Source rocks evaluation, hydrocarbon generation and palynofacies study of late cretaceous succession at 16/G-1 offshore well in Qamar Basin, eastern Yemen

Abstract

Subsurface Late Cretaceous succession has been recovered from 16/G-1, an offshore exploratory well that located in the Qamar Basin, eastern Republic of Yemen. This paper deals with the study of source rocks, maturation, hydrocarbon evaluation, and palynofacies of the Late Cretaceous Mukalla and Dabut Formations of the Mahra Group. These two formations consist of an intercalation of argillaceous, carbonates, siltstones, sandstones and coal layers. The sedimentary organic matter as amorphous organic matter, phytoclasts and palynomorphs are investigated and identified under transmitted light microscope. Spores, pollen, dinoflagellates, algae, fungi, and acritarchs in addition to foraminiferal lining test have been also identified. The optical and organic geochemical studies were used to evaluate the source rock, maturation and its hydrocarbons potentiality. The thermal alteration index, vitrinite reflectance, rock-eval pyrolysis, and palynofacies were also used. The upward increase in the relative abundance of marine versus terrestrial input reflects a major marine transgression and retregration cycles from Campanian to Maastrichtian stages. The Mukalla and Dabut Formations are late immature to mature stages with kerogen types II and III. The hydrocarbons generation potentiality of two formations is oil and wet gas prone indicators.