UPPER CRETACEOUS (TURONIAN-CENOMANIAN) OIL SHALE SOURCE ROCK CHARACTERIZATION THROUGH ORGANIC GEOCHEMISTRY AND PETROLOGY, APPLICATION FOR PALEO-CONDITION RECONSTRUCTION

This study characterized the organic matter composition of the upper cretaceous oil shale from the central Canada to investigate the hydrocarbon potential and the paleo-depositional environment. This work includes 95 samples obtained from two borehole cores from locations along the eastern margin of the Canadian Cretaceous Interior Seaway. The first core is located in southwestern Manitoba proximal to the pale-shoreline position, while the second core is in central part of Saskatchewan located in a deeper part of the paleo-sea compare to the first well.

The result shows that the two groups of samples are immature (mean VR_o=0.38%) and organic-rich (mean TOC=7%) with predominantly liptinite-rich, marine kerogen. There is minor contribution of reworked vitrinite and inertinite macerals. Relatively higher input from land comprising vitrinite macerals was found in samples from core 1 compared to core 2; likely due to its closer proximity to the paleo-shoreline. Accordingly, samples from second core show higher percentages of organic matter as well as S₂ values, which confirm their deeper water depositional settings, better preservation, and possibly lower concentrations of oxygen.

In this work, organic geochemistry and petrography will be integrated with sedimentary observations, and inorganic geochemistry and mineralogy for a more holistic reconstruction of paleo-condition. The generated model is essential to better evaluate the hydrocarbon generation potential of the oil shale and biogenic shale gas play.