N. Yahi1, R.G. Schaefer1, R. Littke2
(1) Institute of Petroleum and Organic Geochemistry, Julich, Germany
(2) Aachen University of Technology, Aachen, Germany
ABSTRACT: 2D Modeling of Fluid Flow and Destruction Versus Conservation of Hydrocarbon in the Berkine Basin, Algeria
Current hydrocarbon production in the Berkine Basin is from reservoirs of Triassic age. As Paleozoic reservoirs are often very deep, exploration has concentrated on the Triassic play. Hydrocarbons derived from two separate, thinly laminated, organic-rich shaly calcareous rocks of Upper Devonian (Frasnian) and Lower Silurian (Llandoverian-Wenlockian) age and are located in different trap types. The application of organic geochemistry and an extensive basin modelling study were carried out in order to improve the understanding of the petroleum charge in the basin. Maturity data reflect the Late Cretaceous-Tertiary burial and are consistent with a 60-63 mW/m2 heat flow in the vicinity of the anticlines and 50 mW/m2 heat flow farther away from the folded area. A two-dimensional basin modeling study revealed the importance of the rate of the Hercynian erosion on hydrocarbon generation and trapping efficiencies. The model shows that a Cretaceous-Tertiary petroleum generation and emplacement for both source rocks can better explain the different oil and gas fields than an earlier, Hercynian event. The model indicates also two Triassic-related petroleum systems. The fields in the central producing areas derived mainly from the Frasnian source beds. Extensive vertical migration along faults of oils generating in these sediments is prevented by evaporitic seals deposited during the Early Jurassic. The fields along the El Biod-Messaoud ridge derived from the Lower Silurian source rock. Migration from the source to the Triassic reservoirs was initiated by expulsion toward underlying Paleozoic reservoirs, followed by accumulation in local traps and dismigration into the overlying traps after the Cretaceous compressive movements.
AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado