加蓬海岸盆地油气成藏组合特征及有利目标优选

Characteristics and favorable target optimization of hydrocarbon plays in the Gabon Coastal Basin

在加蓬海岸盆地最新油气田相关数据与油气地质资料基础上,以储层为核心将盆地划分了盐上、盐下两类共6个油气成藏组合,其中位于盐下有贝利阿斯阶砂岩成藏组合、阿普特阶砂岩成藏组合,盐下油气成藏组合特征为:陆相储层、盐岩上覆遮挡封盖、断裂带运移;而位于盐上有阿尔布阶—赛诺曼阶砂岩成藏组合、马斯特里赫特阶碎屑岩成藏组合、康尼亚克阶—坎潘阶浊积岩成藏组合、始新统—渐新统河道砂岩成藏组合,盐上油气成藏组合特征为:海相储层、盐构造控藏、盐运动沟通源储。以蒙特卡洛模拟为计算方法,以成藏组合为单元进行油气资源评价,计算出加蓬海岸盆地未来30年待发现资源量为6895×10~6bbl,其中石油资源量为5893×10~6bbl,天然气资源量为6005×10~9ft3;凝析油资源量为34×10~6bbl。结合加蓬海岸盆地成藏组合特征分析与资源评价结果,认为阿普特阶砂岩成藏组合为最有利勘探区。

Based on the latest oil and gas field information and petroleum geological data of the Gabon Coastal Basin, it is divided into 6 hydrocarbon plays of two categories（i.e., suprasalt and subsalt） with reservoirs as the core. Among them, Berriasian sandstone play and Aptian sandstone play are located below salt rocks. These subsalt plays are characterized by continental reservoir, salt rock as the overlying barrier and sealing bed and fracture belt as the migration pathway. Albian-Cenomanian sandstone play, Maastrichtian clastic play, Coniacian-Campanian turbidite play and Eocene-Oligocene channel sandstone play are located above salt rocks. And these suprasalt plays are characterized by marine reservoir, salt structure controlling reservoir and salt movement connecting source rock with reservoir. Then, oil and gas resources were evaluated with the play as the unit by means of Monte Carlo method. And according to the calculation results, the resources to be discovered in the Gabon Costal Basin in the following 30 years are 6895×106 bbl, including oil resources of 5893×106 bbl, natural gas resources of 6005×109 ft3 and condensate oil resources of 34×106 bbl. It is indicated from the analysis on the characteristics of plays in the Gabon Coastal Basin and the resource evaluation results that Aptian sandstone play is the most favorable exploration target.