Rendering of a SHA gasification plant. Click to enlarge.

The process begins by drilling into the body of oil shale and locating a processing inlet conduit within the hole. An effluent conduit is anchored around the opening of the hole at the ground surface. Pressurized air is introduced to an above-ground combustor, superheated and directed underground into the oil shale through the inlet conduit.

As the superheated air (SHA) travels down a borehole, it interacts with the kerogen in the oil shale and brings hydrocarbons to the surface in the form of hot gases. The gases are then condensed to yield light hydrocarbon liquids and gases. The process achieves a controlled and relatively quick production of product.

Heat from the SHA creates a radiant heat process throughout the length of the processing gas inlet conduit, causing a non-burning thermal energy front in the oil shale surrounding the hole in a predictable radius. The high temperatures and correct pressures cause the oil bearing material to gasify. The porosity of the marlstone allows the gaseous hydrocarbon products to be withdrawn as an effluent gas into the effluent gas conduit.

This resulting gas is transferred from the effluent gas conduit into a condenser where it is allowed to expand and cool and produce liquid and gas hydrocarbon products. A portion of the gas produced is recycled to the combustor to blend with other recycled feedstocks and provide combustible material for continuous fueling within the combustor. This self-perpetuating feedstock feature reduces the cost of product substantially.

The system is intended to be able to recover gas and oil from an oil shale formation at potentially any depth. Initial test results have suggested the process could be economical for recovering hydrocarbon products from all regions of an oil shale formation.

The exploration agreement with a subsidiary of Anadarko Petroleum Corporation in Wyoming covers approximately 160 acres near Rock Springs on a Union Pacific Railroad section upon which GSI plans to carry out its proof-of-concept test under stringent environmental guidelines. The Colorado opportunity provides GSI access to approximately 500 acres of private, oil-shale-rich land in the Piceance Basin, with the potential—based upon core analysis and geologic data—to recover approximately 700 million barrels of oil, or oil equivalents, in the near term.

GSI believes results should be known within the next 24 months. The company is also evaluating an additional 2,500 acres of oil shale mineral rights in the same area of Colorado and is in the process of investigating how many barrels of oil are in place.

Resources

• Secure Fuels from Domestic Resources: The Continuing Evolution of America’s Oil Shale and Tar Sands Industries (US Department of Energy, Office of Petroleum Reserves, Office of Naval Petroleum and Oil Shale Reserves; June 2007)