克拉苏冲断带克深区带白垩系超深储集层成岩演化

发布时间：2018-02-09 03:33

本文关键词： 塔里木盆地库车坳陷克深区带白垩系巴什基奇克组超深储集层成岩环境　出处：《新疆石油地质》2017年01期 　论文类型：期刊论文

【摘要】：为探讨克拉苏冲断带克深区带白垩系巴什基奇克组超深储集层成岩机制与环境演化,应用岩石薄片、阴极发光、扫描电镜、流体包裹体测温及激光拉曼成分、能谱及主微量元素等分析手段,结合成岩标志矿物,刻画了超深层致密砂岩成岩演化特征。研究区白垩系超深储集层主要经历了碱性-弱酸性-碱性-酸性的流体演化过程,成岩流体与成岩矿物共生关系组合为:早期碱性流体阶段的铁染泥质包膜和泥晶碳酸盐矿物组合;表生酸性流体环境下的长石溶蚀和石英次生加大组合;回归碱性环境的石英溶蚀、硬石膏、白云石和长石次生加大组合;晚期酸性环境下的钾长石溶蚀、自生石英和丝发状伊利石组合。碱性胶结物占据大量孔隙及早期裂缝,降低了储集层的渗透能力,减孔量为10%~12%;晚期天然气充注携带的酸性流体沿粒缘缝、构造缝等优势运移通道对酸溶矿物进行溶蚀,形成大量溶蚀扩大孔及缝,改善了超深储集层物性,增孔量为2%~3%.因此,超深储集层有效储集空间受控于先碱性后酸性的成岩环境,碱性成岩产物为晚期酸性溶蚀提供物质基础,晚期酸性成岩环境对超深储集层物性的后期改善具有关键作用,酸性流体来自表生成岩阶段大气水淋滤和晚期天然气充注。
[Abstract]:In order to study the diagenetic mechanism and environmental evolution of the ultradeep reservoir of the Cretaceous Bashiki _ k formation in the Klassou thrust belt of the Ke deep zone, the thin rock sheet, cathodoluminescence, scanning electron microscope, fluid inclusion temperature measurement and laser Raman composition were used. The diagenetic evolution characteristics of ultra-deep dense sandstone are described by means of energy spectrum and principal trace elements, combined with diagenetic marker minerals. The ultradeep reservoir of Cretaceous in the study area mainly underwent the fluid evolution process of alkaline-weak acid-alkaline-acid. The symbiotic relationship between diagenetic fluid and diagenetic minerals is composed of iron muddy coating and mud-crystal carbonate mineral assemblage in the early alkaline fluid stage feldspar dissolution and quartz secondary augmentation in the environment of supergene acidic fluid. Quartz dissolution, anhydrite, dolomite and feldspar secondary augmentation in alkaline environment, potassium feldspar dissolution in late acidic environment, authigenic quartz and silky Illite assemblage. Alkaline cementation occupies a large number of pores and early fractures, The permeability of the reservoir is reduced by 10% and the pore volume is reduced to 12%. The acid fluid carried by natural gas filling in the late stage dissolves the acid-soluble minerals along the edge of the grain and the structural fractures, forming a large amount of dissolution and expanding pores and fractures. The physical properties of ultradeep reservoir are improved, and the increase of pore volume is 2% and 3%. Therefore, the effective reservoir space of ultra-deep reservoir is controlled by the diagenetic environment of alkalinity and then acidity, and the alkaline diagenetic products provide the material basis for the late acidic dissolution. The late acidic diagenetic environment plays a key role in the later improvement of the physical properties of the ultradeep reservoir. The acidic fluid comes from atmospheric water leaching during the epigenetic rock stage and late natural gas filling.
【作者单位】：西南石油大学油气藏地质及开发工程国家重点实验室;西南石油大学地球科学与技术学院;中国石油塔里木油田分公司油气工程研究院;中国石油塔里木油田分公司开发事业部;
【基金】：国家自然科学基金(51534006,51674211)
【分类号】：P618.13

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