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南大西洋是全球深水油气勘探热点地区,深水油气资源丰富。基于国际商业数据库油气田数据统计与滨岸盆地成盆规律,分析表明:南大西洋深水油气平面上主要分布于六大盆地内、走向上以中段富含盐岩盆地为主、横向上伸展带发现居多、纵向上储集在过渡期碳酸盐岩和漂移期浊积岩内,可以利用共轭特征类比进行被动陆缘深水油气勘探。结合盆地资料与区域地质认识,梳理了南大西洋深水油气聚集规律:1深水油气形成于含高塑性体伸展与挤压和不含高塑性体开阔环境三大构造背景;2含有裂谷期湖相泥岩、漂移早期和漂移中晚期海相页岩3套有效烃源岩;3发育盐上三角洲与浊积碎屑岩、盐下潟湖相碳酸盐岩2套优质储层;4拥有厚层盐岩和海相页岩2种类型区域性盖层;5富含构造—地层、构造等多种成因圈闭类型;6深水油气经断裂短距离运移,紧邻生烃中心聚集;7形成上白垩统、下白垩统和新生界3套重要深水成藏组合;8深水油气晚期成藏,以构造—地层、构造油气藏类型为主。通过建立不同类型盆地深水油气成藏模式,指出不同构造段深水勘探重点方向:北段上白垩统近岸叠覆型深水扇、赤道段古近系—新近系斜坡水道及深水逆冲带前缘、中段伸展带盐上浊积岩和底辟—逆冲带盐下碳酸盐岩、南段上白垩统与断块相关斜坡水道。
The South Atlantic is a hot spot for deepwater oil and gas exploration in the world. Deepwater oil and gas resources are abundant. Based on the statistics of oil and gas fields in the International Business Database and the basin-forming laws of the coastal basin, the analysis shows that the deep-water oil and gas in the South Atlantic is mainly distributed in the six major basins, with the middle part being mainly salt-rich basins and the lateral stretching belts mostly found , Longitudinally accumulated in the transitional carbonate and drift stage turbidite, the conjugate feature analogy can be used for passive continental margin deepwater oil and gas exploration. Combining with basin data and regional geological understanding, the rule of oil and gas accumulation in the deep ocean in the South Atlantic is summarized: (1) deep-water hydrocarbons formed in three tectonic settings with extensional and extrusion of high-plastic bodies and open environment without high plastic bodies; (2) 3 sets of effective source rocks of mudstone, early drifting and mid-late marine shale; 3 development of two sets of high-quality reservoirs on salt upper delta and turbidite clastic rocks and salt lacustrine carbonate facies; 4 a thick layer of salt Rock and marine shale; 5 rich trap-type of tectonic-stratigraphy and tectonics; 6 deep-water oil and gas migrated by fault short-distance, closely adjacent to hydrocarbon generation center; 7 formed of upper chalk The Lower Cretaceous and the Cenozoic three major deep-water reservoir assemblages, and the deep-water hydrocarbon accumulation in the late stage, mainly in the structure-strata and structural reservoirs. Through the establishment of deep-water hydrocarbon accumulation modes in different types of basins, it is pointed out that the key directions of deep water exploration in different structural segments are: the Upper Cretaceous overlying superficial fan in the northern segment, the Paleogene-Neogene ramp system in the equatorial zone and the front margin of the deep-water thrust zone , The middle stretch salt-bearing upper turbidite and diabase-thrust belt sub-salt carbonate rock, the southern upper Cretaceous and fault block slope waterway.