西非Rio Muni盆地上白垩统小型深水扇沉积特征及勘探潜力

Depositional characteristics and exploration potential of the late Cretaceous small deep-water fan in Rio Muni Basin,West Africa

西非沿岸除发育第三系大型深水扇体系外,在上白垩统时期还发育多个小型深水扇体系,至今还未引起足够重视。以Rio Muni盆地为例,在分析盆地宏观物源体系及切谷特征的基础上,选取盆地典型油气勘探区块,对上白垩统小型深水扇沉积特征、演化模式进行详细解剖,建立其沉积模式,明确西非上白垩统深水扇体系的特点及发育控制因素。在与第三系大型深水扇对比的基础上,探讨其成藏特征及勘探潜力。分析认为,Rio Muni盆地发育白垩系小型线物源深水扇体系,深水扇规模是影响其勘探层系、储层厚度及物性、圈闭类型、储量规模的主要因素,需在勘探研究中引起重视。

Besides the large deep - water fan system, some small deep - water fan systems were developed in the West Africa, so far which have not been paid enough attention. In this paper, the small late Cretaceous deep - water fan in Rio Muni Basin was taken as an example. Based on the analysis of distribution of provenance system and main canyon, deposi- tional type, distribution characteristics, and facies model, control factors of small late Cretaceous deep - water fan system have been studied. Compared with the large tertiary deep - water fan in West Africa, it was considered that the scale of deep - water fan is the main affecting factor on exploration layer, reservoir thickness and property, type of trap, and reserve scale, which need to be paid attention.