MANSOURI,A. L.,Arabian Gulf Oil Co.,A. EL-ARNAUTI, Univ. of Garyounis, B.THUSU, Arabian Gulf Oil Co. & North Africa Petroleum Research Group, Univ. College London, E.YANILMAZ,Arabian Gulf Oil Co., and D.P. HUFFMAN, Arabian Gulf Oil Co.

Abstract: Current Investigation of The Geology of Northeast Libya and Its Hydrocarbon Implications

Arabian Gulf Oil Company, Benghazi, has undertaken intensive basinal analysis in Northeast Libya, an area of four major structural provinces: Cyrenaica Platform, Jabal Akhdar Uplift, Marmarica Trough and Solouq Depression. A Mesozoic hingeline separates the Cyrenaica Platform from the other three provinces. While the Cyrenaica Platform remained as a stable area after Paleozoic times, Marmarica, Solouq and Jabal Akhdar areas formed into basins. The later basin was subjected to inversion in Late Cretaceous.

In Cyrenaica Platform thick Paleozoic sequences of shallow marine to marginal marine sandstone, limestone and shale disconformably underlie non-marine to paralic Mesozoic sediments of Triassic-Early Cretaceous age. Late Cretaceous and Tertiary transgression developed the Cyrenaica Platform into a continental shelf. Jabal Akhdar incorporates a thick Lower Mesozoic sequence of claystone, interbedded with siltstone and sandstone, grading to carbonates in the northwest followed by post inversion Upper Cretaceous and Tertiary shales and argillaceous limestones. In Marmarica Trough area, thick deep marine Jurassic-Lower Cretaceous clastics are overlain by Upper Cretaceous and Tertiary carbonates and shales. Solouq Depression is characterized by a thick sequence (>16000 ft.) of Upper Cretaceous and Tertiary limestones, argillaceous limestones and dolomites with minor intervals of shale (Fig. 1).

Paleozoic shales in Cyrenaica Platform, Jurassic and Lower Cretaceous shales in Jabal Akhdar and Marmarica and Upper Cretaceous shales in Solouq are considered potential oil and gas source rocks. Reservoir rocks are the porous Devonian-Carboniferous sandstones and carbonates in Cyrenaica Platform, Jurassic-Lower Cretaceous sandstones-carbonates and Upper Cretaceous carbonates in Jabal Akhdar, Jurassic-Lower Cretaceous sandstones -carbonates in Marmarica and Upper Cretaceous-Lower Tertiary carbonates in Solouq (Fig. 2).
 
 

Fig. 1. Litho and chronostratigraphy of the main structural provinces of Northeast Libya.

Fig. 2: Location and principal petroleum systems of Northeast Libya.

AAPG Search and Discovery Article #90923@1999 International Conference and Exhibition, Birmingham, England