宽扎盆地油气地质特征

安哥拉宽扎盆地是典型被动大陆边缘盆地,完整经历了前裂谷阶段、裂谷阶段、过渡阶段及漂移阶段等4个构造演化阶段,形成了盐下、盐间和盐上3套沉积层序,并各自形成含油气系统。在对宽扎盆地构造演化、沉积特征及油气成藏条件进行分析后认为:宽扎盆地盐下、盐间和盐上3套沉积层序的油气成藏主控因素分别为拉伸断陷、盐隆起及盐构造运动;宽扎盆地盐下有利勘探区为盆地东部白垩系地堑构造区,盐间有利勘探区为盆地中东部盐隆发育部位,盐上有利勘探区为盆地东部古近系和新近系地堑发育部位;宽扎盆地今后勘探工作重点应放在盆地东部白垩系地堑构造区的盐下碳酸盐岩储层目标。

PETROLEUM GEOLOGY IN KWANZA BASIN

The Kwanza Basin of Angola is a typical passive continental marginal basin with successive developing phases of pre-rifting, syn-rifting, transitional and post-rifting （drifting）. In the basin filled the pre-salt sequence, the intrasalt sequence and the post-salt sequence successsively, and each sequence had its own petroleum system. Based on the analysis of the tectonic evolution, depositional characteristics and basic conditions for reservoir formation in the Kwanza Basin, it is suggested that the main factors controlling reservoir are the extensional depression in pre-salt sequence, the salt-mo- tivated uplifting in intra-salt sequence and salt movement in post-salt sequence. The favorable exploration areas are the Cretaceous graben in the eastern part of the basin for the pre-salt sequence, the salt upheaval in the middle eastern part of the basin for the intra-salt sequence, and the Tertiary graben in the eastern part of the basin for the post-salt sequence. The future exploration target is the carbonate rock reservoirs of pre-salt sequence in the east of Kwanza Basin.