Abstract Oil shale is the most abundant fossil energy resource discovered in Jordan. The objective of this paper is to investigate reservoir characteristics and evaluate the resource potential of the Sultani oil shale deposit in central Jordan, based on their mineral composition, geochemical characteristics and reservoir microstructures.
The samples used for this study were taken from the outcrop in Sultani deposits, South-East of Al-Karak city adjacent to the desert highway. The collected samples were cleaned and made into powder sample, kerogen sample, thin section sample, and ion beam polishing sample. The powder sample was analyzed by X-Ray Diffraction and Organic Carbon Analyzer to clarify the mineral composition and TOC value. The kerogen samples were tested for evaluate the kerogen type and maturity of organic matter. The thin section and ion beam polishing sample were examined by Optical Microscope and Electron Backscattered Diffraction to observe reservoir microstructures. The Sultani shale is formed by various types of minerals, the majority composition is 67.25% calcite and 18.38% quartz, with little apatite, dolomite, and pyrite. The geochemical test shows that: The Kerogen type is dominated by type II1; the Sultani shale can be burned directly and continuously in the air, due to it contains a large amount of organic matter, TOC average value is 14.82%; the value of equivalent vitrinite reflectance is between 0.55% and 0.67%. The Sultani shale is high-quality source rock but with low maturity. Based on Optical Microscope and EBSD result, the micrite (calcite grain size<0.004mm) constitute Sultani shale. Normally, the reservoir should have extremely low porosity, but there is an amount of foraminifer shell fossil which forms the pore structure. The remarkable thing is that the fossil pore have large pore volume and it is poorly connected to its neighbor, the hydrocarbon reserve in the isolated pores.
The Sultani shale is tight reservoir (large pore volume, but poorly connection) with economically attractive resource potential. However, there will be difficult for exploitation, due to it’s specially pore structure. Acid fracturing is feasible technology to connect the isolated fossil pore, thus significantly increase oil production. The Sultani shale can also be burned directly for power generation and get the lime product at the same time, Surface mining is also feasible exploitation patterns.