THERMAL CHARACTERIZATION OF GBETIOKUN OIL SHALE VIA ROCK-EVAL PYROLYSIS AND THERMOGRAVIMETRIC ANALYSIS

Abstract

The pyrolysis characteristics of Gbetiokun oil shale were investigated with rock-eval pyrolysis and thermogravimetry analysis (TGA). The Rock-Eval pyrolysis outlined the hydrocarbon potential of the oil shale sample via total organic carbon (TOC) value,hydrogen Index (HI) and production index (PI). The TGA was investigated at different heating rates of 10, 20 and 30 oC/min in the temperature range of 29-950oC (Fig. 1). From the Rock-eval pyrolysis, it was deduced that the oil shale sample has a total organic carbon (TOC) value of 0.51wt% more than 0.5wt% which is the minimum standard required for the generation of hydrocarbon. The hydrogen index (HI) value of 208 mg HC/gTOC falls within the range of 150-300 mg HC/gTOC indicating that the sample is oil and gas prone. While PI value for the sample is 0.05 which is less 0.1 signifying that the organic matter is immature.The TGA shows the main stage of mass loss at temperature range of 200-620oC and higher corresponding to the release of oil and gas, further weight loss was due to decomposition of carbonate. It was also observed that increasing the heating rate shifted the weight loss to higher temperatures. It can be concluded that Gbetiokun oil shale has high potential to generate hydrogen and both Rock-Eval pyrolysis and TGA show that the sample is oil and gas prone.