鄂尔多斯盆地东南部长7段泥页岩黄铁矿成因及地质意义  

Genesis and geological significance of shale pyrite in Chang 7 Member of southeastern Ordos Basin

作　　者：刘钰晨 赵卫卫 高剑波[3,4] 霍志鹏 张佳琦 李慧 王嘉楠 LIU Yuchen;ZHAO Weiwei;GAO Jianbo;HUO Zhipeng;ZHANG Jiaqi;LI Hui;WANG Jianan(School of Earth Science and Engineering,Xi′an Shiyou University,Xi′an 710065,China;Shaanxi Key Laboratory of Petroleum Accumulation Geology,Xi′an Shiyou University,Xi′an 710065,China;School of Resources and Materials,Northeastern University at Qinhuangdao,Qinhuangdao 066004,China;National Engineering Research Center of Offshore Oil and Gas Exploration,Beijing 100028,China)

机构地区：[1]西安石油大学地球科学与工程学院,陕西西安710065 [2]西安石油大学陕西省油气成藏地质学重点实验室,陕西西安710065 [3]东北大学秦皇岛分校资源与材料学院,河北秦皇岛066004 [4]海洋油气勘探国家工程研究中心,北京100028

出　　处：《断块油气田》2024年第6期978-984,共7页Fault-Block Oil & Gas Field

基　　金：国家科技重大专项课题“陆相页岩储气机理与储层精细描述研究”(2017ZX05039-002)。

摘　　要：鄂尔多斯盆地页岩油气资源丰富,延长组长7段作为全盆地主力烃源岩,富有机质泥页岩发育且厚度稳定、连续性好,同时伴生大量黄铁矿。前人对长7段泥页岩沉积环境、地球化学特征、生排烃机理等做了大量工作,但针对黄铁矿形成原因及反应机理研究相对较少。因此,文中结合全岩矿物体积分数和镜下照片等分析化验资料,系统研究长7段泥页岩黄铁矿形态特征、成因机制、沉积水体环境、与有机质催化、富集关系及对储层改善、破坏作用,综合探明黄铁矿地质意义。结果表明:长7段泥页岩黄铁矿形成于硫化-缺氧和贫氧环境下,形成了自形晶和草莓状2种形态黄铁矿,同时经历细菌硫酸盐还原(BSR)和热化学硫酸盐还原(TSR)2种还原作用,对促进有机质生烃、改善储层具有重要作用。Ordos Basin is rich in shale oil and gas resources.As the main source rock of the whole basin,Chang 7 Member of Yanchang Formation develops organic-rich shale with stable thickness and good continuity,and is associated with a large amount of pyrite.The predecessors have done a lot of work on sedimentary environment,geochemical characteristics and hydrocarbon generation mechanism of shale in Chang 7 Member,but there are relatively few studies on the formation reasons and reaction mechanism of pyrite.Therefore,combined with the analysis and laboratory data of whole rock mineral volume fraction and microscopic photos,the morphological characteristics,genetic mechanism,sedimentary water environment,the relationship with organic matter catalysis and enrichment and improvement and destruction effect on reservoir of shale pyrite in Chang 7 Member are systematically studied,and the geological significance of pyrite is comprehensively explored.The results show that the shale pyrite in Chang 7 Member is formed in a sulfidation-hypoxia and oxygen-poor environment,forming two forms of pyrite:automorphic crystal and strawberry-shaped pyrite.At the same time,it undergoes two reductions of bacterial sulfate reduction(BSR)and thermochemical sulfate reduction(TSR),which plays an important role in promoting hydrocarbon generation of organic matter and improving reservoir.

关 键 词：黄铁矿成因 BSR与TSR还原作用 有机质生烃 储层改善 长7段 

分 类 号：TE122[石油与天然气工程—油气勘探]