西非油气富集的关键地质因素及勘探战略部署建议

非洲具有比较丰富的油气资源。西非海岸发育了15个含油气盆地,可勘探面积达331×104km2。西非海岸盆地发育3套主要的烃源岩、4套主要的储层,存在4个重要的勘探领域,既有成熟领域,也有新领域。盐岩和巨厚泥岩的发育及强烈活动对油气成藏具有重要影响。已经在整个西非海岸15个盆地发现了2095个油气田(藏),待发现资源量还很大,预计达1169×108bbl油当量。近几年来,在西非中部含盐盆地群、尼日尔三角洲盆地和科特迪瓦盆地深水区发现了多个巨型、大型油气田,掀起了西非深水勘探热潮。从勘探潜力和油气富集程度来看,西非是中国石油公司在非洲最重要的油气勘探战略基地。综合对比考虑各盆地(群)基本石油地质条件、勘探程度、勘探潜力等地质因素和非地质因素(如投资环境、政治经济、与中国关系、安全等),建议中国石油公司重点关注走滑拉分盆地群深水区(重点在科特迪瓦盆地)、中部含盐盆地群深水区(重点在刚果扇盆地和宽扎盆地)和尼日尔三角洲盆地;加强对西南非盆地群(重点在西南非海岸盆地)、北部含盐盆地群(重点在塞拉利昂—利比里亚盆地和塞内加尔盆地)油气成藏条件及勘探潜力研究。如果上述盆地有一定的勘探潜力,则可作为中国石油公司在西非的后备战场。

Key Geological Factors of Hydrocarbon Enrichment in West Africa and Suggestions for Strategic Exploration Planning

Africa has rich oil and gas resources,15 petroleum basins developed in the coast of West Africa,with the exploration area being as high as 3.31 million square kilometers.Three sets of main source rocks and four sets of main reservoirs developed in the basins of the coast,and there are four important exploration domains here,including mature and new ones.The development and violent activity of salt rock and extremely thick mud rock exert great effect on hydrocarbon reservoir formation.Now 2095 oil and gas fields(reservoirs) have been discovered in 15 basins here,and there are still huge resources to be discovered,which are expected to reach 116.9 billion bbl oil equivalent.In recent years,many large oil and gas fields have been discovered in the salt basin group in middle of West Africa,the Niger Delta Basin,and deep water area of Cte d’Ivoire Basin,upholding a vigorous campaign for deep water exploration in West Africa.Viewing from exploration potential and hydrocarbon enrichment degree,West Africa is the most important strategic basin of oil and gas exploration for Chinese oil companies in West Africa.Considering the basic petroleum geologic conditions,exploration degree,exploration potential and other non-geologic factors(such as investment environment,politics and economy,relationship with China,and safety,etc.) based on comparative analysis,it is suggested that Chinese oil companies focus on the deep water area of strike-slip pullapart basin group in middle of West Africa(mainly in Congo Fan Basin and Kwanza Basin),and Niger Delta Basin,and strengthen the study on hydrocarbon reservoir formation conditions and exploration potential in Southwest Africa basin group(mainly the basins in the coast of Southwest Africa),northern salt basin group(mainly the Sierra Leone-Liberia Basin and Senegal Basin).The basins mentioned above could be the reserve battleground of Chinese oil companies in West Africa,if they have certain exploration potential.