鄂尔多斯盆地南部奥陶系马家沟组五段白云岩埋藏溶蚀作用研究  

Dissolution characteristics of deep-buried dolostone in the Member 5 of Ordovician Majiagou Formation in southern Ordos Basin

作　　者：雷涵 黄文辉[1,2,3] 伊硕[1,2,3] 王雅婷 Lei Han;Huang Wen-Hui;Yi Shuo;Wang Ya-Ting(School of Energy Resources,China University of Geosciences(Beijing),Beijing 100083,China;Key Laboratory for Marine Reservoir Evolution and Hydrocarbon Abundance Mechanism,China University of Geosciences(Beijing),Beijing 100083,China;Beijing Key Laboratory of Unconventional National Gas Geology Evaluation and Development Engineering,China University of Geosciences(Beijing),Beijing 100083,China)

机构地区：[1]中国地质大学(北京)能源学院,北京100083 [2]中国地质大学(北京)海相储层演化与油气富集机理教育部重点实验室,北京100083 [3]中国地质大学(北京)非常规天然气地质评价及开发工程北京市重点实验室,北京100083

出　　处：《古地理学报》2020年第6期1041-1052,共12页Journal of Palaeogeography：Chinese Edition

基　　金：国家自然科学基金重点项目(编号:41472136)资助。

摘　　要：为了解鄂尔多斯盆地南部奥陶系马家沟组五段白云岩储集层不同类型埋藏溶蚀作用的作用过程及其对物性的影响,依据岩心和镜下观察,结合包裹体温度、微量元素和稀土元素数据分析,将马五段埋藏溶蚀作用分为有机酸流体埋藏溶蚀作用、热液埋藏溶蚀作用和TSR作用,其中有机酸流体溶蚀作用会导致层状溶孔、沥青薄膜和圆环的形成,而热液溶蚀作用会导致无组构无选择性溶孔、块状和脉状黄铁矿充填、热液矿物(组合)充填的出现。研究区马五段埋藏溶蚀作用发生模式为:(1)中侏罗世直罗期,低温热液埋藏溶蚀作用发生;(2)中侏罗世末期,伴随第1次烃类充注,有机酸流体埋藏溶蚀作用开始;(3)早白垩世东胜期,中—高温热液埋藏溶蚀作用发生;(4)早白垩世末期,伴随着第2次更大规模的烃类注入,TSR作用发生。对比发现,有机酸和热液溶蚀作用均对储集层有建设性作用,但热液比有机酸流体可以更有效地提高储集层物性。The different types of deep-buried dissolution process in the Member 5 of Ordovician Majiagou Formation in the southern Ordos Basin and its influence on the reservoir properties are studied in this paper.It shows that three types of mechanisms include organic acid fluid,hydrothermal fluid and TSR are identified through studies of core observation,thin section analysis,inclusion temperature,trace elements and rare earth elements.It is found that the dissolution of organic acid fluid causes the stratified dissolution pores,film-like asphaltene and ring-like asphaltene,while hydrothermal fluid causes the non-selective dissolution pores without petrofabric,veins of pyrites,massive pyrites and the association of hypothermal minerals.Four occurrence models of dissolution include,(1)the deep-buried dissolution of low-temperature hydrothermal fluid occurs in Zhiluo Period of Middle Jurassic;(2)the deep-buried dissolution of organic acid fluid started from the late Middle Jurassic followed by the first hydrocarbon injection;(3)the deep-buried dissolution of middle-high temperature hydrothermal fluid occurred in the Dongsheng Period of Early Cretaceous;(4)TSR occurred at the end of Early Cretaceous with the second larger hydrocarbon injection.Both organic acid fluid and hydrothermal fluid can improve the porosity and permeability of reservoir,but the hydrothermal fluid is more effective than that of organic acid fluid.

关 键 词：鄂尔多斯盆地 埋藏溶蚀作用 热液作用 有机酸流体 TSR作用 

分 类 号：P618.13[天文地球—矿床学]