下刚果盆地北部碳酸盐岩层序地层分析

Sequence stratigraphy of the carbonate rock in northern Lower Congo Basin

以层序地层学理论为基础,利用地震及钻井资料,对西非刚果(布)海上下刚果盆地北部海域白垩系Lower Sendji组海相碳酸盐岩层系进行层序地层与沉积储层精细研究。研究认为,Lower Sendji组时期,研究区发育浅海碳酸盐岩缓坡台地混合沉积体系,该体系以颗粒灰岩的颗粒滩微相沉积为主。自下向上将Lower Sendji组划分为SQ1～SQ4共4个三级层序。下伏盐岩与碳酸盐岩盐筏块体发生重力滑动,造成局部地势微弱起伏,同时控制其上碳酸盐岩储层的发育和展布。

The sequence stratigraphy and sedimentary reservoirs in the marine carbonate rocks of Cretaceous lower Sendji formation,the north of offshore Lower Congo Basin,Congo(Brazzaville),West Africa,have been studied by using seismic and drilling data.The study shows that shallow offshore carbonate ramp platform sedimentation system had developed in the lower Sendji formation and was dominated by grainstone of grain bank microfacies.Four third-order sequences are divided from below for the lower Sendji formation,namely SQ1～SQ4.Gravity sliding in the underlying salt rock and carbonate salt raft had led to slight relief locally,meanwhile controlled the development and distribution of overlying carbonate reservoirs.