西非毛塞几比盆地油气成藏差异性分析
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摘要
从毛塞几比盆地构造演化特征分析入手,明确中大西洋的演化控制了毛塞几比盆地的形成,盆地经历了裂陷期、过渡期和漂移期3个演化阶段。受过渡期和漂移期构造和沉积差异演化的控制,盆地划分为南次盆和北次盆,南次盆具有"宽陆架、陡陆坡"、北次盆具有"窄陆架、缓陆坡"的结构特征。漂移期发育Cenomanian—Turonian和Aptian—Albian 2套海相烃源岩,其热演化程度具有"北高南低"的分布特征。盆地发育多种有利沉积储层类型,盆地结构控制了沉积储层的差异分布,南次盆以陆架边缘三角洲砂岩和浊积扇砂岩储层为主,北次盆以浊积水道和浊积扇砂岩储层为主。盆地主要发育3种典型的油气成藏模式,北次盆主要发育"自生自储、近源成藏"和"下生上储、盐相关断裂运移"2种成藏模式,而南次盆主要发育"旁生侧储、断裂+不整合面运移"和"自生自储、近源成藏"2种成藏模式。
Tectonic study suggests that the evolution of Mid-Atlantic controls the formation of Senegal Basin. Once it was formed, the basin has experienced three stages of evolution: rifting stage, transitional stage and drifting stage. Under the Control of differentiation of tectonic and sedimentation in the transitional and drifting stages, the basin was separated into two parts, the southern sub-basin and the northern sub-basin. The southern sub-basin is characterized by a "wide shelf and steep slope", while the north sub-basin is opposite and characterized by a "narrow shelf and gentle slope". Cenomanian-Turonian and Aptian-Albian marine source rocks are well developed in the drifting stage, and the thermal evolution of source rock is in a pattern of "high north and low south". There are a variety of favorable sedimentary reservoirs in the basin. The structure of the basin controls the distribution of sediments. The southern sub-basin is dominated by continental shelf deltaic sandstone and turbidite fan sandstone, whereas the northern sub-basin is mainly composed of turbidite channels and turbidite fan sandstones. Three types of hydrocarbon accumulations are found available in the basin. The northern sub-basin is dominated by the accumulations of "self-generated and self-accumulated near-source hydrocarbon" and the type of "later accumulation of early generated hydrocarbon through salt-related fault migration", while southern sub-basin is characterized by oil and gas "generated in-situ and accumulated laterally with faults and unconformities as migration paths" and the type of "self-generated and accumulated hydrocarbon in near-source storages".
Tectonic study suggests that the evolution of Mid-Atlantic controls the formation of Senegal Basin. Once it was formed, the basin has experienced three stages of evolution: rifting stage, transitional stage and drifting stage. Under the Control of differentiation of tectonic and sedimentation in the transitional and drifting stages, the basin was separated into two parts, the southern sub-basin and the northern sub-basin. The southern sub-basin is characterized by a "wide shelf and steep slope", while the north sub-basin is opposite and characterized by a "narrow shelf and gentle slope". Cenomanian-Turonian and Aptian-Albian marine source rocks are well developed in the drifting stage, and the thermal evolution of source rock is in a pattern of "high north and low south". There are a variety of favorable sedimentary reservoirs in the basin. The structure of the basin controls the distribution of sediments. The southern sub-basin is dominated by continental shelf deltaic sandstone and turbidite fan sandstone, whereas the northern sub-basin is mainly composed of turbidite channels and turbidite fan sandstones. Three types of hydrocarbon accumulations are found available in the basin. The northern sub-basin is dominated by the accumulations of "self-generated and self-accumulated near-source hydrocarbon" and the type of "later accumulation of early generated hydrocarbon through salt-related fault migration", while southern sub-basin is characterized by oil and gas "generated in-situ and accumulated laterally with faults and unconformities as migration paths" and the type of "self-generated and accumulated hydrocarbon in near-source storages".
引文
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[10] C&C Reserviors.Chinguetti Field Mauritanian Salt Basin,Mauritania,field evaluation report[EB].2005:1-26.
[2] 徐汉梁,单玄龙,高璇,等.西非塞内加尔盆地重油成藏条件及富集规律[J].科学技术与工程,2014,14(16):211-215.
[3] 邓荣敬,邓运华,于水,等.西非海岸盆地群油气勘探成果及勘探潜力分析[J].海洋石油,2008,28(3):11-19.
[4] 熊利平,刘延莉,霍红.西非海岸南、北两段主要含油气盆地油气成藏特征对比[J].石油与天然气地质,2010,31(4):410-419.
[5] 刘剑平,潘校华,马君,等.赤道西非科特迪瓦-加纳转换边缘油气勘探方向[J].石油勘探与开发,2010,37(1):43-50.
[6] 温志新,徐洪,王兆明,等.被动大陆边缘盆地分类及其油气分布规律[J].石油勘探与开发,2016,43(5):678-688.
[7] 王大鹏,殷进垠,田纳新,等.塞内加尔盆地成藏组合划分与资源潜力评价[J].现代地质,2017,31(6):1201-1213.
[8] Davison I.Central Atlantic margin basins of North West Africa:geology and hydrocarbon potential(Morocco to Guinea)[J].Journal of African Earth Sciences,2005,43(1/3):254-274.
[9] Debenay J P,Pages J,Guillou J J.Transformation of subtropical river into a hyperhaline estuary,the Casamance River (Senegal) -paleogeographical implications[J].Palaeogeography,Palaeoclimatology,Palaeoecology,1994,107(1/2):103-119.
[10] C&C Reserviors.Chinguetti Field Mauritanian Salt Basin,Mauritania,field evaluation report[EB].2005:1-26.