1 ) Overview
The Beni Znassen-Beni BouYahi area, located in north-eastern Morocco, is developed within the easternmost portion of the southern Rif mountain chain between the Mediterranean cost to the North, The Eastern Prerif to the West and the northern edge of the High Plateaux to the South.
2 ) Data base
- Seismic data: Only two seismic campaigns (2D) have been acquired in the Beni Znassen basin. The first (843 Km) was shot in 1985. The last seismic campaign (311Km) was acquired in 2001 covering the western part of the basin where the nappes complex is outcropping.
- Wells data: The Beni Znassen basin is practically unexplored. No well has been drilled in the area yet.
3 ) Basin fill and geometry
Sedimentary fill consists of more than 6000 m of Mesozoic and Cenozoic sediments, which is covered by the complex of the Eastern Prerif nappes itself is overlain by Tertiary clastic sediments.
4 ) Petroleum system
4-1 ) Source Rock
The main source rock to be considered within the area is Domerian/Toarcian in age similar to the defined sources in the Middle Atlas and in the western part of the Prerif.
A Cretaceous source rock could also exist within the nappes complex. This source seems to be the origin of artificial oil production made during the twenties in Tizeroutine.
4-2 ) Reservoir Rocks
Expected reservoirs, within the area, are Triassic sandstones, L. Jurassic limestone and Upper Jurassic deltaic and turbiditic sandstones.
4-3 ) Seals
Seals are provided by the marls deposited during the Toarcian time for Triassic and L. Jurassic reservoirs and the complex of nappes for the Middle and Upper Jurassic sandstones.
4-4 ) Traps
Traps are structural and lie with anticlines, back-thrust and faulted and faulted blocks.
Combined traps could exist within the Triassic objectives.
5 ) Play concepts
The newly acquired seismic data and recent integrated studies have permitted to develop three new play concepts within the Beni Znassen basin.
The defined play concepts consist of Triassic, lower Jurassic and Middle Jurassic thrusted structures in Hassi Berkane area and Triassic, Jurassic and Tertiary folded sandstones and carbonates below the complex of nappes.
6 ) Prospects and leads
Developed lead in Hassi Berkane area, within the foreland, is related to a probably saliferous ramp structure. Triassic sandstones, Lower Jurassic limestone and Middle Jurassic sandstones represent the main objectives. Hydrocarbons are interpreted to be sourced from Lower Jurassic and Middle Jurassic shale.
In the north-eastern part of the basin, developed lead is related to a subnappe anticline structures. The Cretaceous and Lower Jurassic shale represents the source rocks. Maturation and migration of hydrocarbons may have occurred during the Tertiary after the emplacement of the nappes.
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Basin
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Beniznassen Basin
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Basin type
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Rift
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Area
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10 000 Km²
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Exploratory wells
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0
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2D Seismic/3D Seismic
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1.154,00 Km of 2D
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Source Rocks
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Domerian/Toarcian and the Cretaceous
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Reservoir Rocks
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Triassic sandstones; Lower Jurassic limestone and Upper Jurassic deltaic and turbiditic sandstones.
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Seal Rocks
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Marls from Toarcian and the complex of nappes for the Middle and Upper Jurassic sandstones.
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