鄂中地区下奥陶统碳酸盐岩成岩作用及孔隙演化

THE DIAGENESlS AND POROSITY EVOLUTlON OF LOWER ORDOVICIAN CARBONATE ROCKS IN CENTRAL HUBEI

本文根据岩石学特征、沉积构造、生物化石等标志将鄂中地区下奥陶统碳酸盐岩沉积划分为五种不同的相带，其中以开阔台地相最为发育。并采用阴极发光、氧碳同位素、混合染色等手段，详细研究了该区碳酸盐岩成岩作用类型、成岩序列和孔隙演化特征。认为胶结、溶解、压溶作用和白云石化作用是控制该区碳酸盐岩储层的主要因素，聚集期孔隙形成于深埋藏成岩环境。

The sequence of lower Ordovician in central Hubci is bominated by carbonate rocks,it can be devided into five principal facies zones:restricated platform facies,open platform facies,platform border shoal facies,basin margin facies,and neritic shelf facies, of which open pIatformfacies is dominated. Based on the observation of a large number of sections,using athodoluminescent petrogfa-phy,stable isotopes of, carbon and oxygen,composite colouring,the paper studies in detail the dia-genesis,diagenetic sequences,and porosity evolution of lower Ordovician carbonate in centraIHubei.The study shows that cementation, solution, dolomitization,compaction and pressure-solu-tion were the principal factors in controlling the reservoir properties of lower Ordovician carbon-ate rocks in this area,and that the pores of accumulation stage were directly selated to the solutionand pressure-solution in deep burial diagenetic environment.