Thermal maturation assessment of multiple organic-rich intervals in the Khatatba Formation and its influences on hydrocarbon potentiality, North East Abu Gharadig Concession, elucidated by 1D basin modeling approach

Abstract

ABSTRACT Hydrocarbon generation and expulsion simulations of multiple organic-rich intervals with diverse kerogen types in the Khatatba Formation were performed. Generally, the organofacies exhibit an excellent generation potential for liquid hydrocarbons, gas plus oil and/or gas. The 1D forward approaches have been executed for the complex tectonic and basin-fill history. The spatial distribution of the Khatatba organofacies and allocation of significant discoveries from the Khatatba Formation are aligned perpendicular to the NE-SW Jurassic Fault System. The organic-rich intervals underwent several heating episodes throughout its burial history predominantly during the Cretaceous Rifting phase. Likewise, the organofacies underwent episodic expulsion of gas derived from either primary cracking (kerogen type III) or secondary cracking of oil (kerogen type II). The oil prone type II kerogen entered the oil window at JD-4 well close to the Albian whilst the wet-gas window since late Albian. Conversely, gas prone type III kerogen attained the dry-gas window from the time of early Oligocene at the JD-4 well prior to the wet-gas window of the JG-2 well (late Oligocene). Nevertheless, gas prone type III kerogen never reached the dry gas window at JG-2 well due to its low thermal maturation level. The burial effect, attributable to the thick basin-fill sediments (Masajid, Alam El Bueib, Abu Roash and Khoman formations), accelerated the thermal maturation at the JD-4 well. However, the organofacies revealed neither thermogenic gas generation nor gas secondary cracking at the JG-2 well and nix expulsion. The expelled hydrocarbon assumed to migrate laterally and near vertically from the southeastern part towards the north western part.