塔里木盆地塔中北坡奥陶系微生物碳酸盐岩储层形成机制与评价  

Forming Mechanism of Ordovician Microbial Carbonate Reservoir in Northern Slope of Tazhong Uplift,Tarim Basin

作　　者：王玉伟 陈红汉[1] 曹自成 云露 Wang Yuwei;Chen Honghan;Cao Zicheng;Yun Lu(Faculty of Earth Resources,China University of Geosciences,Wuhan 430074,China;The North-west Oil Company,SINOPEC,Urumqi 830011, China)

机构地区：[1]中国地质大学资源学院,湖北武汉430074 [2]中国石油化工股份有限公司西北油田分公司,新疆乌鲁木齐830011

出　　处：《地球科学》2019年第2期559-571,共13页Earth Science

基　　金：国家重点基础研究发展计划973课题(No.2012CB214804);国家"十二五"重大科技专项(No.2008ZX05008-003-30)

摘　　要：微生物岩储层是当前的研究热点之一.通过对塔中北坡微生物岩样品的岩芯以及铸体薄片的观察,发现研究区域的微生物岩储层以裂缝-孔隙型储层为主.对其进行全直径孔渗性检测发现,微生物岩储层具有较好的天然气储集物性.通过对微生物岩的形成机制及特点的分析,结合应力敏感实验和成像测井资料,总结出微生物岩储集空间发育的优势因素.原生白云石的生成可以促进方解石的溶解,而塔中北坡微生物岩发生早成岩岩溶作用,部分地区叠加晚期深成热液改造,提高了储集物性;有机质含量较丰富不仅可以在埋藏成岩阶段生成有机酸造成溶蚀,还能够降低微生物岩的极限强度从而容易在构造作用下发生断裂形成裂缝,因此塔中北坡微生物岩储集空间主要以次生作用为主.通过岩石压缩系数的测定,得出微生物岩的抗压实能力一般,但藻屑骨架对藻孔的保护有利,抗压实能力最强的是受到热液作用而硅化的微生物岩,其次是白云石化微生物岩.The microbial carbonate reservoir is one of the hot research areas.The observation of microbialite’s core and casting thin sections of the northern slope of middle Tarim basin in our study shows that fracture-pore type reservoir dominates in the microbialites of study area.Though the porosity and permeability analysis of full diameter core,we found that the microbialites were good gas reservoirs.On the analysis of the formation mechanism and characteristics of microbialites,combined with stress sensitive experiment and imaging logging,we summarized the advantage factors of the forming reservoir space of microbialites,firstly,the generation of native dolomite can promote the dissolution of calcite.The microbialites of the study area experienced eogenetic karstification,and parts superposition late hypogenic karstification,improving the reservoir physical properties.Secondly,rich organic matter content not only caused dissolution by organic acid generated by microbialites in the burial diagenetic stage,but also reduced the ultimate strength of microbialites which could easy to form cracks under the tectonic movement.Therefore the reservoir space of microbialites in the northern slope of middle Tarim basin is mainly secondary role.Though the determination of rock compressibility,it is concluded that microbialites’compaction resistance is common,but algae crumbsskeleton is advantageous to the protection of the algal hole.The strongest ability to resist compaction is silicified microbialites,followed by dolomitization.

关 键 词：微生物岩储层 岩溶作用 裂缝 应力敏感 有机碳含量 岩石压缩 

分 类 号：P618.13[天文地球—矿床学]