Maturity estimation for Type II-S kerogen using Raman spectroscopy – A case study from the Najmah and Makhul Formations in Kuwait

Abstract Raman spectroscopy is used to estimate thermal maturity of shale samples collected from seven wells in the Najmah Formation in Kuwait, encompassing a range of maturities between 0.80 and 1.40%VRE. The Najmah Formation contains kerogen Type II-S (S/C > > 0.04) and therefore, maturity correlations for Type II are not applicable due to differences in organic material structure, kinetics and thermal transformation pathways. A new correlation is proposed for the purpose of thermal maturity estimation in Type II-S kerogens. The presented correlation is able to predict the thermal maturity, based on Raman spectra, with good accuracy when compared to the reflectance-derived thermal maturity values.