国外含油气盆地硅质岩储集层主要类型及勘探开发特点

Types and characteristics of chert reservoirs in oversea petroliferous basins

结合近年来国外硅质岩油气藏勘探、开发实际情况,简要介绍硅质岩的成因、组成和分类,进而讨论硅质岩油气藏的圈闭分类、储集特性、岩石物理特征及钻井、完井和生产过程中所遇到的问题。硅质岩是指由生物作用、化学作用、生物化学作用和火山作用形成的富含SiO2的岩石,岩性致密、坚硬、易碎。硅质岩油气藏圈闭可分为裂缝型、古风化壳型、热液型、自生自储型、水动力型和侧向隔挡型6种类型。硅质岩储集层非均质性极强,孔渗性受岩相、泥质含量和孔隙性质等诸多因素控制。研究表明硅质岩适于作为优异的储集岩类,在良好的生、储、盖组合条件下可以形成油气藏,是重要的岩性油气藏勘探目标。

Combining with the actual exploration and production of oil and gas in cherts in foreign countries,this paper describes the origin,composition and classification of cherts and discusses the trap type,reservoir nature,petrophysical features of chert reservoirs and problems met in drilling,completion and production processes.Cherts are silica-rich rocks formed by biological,chemical,biochemical,and volcanic processes.They are tight,hard and brittle.Traps of chert oil and gas reservoirs can be divided into six types,fractured,weathering crust,hydrothermal,self-generation and self-storage,hydraulic,and lateral barrier.Chert reservoirs are heterogeneous and their porosity and permeability are controlled by rock facies,muddy content,and pore nature,among other factors.Study shows that cherts are excellent reservoir rock and can form oil and gas reservoirs if there is a good association of source,reservoir and seal.They are important target for lithological reservoirs of oil and gas.