Abstract: Evaluation of hydrocarbon potential in Bechar Oued Namous basin

BRAIK F, S. MERABET, R. HACHED

The Bechar-Oued Namous is located on the northern margin of the Saharan platform. It is bordered on the north by the Atlas trough Timimoun basin and Azzen high represent its southern limit.

The main reservoirs in this area are Siegenian and Famennian sandstones which are situated in Meharez- Oued Namous high. The upper Dkhissa formation of the Siegenian age is made up of a lowstand systems tract and transgressive systems tract. This formation has stratigraphy, developed in a deltaic to open marine environment, favoring the presence and the development of potential sandstone reservoirs within Meharez- Oued Namous high. In the same way, lowstand and highstand systems tract identified in the Famennian shaly- sandstone of Marhouma Formation present good porosities. These systems tract correspond to two deltaic phases. The diagenetic phenomena control the petrophysical properties of these sandstone bodies. Secondary porosities related to the different dissolution phases have been confirmed.

Oil-prone source rocks in the late Devonian and lower Silurian sequences have been proven from well and outcrop sections in and around the Bechar-Oued Namous basin. These are likely to be mature for hydrocarbons on the highs in the basin and over mature in the lows.

Gas-prone source rocks occur in abundance in the Visean and the Westphalian, and the Hercynian folding which affected this zone has created a number of structural traps. Early Carboniferous normal faults have been reactivated as reverse faults during Hercynian compression. The generation of hydrocarbons was projected to be synchronous with Hercynian structuring.

AAPG Search and Discovery Article #90942©1997 AAPG International Conference and Exhibition, Vienna, Austria