1 ) Overview
Missour Basin, with an area of about 16 840 Km², is a part of the Eastern Meseta. It is surrounded by the Middle and the High Atlas chain, and is separated from the High Plateaux Basin by Mechkakour Mountain.
2 ) Data base
3 415 km of multifold 2D seismic lines have been acquired andfive wells drilled.
3 ) Tectonic and Sedimentary Evolution
3-1 ) Tectonic Evolution
During Triassic and Jurassic time, extension, related to Atlantic opening, created the Atlas troughs, and produced a system of grabens and / or half grabens.
Structural inversion of the Atlas troughs commenced during the Late Cretaceous. In Missour Basin, which behaved as a platform, inverted half grabens, positive flower structures and compressional anticlines are the main responses.
3-2 ) Sedimentary Evolution
The Upper Triassic sediments begin with a fining upward TAGI formation followed by a thick and widespread salt intercalated by Basalts. The Jurassicformations are mostly carbonates and dolomites and marls of Liassic-Bathonian age.
During upper Cretaceous, carbonates, sandstone, shale and anhydrite were unconformably deposited over the Jurassic facies in sub basins. Followed by a thick succession of conglomerates, sandstones, marls and limestones of Cenozoic age
4 ) Système pétrolier
4-1 ) Source rock
4.2 ) Reservoir Rocks
For Triassic reservoir, TAGI Formation is the most important hydrocarbon bearing reservoir. This reservoir has revealed gas and condensate in Essaouira Basin in the Western Meseta and recently gas and condensate in Talsint area. This reservoir is also the main target in some of the giant fields in neighboring Algeria. RR-1 well to the southexceeds 400 meters. TAGI porosity ranges from 6 % to 11-15 % in the wells and up to 25 % in the outcrops. For Jurassic reservoir, Lower Liassic and Dogger carbonates are the main reservoirs:
4.3 ) Seals
The intercalated shale to the sand bodies, and the overlying salt, which is a regional cover, are an effective seal for the TAGI reservoir.
The Jurassic reservoir is sealed by the intercalated marls to the limestone reservoir, and by the Lower and Middle Jurassic marls.
5 ) Prospects
Six prospects have been defined from the last studies, and all these structures are related to Flower Structures with Mesozoic targets (Prospect A1, A2, B, C, F and G).
Recent reprocessing of some seismic lines in 2005 has improved seismic images bellow the basalts and has allowed the identification of some prospects in the Paleozoic section close to OSD-1 well area. These prospects are related to Hercynian thrusting.
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Basin
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Missour
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Basin type
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Rift - Intermountain basin
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Area
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16 840 Km²
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Exploratory wells
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5
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2D Seismic / 3D Seismic
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3.415,00 Km of 2D
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Source Rocks
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Carboniferous (III) and Silurian (II)
Domerian (II-III)
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Reservoir Rocks
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Carboniferous sandstones – TAGI – Jurassic carbonates
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Seal Rocks
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Carboniferous shales, salt and Jurassic marls
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