐哈盆地十三间房地区侏罗系水西沟群有机质聚集环境及富集机理  

Organic matter aggregation environment and enrichment mechanism of the Jurassic Shuixigou Group in the Shisanjianfang area of the Tuha Basin

作　　者：李立果 杨曙光 田继军 李鑫[1] 王大兴 许润泽 马骥 Li Liguo;Yang Shuguang;Tian Jijun;Li Xin;Wang Daxing;Xu Runze;Ma Ji(College of Geology and Mining Engineering,Xinjiang University,Ürümqi 830017;CBD Research and Development Center of Xinjiang Coal Geological Bureau,Ürümqi 830091;Key Laboratory of Tectonics and Petroleum Resources Ministry of Education,China University of Geosciences(Wuhan),Wuhan 430074;School of Resources,China University of Geosciences(Wuhan),Wuhan 430074;Exploration and Development Research Institute,Shengli Oilfield Company,SINOPEC,Dongying,Shandong 257015)

机构地区：[1]新疆大学地质与矿业工程学院,乌鲁木齐830017 [2]新疆维吾尔自治区煤田地质局煤层气研究开发中心,乌鲁木齐830091 [3]中国地质大学(武汉)构造与油气资源教育部重点实验室,武汉430074 [4]中国地质大学(武汉)资源学院,武汉430074 [5]中国石化胜利油田分公司勘探开发研究院,山东东营257015

出　　处：《地质科学》2025年第1期44-61,共18页Chinese Journal of Geology(Scientia Geologica Sinica)

基　　金：国家自然科学基金项目“新疆急倾斜低煤阶储层火烧区水文地质特征及其对煤层气富集成藏的控制”(编号:U1903303);新疆维吾尔自治区天山英才计划项目(编号:2023TSYCLJ0005,2022TSYCCX0043)资助。

摘　　要：十三间房地区水西沟群作为吐哈盆地侏罗系下一步油气勘探开发主力层,但其有机质聚集古环境与富集机理尚不明确。通过X全岩衍射、总有机碳(TOC)测定、主微量元素测试与生物标志化合物等分析手段对吐哈盆地十三间房地区水西沟群淡水有机质聚集环境进行了分析,并探讨了有机质富集的控制因素及机理。结果显示:十三间房地区水西沟群淡水浅湖发育以灰色和灰黑色为主的泥岩与碳质源岩,可见黄铁矿与水平层理。水西沟群有机质为混合输入,有机质类型以Ⅱ_(2)和Ⅲ型为主,有机质整体位于成熟阶段。J_(1)s和J_(1)b组TOC均值分别为3.67%、4.29%,多为混合输入;J_(2)x出现最大湖泛面,TOC均值(2.74%)最低,有机质类型以Ⅲ型为主。古环境指标表明十三间房地区水西沟群发育温带季风气候下的淡水浅湖,古均气温低于15℃,水体为分层一般的厌氧环境。J_(1)s沉积时期得益于南北双向陆源供给,P元素富集,水体还原性略强,有机质丰度相对高;J_(1)b古气温较低,水体固碳能力强,陆源与水生生物源混合输入;水陆交汇受限、有机质消耗加快与水体氧化性加强抑制了J_(2)x时期有机质富集,陆源输入占比较大。古环境指标与TOC值耦合关系表明,古气候、陆源碎屑输入与古生产力为有机质富集主控因素,厌氧环境利于有机质保存。温润条件下的陆相淡水浅湖,有机质易富集于水陆交汇程度好的浅水环境,即湖湾沼泽等低能滞水环境,这与强调高盐、水深对有机质高富集作用下的海相、咸水及淡水深湖环境有所不同。The Shuixigou Group in the Shisanjianfang area is the next main layer for oil and gas exploration and development in the Jurassic of Tuha Basin,but the paleoenvironment and enrichment mechanism of its organic matter aggregation are still unclear.The environment of freshwater organic matter aggregation in the Shuixigou Group in the Shisanjianfang area of Tuha Basin was analyzed by X-diffraction analysis,total organic carbon(TOC)analysis,principal trace element testing and biomarker compounds,and the controlling factors and mechanisms of organic matter enrichment were explored.The results showed that the freshwater shallow lakes of the Shuixigou Group in the Shisanjianfang area developed gray and gray-black dominated mudstones with carbonaceous source rocks,and pyrite and horizontal laminations are visible.The organic matter of the Shuixigou Group was a mixed input,the organic matter type was dominated by Type Ⅱ_(2) and Ⅲ,and the organic matter as a whole was located in the mature stage.The mean J_(1)s and J_(1)b TOC values were 3.67% and 4.29%,respectively,with mostly mixed inputs.The largest lake floodplain surface occurred in J_(2)x,which had the lowest mean TOC value(2.74%),and the organic matter type was dominated by Type Ⅲ.Paleoenvironmental indicators show that the Shuixigou Group in the Shisanjianfang area developed a freshwater shallow lake in a temperate monsoon climate,with paleo-mean temperatures lower than 15°C,and the water body was a stratified and generally anaerobic environment.The J_(1)s depositional period benefited from a bi-directional north-south land-source supply,P enrichment,slightly more reducing waters,and relatively high organic matter abundance.J_(1)b paleotemperatures were low,water bodies had a high capacity for carbon sequestration,and terrestrial sources were mixed with water autochthonous sources of input.Limited land-water interface,accelerated organic matter depletion and enhanced water oxidation inhibited organic matter enrichment during the J_(2)x period,with land-based

关 键 词：低能滞水 有机质富集 温润淡水浅湖 水西沟群 十三间房地区 

分 类 号：P618.13[天文地球—矿床学]