AAPG Bulletin, v. 85, no. 8 (August 2001), pp. 1439–1467 1439 Petroleum generation and accumulation in the Berkine basin, eastern Algeria Noureddine Yahi, Rainer G. Schaefer, and Ralf Littke ABSTRACT The Berkine (Ghadames) basin is regarded as an important hydro- carbon play in eastern Algeria. An evaluation of organic source fa- cies, the application of petroleum geochemistry, and an extensive basinmodelingstudywerecarriedouttoimprovetheunderstand- ingofthepetroleumchargeofthebasin.Geochemicaldataindicate that the Llandoverian–Wenlockian and the Frasnian hot shales are the most important oil-prone source rocks for the known hydro- carbon accumulations in the basin. Maturity data reflect the Late Cretaceous–Tertiary burial and are consistent with a 60–63 mW/ m 2 heatflowinthevicinityoftheanticlinesand50mW/m 2 heat flow farther away from the folded area. A two-dimensional basin modeling study revealed the importance of poorly constrained pa- rameters, such as the amount and rate of Hercynian erosion, on hydrocarbongenerationandtrappingefficiencies.Themodelshows thataCretaceous–Tertiarypetroleumgenerationandemplacement for both source rocks can better explain the different gas and oil fieldsthancananearlier,Hercynianevent.Thefaultsrelatedtothe Triassic–Jurassic rifting are most certainly permeable and can be consideredasmajormigrationpathwaysforpetroleum.Incontrast, theoverpressurethatdevelopedalongtheElBiod–HassiMessaoud axis in the Ordovician reservoirs was probably caused by the low permeability of the faults bounding the anticlines that therefore prohibitedanylateralorverticalfluidmovements.Themodelalso indicatestwopetroleumsystemsthathaveTriassicreservoirs:(1)a Frasnian-sourced system that is confined to the central part of the basin and (2) a Llandoverian–Wenlockian–sourced system in the western part of the basin. Migration into Paleozoic reservoirs was followedbydismigrationintooverlyingTriassictrapsaftertheCre- taceous compressive movements. INTRODUCTION North Africa includes several significant hydrocarbon provinces of which the most important are the Sirte basin of Libya and the Copyright 2001. The American Association of Petroleum Geologists. All rights reserved. Manuscript received July 13, 1999; revised manuscript received August 10, 2000; final acceptance October 10, 2000. AUTHORS Noureddine Yahi  Institute of Petroleum and Organic Geochemistry, Department of Chemistry and Dynamics of the Geosphere, Research Center Ju ¨ lich, 52425 Ju ¨ lich, Germany; current address: Sonatrach, Exploration Division, Avenue du 1er Novembre, 35000 Boumerdes, Algeria; noureddine_yahi@yahoo.fr Noureddine Yahi obtained his first academic degree in engineering, petroleum geology, from the Algerian Petroleum Institute in 1989. Between 1989 and 1996 he worked for Sonatrach as a petroleum geologist. From 1996 to 1999 he conducted a dissertation in geology under the guidance of D. H. Welte and R. Littke at the Institute of Petroleum and Organic Geochemistry, Research Center Ju ¨lich, Germany. In 1999 he received his doctoral degree from the Department of Earth Sciences at Aachen University of Technology (RWTH Aachen), Germany. His scientific interests include organic geochemistry of petroleum and source rocks, as well as basin modeling studies. Rainer G. Schaefer  Institute of Petroleum and Organic Geochemistry, Department of Chemistry and Dynamics of the Geosphere, Research Center Ju ¨ lich, 52425 Ju ¨ lich, Germany; r.g.schaefer@fz-juelich.de Rainer Schaefer is a staff research scientist with the Institute of Petroleum and Organic Geochemistry at the Research Center (formerly KFA) Ju ¨lich, Germany. He obtained his first academic degree in chemistry (Diplom-Chemiker) in 1967 at Freie Universita ¨t, Berlin, and, in 1970, he received his doctoral degree after conducting a dissertation in chemistry on heterogeneous catalysis at Max-Planck-Institut fu ¨r Kohlenforschung, Mu ¨lheim/Ruhr, Germany. Since joining KFA Ju ¨lich in 1975, he has published numerous articles on organic and petroleum geochemistry topics. His current research interests include the reaction kinetics of petroleum generation and the geochemistry of low molecular weight hydrocarbons. Ralf Littke  Institute of Geology and Geochemistry of Petroleum and Coal, Aachen University of Technology, Lochnerstr. 4-20,