准噶尔盆地芦草沟组致密油系统油源对比与成藏非均质性研究  

Oil-source correlation and accumulation heterogeneity of tight oils in the Middle Permian Lucaogou Formation,Junggar Basin

作　　者：王俞策 曹剑[1] 陶柯宇 李二庭[2] 向宝力[2] 施春华[1] Wang Yuce;Cao Jian;Tao Keyu;Li Erting;Xiang Baoli;Shi Chunhua(School of Earth Sciences and Engineering,Nanjing University,Nanjing,210023,China;Research Institute of Experiment and Testing,PetroChina Xinjiang Oilfield Company,Karamay,834000,China)

机构地区：[1]南京大学地球科学与工程学院,南京210023 [2]中国石油新疆油田分公司,克拉玛依834000

出　　处：《南京大学学报（自然科学版）》2020年第3期322-337,共16页Journal of Nanjing University（Natural Science）

基　　金：国家自然科学基金(41830425,41802145);中国石油重大科技专项(2017E⁃0401)。

摘　　要：致密油成藏的非均质性是当前致密油研究的热点与难点,为进一步深化对其的理解,以准噶尔盆地吉木萨尔凹陷中二叠统芦草沟组为例,开展了一个实例研究.结果表明,芦草沟组垂向上总体可分为上、下甜点体及其所夹的中部泥岩段.烃源岩研究发现,芦草沟组整段发育优质烃源岩,并以上下甜点体更好,主要生物母质为水生藻类,干酪根类型主要是Ⅱ型,成熟演化.油源对比研究发现,芦草沟组"下甜点体"自生自储、近源聚集.相比而言,"上甜点体"除了也有近源聚集特征外,同时跨层为上覆上二叠统梧桐沟组提供油源.而中部泥岩段所生原油主要运移至"上甜点体"成藏.故芦草沟组的成藏从下到上依次为近源聚集、纵向运移、近源聚集以及纵向运移,表现出强烈的非均质性,这可能是陆相致密油聚集的普遍特征,在勘探开发中需加以关注,从页岩油-致密油-常规油全含油气系统的角度考虑.这些认识可应用于区域下一步油气勘探部署中.The heterogeneity of accumulation is highlighted and challenging in the study of tight oil systems.To improve the understanding of ths issue,this study conductes a case study in the middle Permian Lucaogou Formation of the Jimusar sag,Junggar basin.Results show that the Lucaogou Formation can be divided into three sections,i.e.,the Upper sweet spots,the Lower sweet spots,and the middle section mudstones intervening the two sweet spots.Orgnic rich source rock are developed not only in the two sweet spots but also in the entire middle section mudstones.Kerogen is primarily TypeⅡwith the contribution of auqtic alage.Thermal maturity is moderate.Oil-source correlation reveals the source rocks and reservoirs have similar geochemical characteristics in the lower sweet spots,reflecting a proximal hydrocarbon accumulation pattern(near-source accumulation).In contrast,the hydrocarbons generated in the upper sweet spots are not only preserved in the upper sweet spots internally but also migrated to the overlying upper Permian Wutonggou Formation reservoirs.Oils generated in the middle section mudstones also migrated to the high-quality reservoirs in the upper sweet spots.As such,the tight oil accumulation is complex in the study area.From base to top,the accumulation patterns in the Lucaogou Formation were near-source accumulation,vertical migration and accumulation,near-source accumulation,and vertical migration and accumulation,thereby showing strong heterogeneities.Our data suggest that these processes and patterns might be typical of tight oil accumulations universally,especiall in lacustrine systems.The exploration and study should be extended to the totoal petroleum systems including shale oil,tight oil and conventiaonl oil.In addition,the results will provide significant guidance for future exploration and exploitation in the region.

关 键 词：致密油 页岩油 成藏非均质性 全含油气系统 咸化湖盆 芦草沟组 准噶尔盆地 

分 类 号：P59[天文地球—地球化学]