Geng, K.; Wen, Z.; Wang, X.; Wang, Z.; He, Z.; Song, C.; Ji, T.; Li, H. Architecture Differences and Hydrocarbon Accumulation in Passive Continental Margin Basins in East Africa. Appl. Sci.2023, 13, 11203.
Geng, K.; Wen, Z.; Wang, X.; Wang, Z.; He, Z.; Song, C.; Ji, T.; Li, H. Architecture Differences and Hydrocarbon Accumulation in Passive Continental Margin Basins in East Africa. Appl. Sci. 2023, 13, 11203.
Geng, K.; Wen, Z.; Wang, X.; Wang, Z.; He, Z.; Song, C.; Ji, T.; Li, H. Architecture Differences and Hydrocarbon Accumulation in Passive Continental Margin Basins in East Africa. Appl. Sci.2023, 13, 11203.
Geng, K.; Wen, Z.; Wang, X.; Wang, Z.; He, Z.; Song, C.; Ji, T.; Li, H. Architecture Differences and Hydrocarbon Accumulation in Passive Continental Margin Basins in East Africa. Appl. Sci. 2023, 13, 11203.
Abstract
Based on the plate tectonic theory, using seismic, geology, and public literature data, the proto-type basins and lithofacies paleogeography during the main geological periods of the passive continental margin of East Africa are restored, and the architecture characteristics of the basins and the differences in sedimentary fillings are analyzed. Combined with the dissection of discovered oil and gas reservoirs, four types of hydrocarbon accumulation models are established, the favorable hydrocarbon accumulation combinations (plays), and the next exploration directions in this region are explored. The passive continental margin basins in East Africa experienced three proto-type stages: intracontinental aborted rift during the Late Carboniferous-Triassic Karoo period, intracontinental-intercontinental rift during the Jurassic period, and passive continental margin basin since the Cretaceous period. Affected by the difference in sedimentary filling thickness between the rift period and depression period, four types of passive continental margin basins are formed: rifted type, depressed type, faulted depression type, and reformed delta type. The maximum sedimentary thickness of the rifted basins during the rift period is greater than 3500 m, and that during the depression period is less than 4000 m, forming a "single-source structure type" hydrocarbon accumulation model. The exploration of rifted basins should focus on giant structural traps at the top of the rifted sequences. The maximum sedimentary thickness of the depressed basins during the depression period exceeds 4000 m, forming a "single-source fan group type" hydrocarbon accumulation model. The dominant exploration directions of depressed basins are sedimentary sand bodies and structural-lithologic traps during the depression and drift periods. The maximum sedimentary thickness of the faulted depression basins during the rift period is greater than 3500 m, and that during the depression period is greater than 4000 m, forming a "double-source and double-combination type" hydrocarbon accumulation model. The exploration of rifted basins should focus on giant slip-collapse-debris flow sedimentary sand bodies on the upper and middle slopes. In addition to the large sedimentary thickness of the early rift and the central depression, the delta thickness of the reformed delta basins during the late depression period since the Miocene is more than 4000 m, and four structural belts (growth fault, mud diapir, thrust fold, and foredeep gentle slope) were formed from onshore to offshore, forming a "three-source and multi-combination type" hydrocarbon accumulation model. All four structural belts can form giant oil and gas fields.
Environmental and Earth Sciences, Geophysics and Geology
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