摘要
准噶尔盆地吉木萨尔凹陷芦草沟组发育凝灰物质,凝灰物质在页岩油形成过程中具有的重要作用,其发育层段也是页岩油分布最好的层段,凝灰物质的分布及与有机质生烃关系的研究对于吉木萨尔页岩油油气成藏规律的认识和深入研究具有重要意义。本文通过对吉木萨尔芦草沟组烃源岩精细评价及沉积环境分析,与烃类活动具有成因关系的成岩矿物解剖,探讨了形成优质页岩油源岩的控制因素和生烃机制。烃源岩定性评价结果表明,泥晶白云岩是吉木萨尔凹陷芦草沟组主要生油岩,烃源岩有机质丰度高,有机质类型以Ⅰ型和Ⅱ1型为主,生烃潜力较好,Ro值分布在0.6%~1.1%,C29αααS/(S+R)值范围在0.3~0.5,显示烃源岩处于成熟阶段;芦草沟组烃源岩中规则甾烷C27、C28、C29分布为C27<C28<C29,结合微观分析认为其生烃母质以藻类和超微生物为主,Ts/Tm值较低,分布在0.05~0.18,具有高含量的β-胡萝卜烷,反映其母质处于半咸水的弱氧化—弱还原的沉积环境之中,而这一时期火山活动提供的凝灰物质对烃源岩的生烃环境及热演化进程都有重要影响,热演化突然增大的层段与有机质成熟的"甜点段"的分布深度一致。凝灰物质与含超微生物及藻类的泥晶白云岩的混合是导致生烃和早期生烃的重要原因,两者混合的不均一性导致页岩油分布与成熟度的不均匀性。
Objectives:Tuff was developed in the Lucaogou Formation in the Jimsar Sag,Junggar Basin.And the tuff matter plays an important role in the formation of shale oil,and its development interval is also the best oil-bearing interval of shale oil.Therefore,the study of distribution of tuff matter and its relationship with the hydrocarbon generation of organic matter is of great significance for the understanding of oil and gas accumulation rules of the Jimsar shale oil.Methods:Based on evaluation source rocks and analysis its sedimentary environment,combining study of diagenetic minerals that have a genetic relationship with hydrocarbon activities,the controlling factors and hydrocarbon generation mechanism of the formation of high-quality shale oil source rocks of the Lucaogou Formation in the Jimsar Sag were discussed.Results:Qualitative analysis of source rocks indicate that muddy dolostone is main source rock of Lucaogou Formation in Jimsar Sag.The source rock has high abundance of organic matter and good hydrocarbon generation potential,type of organic matter is mainly type I and type II1.The source rock is inmature stage,with Ro value is between 0.6%and 1.1%,and C29αααS/(S+R)ratio is between 0.3 and 0.5.Distribution of regular sterane C27,C28 and C29 in source rocks of Lucaogou Formation is C27<C28<C29.Combined with microscopic analysis,it is believed its hydrocarbon forming parent material is dominated by algae and supermicrobe.Low Ts/Tm ratio which is between 0.05 and 0.18,and high content ofβ-carotene reflects its parent material is in weak oxidation to weak reduction deposition environment of brackish water.And tuff provided by volcanic activity during this period has an important influence on hydrocarbon generation environment and thermal evolution process of the source rocks.The layer of sudden increase in thermal evolution is consistent with depth of distribution of mature"dessert segment"of organic matter.Conclusions:Mixing of tuff materials with muddy dolostone which containing supermicrobes and alg
作者
王剑
李二庭
陈俊
米巨磊
马聪
雷海艳
谢礼科
WANG Jian;LI Erting;CHEN Jun;MI Julei;MA Cong;LEI Haiyan;XIE Like(Research Institute of Experiment and Detection,PetroChina Xinjiang Oilfield Company,Karamay,Xinjiang,834000;Xinjiang Key Laboratory of Shale Oil Exploration and Development,Karamay,Xinjiang,834000)
出处
《地质论评》
CAS
CSCD
北大核心
2020年第3期755-764,共10页
Geological Review
基金
新疆维吾尔自治区重点实验室开放课题资助项目(编号:2017D04023)的成果。
关键词
芦草沟组
烃源岩
生烃机制
凝灰物质
准噶尔盆地
Lucaogou Formation
source rock
hydrocarbon generation mechanism
tuff
Jimsar Sag
