Multi-phase Thermal History and its Impact on Hydrocarbon Development (Reggane Basin, Algeria)

A comprehensive study on basin development and hydrocarbon potential of the Palaeozoic of the Reggane Basin was performed along a transect from the eastern basin margin into the basin. Palynostratigraphic analysis enabled detailed correlations along the transect, showing continuous deposition from the Silurian to the Lower Carboniferous with some differences between proximal and distal wells. In the Upper Carboniferous a complex basin development is observed due to the Variscan orogeny. All wells are penetrated by magmatic intrusions related to the Latest Triassic ‘CAMP’ volcanism, but the number, frequency and stratigraphical position of the dykes differs between the wells.

Stratigraphically controlled subsidence history and integrated organic maturation analysis decipher the thermal history and hydrocarbon generation within the Reggane Basin. It indicates a two-phased thermal history leading to two phases of hydrocarbon generation. Continuous burial until the Top Lower Carboniferous led to middle – upper gas window maturation of Silurian source rocks in all wells, activating the Silurian - Lower Devonian hydrocarbon system already in the Palaeozoic. Late Triassic ‘CAMP’ related magmatic dykes led locally to secondary heating, leading in one well to increased maturation of Upper Devonian source rocks, activating additionally a second Upper Devonian - Lower Carboniferous hydrocarbon system.