Geochemistry and Organic Petrography of Jordanian Sultani Oil Shale

Abstract

The Sultani oil shale (OS) deposit is considered as a major fossil fuel source in Jordan. Applying various petrographic and geochemical techniques, this paper aims to study the Sultani OS geochemical and organic petrographic features. Results show that Sultani OS is a bituminous limestone consisting of very fine-grained matrix with rippled micro-laminated texture and muddy material of cryptocrystalline micrite. The rock is rich in Cretaceous microfossil shells filled in organic matter (OM). The filling OM is bitumen of the migrabitumen type. The OM content reaches up to 17 wt.% with high oil-yielding capacity (up to 12 wt.%). High TOC values suggest that the Sultani OS has a very good source rock potential. Organic petrography shows low OM maturity level and reveals two varieties of vitrinite, namely primary and oxidized vitrinite. The latter is derived from terrestrial plant tissues. Additionally, liptinite macerals including alginite and to a lesser extent cutinite, also participate. Various diagenetic features such as pyrite replacement and bitumen thermal alteration have been recorded. Results suggest that Sultani OS is a marinite formed under marine conditions with limited contribution of terrestrial OM input.