摘要
吉木萨尔凹陷芦草沟组是陆相盆地页岩油勘探开发的主力层位,但其古环境信息与有机质富集机理尚不明确。为了深入研究二叠系芦草沟组的沉积古环境,在岩心和薄片观察的基础上,通过X射线荧光光谱(XRF)和电感耦合等离子质谱(ICP-MS)对J10025井26块烃源岩样品进行主微量元素测试,并结合GC-MS生物标志化合物数据与典型沉积构造反映芦草沟组古环境特征。古气候指数C值、Sr/Cu、Sr/Ba、V/Cr、Pr/Ph、P、Co元素等地化指标表明,芦草沟组整体上为干旱—半干旱的咸化湖泊沉积环境,沉积时期水体较深,且为贫氧—缺氧的状态。其中,芦草沟组上段整体为半干旱气候、微咸水环境,还原性相对较弱,水体较深,生产力较高,但环境波动较大;芦草沟组下段环境比较稳定,气候极度干旱,盐度较高,还原性相对较强,水体较浅,生产力较低。古环境指标与TOC含量的相关性分析结果显示,有机质的保存条件以及稀释速率对芦草沟组有机质富集的影响比较有限,而初级生产力大小是芦草沟组有机质富集的主控因素。
The Lucaogou Formation in the Jimsar Sag is the main target layer of shale oil exploration and development in continental basins.However,its paleo-environmental information and organic matter enrichment mechanism still need to be determined.In order to investigate the paleo-environment of the Permian Lucaogou Formation,based on core and thin section observation,we carried out major and trace element analyses on 26 source rocks from Well J10025 by using X-ray fluorescence spectroscopy(XRF)and inductively coupled plasma mass spectrometry(ICP-MS).This analysis,combined with GC-MS biomarker data and typical sedimentary structures,reflects the paleo-environmental characteristics of the Luchaogou Formation.Geochemical indicators such as C-value,Sr/Ba,V/Cr,Pr/Ph,P,and Co show that the Lucaogou Formation was generally developed in a saline lake environment under an arid to semi-arid climate,with relatively deep water during deposition and hypoxic to anoxic conditions.The upper member was deposited in a semi-arid,brackish lake with weak reducibility,deep water body,and high productivity.In contrast,the lower member was deposited in an extremely dry,highly saline,and strongly reductive shallow lake with low productivity.The paleo-environment of the upper member fluctuated wildly,while that of the lower member was relatively stable.The correlation analyses between paleo-environmental indicators and TOC show that the preservation conditions and dilution rate of organic matter have limited influence on organic matter enrichment of the Lucaogou Formation.At the same time,the primary productivity is the main controlling factor.
作者
刘金
王剑
谭静强
崔海骕
刘淼
郑雨
宋雪琪
元强
LIU Jin;WANG Jian;TAN Jingqiang;CUI Haisu;LIU Miao;ZHENG Yu;SONG Xueqi;YUAN Qiang(Key Laboratory of Shale Oil Exploration and Development,Karamay 834000,Xinjiang,China;Research Institute of Experiment and Testing,Xinjiang Oilfield Company,PetroChina,Karamay 834000,Xinjiang,China;School of Geosciences and Info-Physics Engineering,Central South University,Changsha 410083,Hunan,China;School of Civil Engineering,Central South University,Changsha 410075,Hunan,China)
出处
《地质力学学报》
CSCD
北大核心
2023年第5期631-647,共17页
Journal of Geomechanics
基金
国家自然科学基金项目(41872151)
中德科学中心合作交流项目(M0588)
湖南省重点研发计划项目(2022WK2004)
湖南省自然资源厅重大项目(2022-05)。
关键词
吉木萨尔
芦草沟组
页岩油
沉积古环境
有机质富集
Jimsar
the Lucaogou Formation
shale oil
sedimentary paleo-environment
organic matter enrichment
作者简介
第一作者:刘金(1989-),男,硕士,工程师,从事微束、微区分析及非常规油气地质研究。E-mail:602393581@qq.com;通讯作者:谭静强(1983-),男,博士,教授,从事非常规油气地质评价研究。E-mail:tanjingqiang@csu.edu.cn。
