Evaluating hydrocarbon source rock for unconventional shale oil play from seismic and well log data; Kingak Shale, North Slope, Alaska

It has been proposed that Acoustic impedance (AI) responses can be used to estimate total organic carbon (TOC) within thick, clay rich shale. The purpose of this work is to evaluate the effectiveness of the AI inversion technique, and establish a methodology that can be applied to other basins. The Kingak Formation (lower Jurassic to early Cretaceous), located on the North Slope of Alaska, has been extensively evaluated for its unconventional potential. The Kingak is shale and is known to have greater than 30 percent clay. Because clay has ductile properties it makes it difficult to stimulate a well through hydraulic fracturing. This AI inversion technique was tested by utilizing synthetic seismograms to create an AI curve generated using The KINGDOM Software©. The synthetic seismograms were used to ensure a well log to seismic match. The synthetic seismograms also created an AI curve along the well. From these synthetic seismograms the AI value was compared to TOC values. It was from this comparison that a trend was observed that did not match the predicted trend. I believe the discrepancy observed was due to the sampling method. Based on this observation, I conclude that the method of tracking TOC with AI responses requires extremely controlled sampling methods; therefore it is not a beneficial method of revisiting old data sets in hopes of identifying new prospects.