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Площадь: 283853.12 км²
Pelagian Basin
The Pelagian Province is generally located within the offshore shelf area of east-central Tunisia and northern Libya—the Gulfs of Hammamet and Gabes (Fig. 1). The western and southern boundaries are onshore.
The “Bou Dabbous–Tertiary (Cenozoic) Total Petroleum System” (Klett 2001) coincides with the potential extent of petroleum being generated by, and migrating from, Lower Eocene Bou Dabbous source rocks. The Bou Dabbous Formation is dark brown marl and mudstone containing type I and II kerogen and ranging in thickness from 50 to 300 m. TOC ranges from 0.4 to 4% and maturation is described as early mature to mature (Klett 2001; Mohamed et al. 2015). Petroleum migrated laterally into adjacent or juxtaposed reservoirs and vertically along faults or fractures.
Fig. 1 Pelagian Basin (offshore Libya and Tunisia) Bou Dabbous-Cenozoic total petroleum system
Reservoir rocks include lateral equivalents of the Lower Eocene Bou Dabbous Formation, such as the, El Garia fractured limestone, Jdeir equivalent in Libya, and Jirani dolostone (Mriheel and Anketell 2000). The El Garia Formation was deposited on a shallow north to NE facing ramp composed of a belt of nummulitic wackestone–grainstone (Macaulay et al. 2001; Anketell and Mriheel 2000). Most hydrocarbon production is from the seaward side of the nummulite bank trend including Bourri, Ashtart, Sidi El Itayem, and Zarat fields. The giant Ashtart and Bourri fields are located on structural highs which protruded into the basin and were almost surrounded by Bou Dabbous source rocks; therefore, potential migration pathways are short (Racey 2001; Racey et al. 2001). Other reservoirs are Oligocene to Miocene Ketatna limestone; the Middle Miocene Aïn Grab limestone; and the Middle Miocene Oum Douil sandstone and laterally equivalent Birsa and Mahmoud sandstones. Sandstones vary from shoreface to shallow marine and typically exhibit excellent reservoir quality of 30–35% porosity and good permeability from 500–1100 mD. Sedimentary paleo-environment distribution varies from proximal deltaic/fluvial deposits in the northern part of the high central Birsa horst to a delta front and pro-delta coastal and shelf shoreface and shoreline channelized deposits in the surrounding borders of grabens (Bedir et al. 2016).
Known accumulations are in fault blocks, low-amplitude anticlines, high amplitude anticlines associated with reverse faults, wrench fault structures, and stratigraphic traps. Most of the traps formed before the Middle Miocene. Seals include Eocene and Miocene mudstone and carbonate rocks.
Data source: Regional Geology and Petroleum Systems of the Main Reservoirs and Source Rocks of North Africa and the Middle East. D. Lučić and W. Bosworth. 2019
Следующий Бассейн: Western Desert