Shiyou shiyan dizhi (May 2023)
Structural characteristics and exploration fields in passive continental margin basins of Central Atlantic
Abstract
The petroleum resources of the passive continental margin basins in the Central Atlantic are rich, but the insufficient knowledge of basin structural characteristics and accumulation conditions in the area restricts the exploration of deepwater oil and gas. Based on the integral analysis of seismic, drilling, gravity anomalies and magnetic anomalies data, the basin structural characteristics and hydrocarbon accumulation conditions in deepwater area of the passive continental margin basins of the Central Atlantic are studied and the exploration fields are predicted with the Senegal and Scotia basins as key anatomical objects. It can be concluded that the passive continental margin basins of the Central Atlantic have experienced three evolution stages: the rift period, the transition period and the drift period, with corresponding development of three tectonic layers: the rift layer, the depression layer and the continental margin layer, and the basin structures are controlled by transform faults and basement properties. From Triassic to Early Jurassic rift period, a series of horst-graben structures were formed, and the sediments were mainly continental ones such as rivers, lakes and deltas. From Middle to Late Jurassic transition period, the marginal ridge or submarine uplift zone were developed due to the activity of transform faults, and a landward high terrain limited environment was formed due to the stretch, thinning and subsidence of the Paleozoic weak basement, providing a favorable condition for the development of source rocks in the depression layer. During Cretaceous drift period, platform margin reef and delta-slope floor fan reservoirs were developed. Both the deepwater slope floor fan in the Scotia Basin and the platform margin reef in the Senegal Basin have great exploration potential.
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