中国天然气碳酸盐岩储层形成的成岩模式  

A Diagenetic Model on the Formation of Carbonate Gas Reserviors in China

作　　者：朱莲芳[1] 

机构地区：[1]中国科学院兰州地质研究所

出　　处：《沉积学报》1995年第2期140-149,共10页Acta Sedimentologica Sinica

基　　金："八五"国家重点科技攻关项目

摘　　要：碳酸盐岩储层形成和成岩环境密切相关，本文根据我国实际情况将成岩环境划分为海洋、埋藏和表生三种环境。碳酸盐岩储气层的形成主要为白云岩化作用和岩溶作用。对次生孔隙的储集空间成因，提出了白云岩化形成白云岩溶孔的机制。岩溶作用是在地壳抬升的表生环境作用下，碳酸盐岩发生溶解、溶蚀、坍塌等作用的总和。提出了碳酸盐岩储层形成的成岩模式，明确指出在成岩过程中有三次储集层形成，每次伟层的形成，都可形成气田。并论证了储集层形成的地质条件、变化因素、形成时间以及对储层条件评价。The formation of carbonate gas reserviors has a close relation with the diagenetic environment, which controls the development of primary and secondary porosities in carbonate reservoirs. In terms of burial depth and features of water medium, the diagenetic environment can be divided into three types, i. e., marine,burial and epidiagenetic environments, of which the most favorable porosity zone is shallow flat, beach and reef environments and meteoric vadose zone in epidiagenetic environment.The mechanisms responsible for the formation of carbonate reserviors are dolomitization and karstification. The fact that the excellent pore--type resrviors are commonly present in dolomite has been confirmed in many gas fields in China. The strata in which the giant gas fields formed are Sinian, Carboniferous in Sichun Basin and Ordovician in Ordos and Tarim Basin. The dolomitization developed in different stages can all produce excellent intercrystal and intergranular porosities as well as secondary porosity. The gas field reseryiors relevant to the karstification in China account for 83% in the total numbers of the proved gas fields. Theintensity and depth of karstification vary directly with the exposure time. Accordingly, the time for the slight karstification is approximately 5--20 Ma, the intermediate 40 Ma and the extensive 100-- 200 Ma, of which the first and the second contain the best porosity. Therefore, when assessing reservoir quality, this fator should be taken into consideration.The experiment results of comparision study on dissolubility and corrosion between different types of carbonate rocks indicate that limestone is greater than dolomitite in dissolublity, but inversrely in physical destruction quantity leading to the frequent observation of dolomitite breccia and solution cave in limestone in geohistory. The pure limestone appears to have the large dissolubility and rapid dissolution rate, and the average dissolubility of limestone is larger than that of dolomitite by 36%. In addition to composition, th

关 键 词：天然气 碳酸盐岩 储集层 成岩环境 成岩模式 

分 类 号：P618.130.2[天文地球—矿床学]