南加蓬次盆盐下油气分布规律及勘探方向

Hydrocarbon distribution regularity and exploration trend of pre-salt section in South Gabon sub-basin

 饶勇 阳怀忠 郭志峰

 中海油研究总院海外评价中心，北京 100028

 Overseas Evaluation Center, CNOOC Research Institute, Beijing 100028, China

 南加蓬次盆属于典型的被动大陆边缘含盐盆地，盆地经历了3期构造￣沉积演化阶段，盐下裂谷期纽康姆阶基辛达（Kissenda）组和巴列姆阶梅拉尼亚（Melania）组2套优质成熟的烃源岩、多套储￣盖组合以及一系列构造圈闭为盐下油气聚集成藏提供了有利的石油地质条件。通过分析各成藏组合特征认为，受构造圈闭和储层发育控制，盐下油气具有“内油外气，上多下少”的分布规律。在此基础上初步探讨了南加蓬次盆盐下勘探方向，即外坳陷带主要寻找上组合大型构造气藏为主，中部隆起带主要寻找断阶带上组合登泰尔（Dentale）构造油藏，内坳陷带主要寻找中￣下组合优质储层构造油藏。

 South Gabon sub-basin is a typical Atlantic passive margin salt basin, which has experienced three tectonic and sedimentary evolution stages. Two sets of high-quality mature source rocks of the Neocomian Kissenda Formation and the Barremian Melania Formation, accompanied with multiple sets of reservoir-cap assemblage as well as a series of structural traps provided favorable geological conditions for hydrocarbon accumulation of pre-salt section in rifting stage. According to the analysis of each play, the pre-salt oil and gas show the distribution regularity of "inner oil and outer gas, upper more and lower less" is controlled by the structural tarps and reservoirs. Based on the above statement, preliminary discussions of potential exploration trend indicates that the outer depression mainly focuses on the upper play for finding the large structural gas reservoirs, the central uplift belt mainly focuses on the upper play for finding the structural oil reservoirs of Dentale in the fault terrace belt, and the inner depression mainly focuses on the middle-lower play for finding the structural oil reservoirs of high-quality reservoir.

10.6056/dkyqt201804007