--> Abstract: Hydrocarbon Potential of an Under-Explored Frontier Basin. The Zag Basin of Morocco, by Lewis Gillhespy and John Exton; #90072 (2007)

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Hydrocarbon Potential of an Under-Explored Frontier Basin. The Zag Basin of Morocco

Lewis Gillhespy1 and John Exton2
1Petro-Canada, London, United Kingdom
2Barrowden Consultants Ltd, London

The approximately 200,000 km2 Zag Basin occupies parts of Algeria, Morocco and Mauritania and is one of three large intra-cratonic sedimentary basins (Reggane; Taoudeni; Zag) developed on the West African craton. It experienced its greatest exploration interest between the late 1950's and early 1970's with the drilling of 15 exploratory wells in the Algerian and Moroccan areas, based on surface geology and a limited number of single fold seismic lines. The Zag Basin has a very low drilling density of 1 well per 13,300 km2 with over 60% of the wells drilled reporting shows of oil or gas, or with recovered hydrocarbons from open-hole tests. No drilling activity has been carried out since 1971 as interest in North Africa has been focused elsewhere. However recent success in neighbouring basins has attracted renewed attention.
Petro-Canada, in partnership with ONHYM, has used extensive geological field work, the application of modern technologies (airborne gravity and magnetic data) and innovative exploration to positively re-evaluate the petroleum system. Detailed mapping and analysis of outcrop samples has established the presence of regionally extensive shales of original source rock quality. A number of potential reservoir intervals, conformably capped by widespread shale seals, have been identified. These reservoirs occur within large, long-wavelength, low-amplitude fold structures with potential for trapping significant hydrocarbon volumes.
Large amounts of gas have been trapped in a number of reservoirs in the Palaeozoic Reggane, Ahnet and Timimoun Basins, despite reported source rocks being post-mature for hydrocarbon generation. Basin modelling carried out by Petro-Canada indicates a similar complex burial and thermal history within the Zag Basin, making it one of the largest prospective frontier basins in North Africa.

 

AAPG Search and Discovery Article #90072 © 2007 AAPG and AAPG European Region Conference, Athens, Greece