Seismic Tectono-Stratigraphy and Hydrocarbon Implications of Lowstand Deep Marine Oligo-Miocene Siliciclastic Reservoirs in the Northern Levant Basin

Abstract

The recent discoveries of commercial gas fields in the Miocene sandstones structural/stratigraphic traps along the southern sector of the Levant Basin drove the interest of the industrial and scientific community. For that, basin tectonic structuring and seismic sequence stratigraphy study of Oligo-Miocene Siliciclastic deposits interval horizons have been undertaken to follow and precise stratigraphic traps. This work based on the analysis and interpretations of new regional E-W and N-S 2D seismic lines calibrated to wells data and lithostratigraphic outcrops had highlighted the basin configuration and sequence deposits infill nature and distribution of Oligocene and Miocene lowstand Siliciclastic reservoirs around the north Levant basin. Oligo-Miocene infilling horizons of the basin is controlled by deep-seated inherited and reactivated faults mainly oriented WNW-ESE and NE-SW. Based on their ages and seismic sequence stratigraphy concepts, they are interpreted as organized in 3 s order sequences composed by 5 Oligocene, 4 Lower Miocene, and 5 to 7 Middle-Upper Miocene third order seismic sequences system tracts. Early lowstand horizons are interpreted as presenting a downlap prograding sigmoid, oblique and mounded slope fans system tracts and basin floor mounds of large turbidites sheets and lobes overlain by late lowstand incised channels, canyons and levees and transgressive onlaps and toplaps. These system tracts are deformed and structured by Tertiary faults and Anticlines and synclines folds. Reservoir fair maps domains of the different lowstand system tracts highlight three main depositional sectors: slope, toe of slope and basin floor. They are vertically and laterally superposed and shifted. These clastic deposits present progradational configurations of slope fans as well as sheeted configurations channels, canyons and levees and basin floor lobes. The documented analogues in the Lebanon, Cyprus and Palestine continental coast outcrops are reported as deposits of gravity slides and slumps, turbidites, debris flows, mass flows, sandstones, and conglomerates alternated by hemipelagic marls. Hydrocarbon structural and stratigraphic trap types are discussed according the highlighted reservoir sequence structuring and system tract distribution.