中国克拉通盆地演化与碳酸盐岩—蒸发岩层序油气系统

Evolution of Cratonic Basins and Carbonate-Evaporite Sedimentary Sequence Hydrocarbon Systems in China

中国克拉通盆地,如塔里木、鄂尔多斯和四川盆地,下伏有裂谷或坳拉谷,说明克拉通盆地随超大陆裂解而发育,其后,克拉通盆地随超大陆拼合而上叠前陆盆地。前期热沉降环境诱发良好烃源岩形成;中期发育完整碳酸盐—蒸发岩旋回,构成有利储层;晚期挤压环境形成盖层和上叠层,形成旋回式油气系统。在古隆起上碳酸盐台地构成有利的储集带,而发育在斜坡和半深海盆地中的浊流沉积提供有效烃源岩,形成相变式油气系统。碳酸盐岩储集层结构类型由3种主要因素所控制:沉积作用、海平面升降作用与构造作用,由此形成孔隙、溶洞和裂缝3种基本原型。可进一步构成:孔隙—溶洞型;溶洞—裂缝型和裂缝—孔隙型。

Cratonic basins in China, such as the Tarim, the Ordos and the Sichuan basins, were developed on the former riffs or aulacogens following super-continent posed by foreland basins, following supercontinent reservoir rocks developed in carbonate-evaporite cy break-up. Afterwards, cratonic basins were superimamalgamation. Source rocks developed in the early stages; cles in the middle stage during periods of subsidence; and seal and overburden rocks formed in the late stage under contractional regimes, which produced a hydrocarbon system based on the cratonic cycle model. When carbonate platforms developed on paleo-uplifts, they started producing favorable reservoir rocks. Meanwhile, turbidity currents developed in the slope and semi-abyssal basin areas, providing source rocks for the hydrocarbon system under a facies change model. The three carbonate reservoir textural types are the pore-type, cavernous type, and three major factors： sedimentation, relative sea level change fissure type. They are controlled by the following and tectonism. In practice the carbonate reservoir types are usually found in combination rather than singly, examples being the pore-cavern, karst cavern-fissure, or fissure-pore types.