Tectonostratigraphic evolution of the new frontier Foram Basin and implications for hydrocarbon potential, Western Desert, Egypt

Abstract

The Western Desert of Egypt is an important hydrocarbon province as it consists of many petroliferous sedimentary basins. The researchers and petroleum companies are interested in exploring the new frontier sedimentary basins and evaluating their hydrocarbon potential. Given this point of view, the current study attempts to assess the new frontier sedimentary basin in the Western Desert of Egypt, named Foram Basin (FB), using various geophysical and geological methods, including the magnetic, gravity, and seismic methods in addition to the petroleum system and basin analysis modeling. The magnetic data analysis uses various techniques, including power spectrum and source parameter image, total magnetic intensity (TMI), reduction to the pole (RTP), regional-residual separation, and tilt derivative. The used techniques in the interpretation of gravity data include Bouguer gravity, power spectrum, regional-residual separation of Bouguer gravity, tilt derivative of the Bouguer gravity and gravity inversion, and 2D gravity modeling, in addition to the tentative basement depth based on the gravity inversion and 2D gravity modeling for the nine profiles. The main results of these techniques indicate that the main structural trend is NE-SW and the depth to the basement ranges from 1.8 to 5 km comprising two depocenters.Two-thirds of the sedimentary basin fill is a Paleozoic succession and one-third is a Mesozoic-Cenozoic succession. Therefore, the FB is thought to be a Paleozoic basin. The Paleozoic-Mesozoic stratigraphic framework of the FB was classified into six seismic sequences separated by the seven seismic boundaries. The main regional structural trend of the FB is NE-SW, the same trend as that of the Paleozoic Kufra Basin in Libya. In the FB, the major structural trend in the Early Paleozoic is NE-SW, whereas it is E-W in Late Paleozoic. Moreover, in Mesozoic Jurassic time, the dominant trends are E-W and ENE-WSW, and in Middle Cretaceous is ENE-WSW and in Upper Cretaceous are E-W and NE-SW. Regarding the tectonic subsidence rate, the FB passed three tectonic phases. The first tectonic phase has a high subsidence rate that occurred in the Paleozoic, resulting in the deposition of most of the sedimentary succession. The second and third tectonic phases occurred at a relatively low subsidence rate, resulting in the deposition of Mesozoic-Cenozoic deposits. The Paleozoic Silurian Kohla source rock passed the early generation phase in the Early Eocene (50 Ma) and reached a maximum generation rate of 2.77 (mg/gTOC^my) in Late Oligocene (27 Ma) that is considered a very low rate and did not allow for oil expulsion.