1 ) Overview
The High Plateaux Basin, 20 036 km² is limited by the Mechkakour Lineament at the west and stretches eastward to Morocco-Algeria borders. The SBK-1 gas discovery well in Talsint area has given a real boost to the exploration of the untapped reserves of this vast zone.
2 ) Data base
Since 1974, a total of 4110 km of 2D seismic lines has been acquired in the area. In the year 2003, 498 km² of 3D seismic was shot on the Tendrara structure. During 1963- 2006 period, six core drills were achieved for stratigraphic purpose and seven exploratory wells were spud.
3 ) Tectonic and Sedimentary Evolution
3-1 ) Tectonic Evolution
The High Plateaux Area, like its surroundings, underwent three main orogenic phases:
- The Hercynian Phase with thrusting and magmatic intrusives.
- The Triassic - Jurassic extension phase with normal faulting.
- The Alpine compressive Phase causing the inversion of the Atlas and halo kinesis, especially in the southern part of the area.
3-2 ) Sedimentary Evolution
The Siluro-Ordovician, and the Devonian periods are represented by shales, quartzites, carbonates, sandstones, and claystone. The Carboniferous is composed of claystone and siltstone of Visean-Namurian age. Coal-bearing clastics of Westphalian age are present in the north, in Jerada coal mine, and in OSD-1 well in Missour Basin. The Triassic series are composed of TAGI overlain by salt beds and basalt. Jurassic formations are mostly carbonates and dolomites of Liassic-Bathonian age. The Cretaceous and the Cenozoic are characterized by conglomerate, limestone, shales and anhydrite deposits.
4 ) Petroleum Systems
4-1 ) Hydrocarbon Occurrences
SBK-1well, spud in 2000 in the Talsint area, revealed gas and condensate accumulation in the TAGI reservoir.
4-2 ) Source rocks
- Paleozoic source rocks: Visean- Namurian source rock analysis from Tendrara wells revealed gas prone type III shale with a TOC value of 0.5 to 1.5 %, and a maturation rate of 1 to 1.3 per cent Ro.
- Mesozoic source rocks: Lower Jurassic black shales, encountered the surrounding High and Middle Atlas belts, reveal rich oil prone type II black shales (TOC is up to 8% in the Middle Atlas trough (Issouka area) and up to 2% in the High Atlas).
4-3 ) Traps
- Structural traps: reverse fault- related features such as thrust sheets, half grabens, tilted blocks, rollover anticlines, and salt- related traps.
- Stratigraphic traps: pinch outs, reefs and sand lenses.
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Basin
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High Plateaux
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Basin type
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Rift
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Area
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20 036 km²
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Exploratory wells
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7
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Gas discoveries
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Gas and condensate
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2D Seismic/3D Seismic
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4.110,00 Km of 2D / 498,00 km² of 3D
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Source Rocks
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Visean – Namurian (III); Lower Jurassic black shales (II)
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Hydrocarbon type
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Gas
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