Composition of oils produced during an echoing, in-situ combustion of a Utah tar sand

The Laramie Energy Technology Center (DOE) has completed its second in-situ combustion experiment (TS-2C), which was carried out in the Northwest Asphalt Ridge tar sand deposit near Vernal, Utah. During the experiment (183 days) 92 m3 (580 barrels) of oil was produced, 25% of the original oil in place. The in-situ process utilized is best described as a series of reverse- and forward-combustion phases or echoes traversing the 405 m2 (0.1 acre) pattern. Several of the chemical and physical properties of the oil produced are significantly altered with respect to the original bitumen. These include pour point, specific gravity, average molecular weight, wax and nickel content, and the percentage of residue boiling at >538 °C (1000 °F). These and other changes effected on the bitumen during this experiment result in a product oil that closely resembles a heavy fuel oil.