Petroleum generation modeling of the Late Cretaceous coals from the Jiza-Qamar Basin as infer by kerogen pyrolysis and bulk kinetics

Abstract

Abstract The petroleum generating potential of the Late Cretaceous coal within the Mukalla Formation is evaluated. Bulk and quantitative pyrolysis techniques and organic petrology were used to characterize the kerogen composition, generative potential and kinetic models to determine the variability of the organic matter and their effect on the timing of petroleum generation. These measurements identified one major organic facies containing an oil-prone Type II/III kerogen, with HI values >300 mg HC/g TOC that produces mainly paraffinic and paraffinic–naphthenic–aromatic (P–N–A) oils with high wax contents. Bulk kinetic analysis on Late Cretaceous coal samples reveal a relatively broad distribution of activation energies (42–69 kcal/mol). Using a generic heating rate of 3.3 °C/My, the onset temperature for oil generation (TR 10%) is ∼139 °C and the peak generation temperature (geologic Tmax) range from 150 to 167 °C. A 1D model predicts that the Mukalla coals in the Jiza-Qamar Basin began oil generation at ∼40 My and reached peak generation ∼20–15 My ago. Therefore, the Mukalla coals could have be generated mature oils in the Jiza-Qamar Basin.