WASHINGTON, DC - A U.S. Department of Energy-funded project has successfully demonstrated the viability of a new technology that could prove to be the key to unlocking America's largest potential source of oil.
If ongoing research continues to confirm the technology's effectiveness, its application offers the potential to dramatically reduce costs and environmental impacts in the extraction of oil from oil shale.
America holds more than three-fourths of the world's estimated 2.6 trillion barrels of oil-in-place of oil shale resources. As much as 1.1 trillion barrels of oil equivalent is believed to be recoverable in the richest single deposit - the Green River formation of Colorado, Utah, and Wyoming. That volume is almost 50 percent greater than the combined proved reserves of conventional oil in the entire Middle East.
The oil price collapse of the early 1980s adversely affected earlier efforts to develop this vast unconventional resource. Expectations of continued high oil prices and national energy security concerns have revived interest in developing the Nation's oil shale resource. A mature oil shale industry producing 3 million barrels per day of oil 30 years from now could provide America with direct and indirect economic benefits of as much as $40 billion per year while pressuring oil prices downward, according to one DOE study.
Oil shale contains a substance called kerogen that occurs in sedimentary rock and is thought to be a precursor to petroleum. Kerogen cannot be extracted like oil that is pumped from a reservoir. The oil shale rock must be heated to a high temperature in a process called retorting, and the liquid that results must be separated and collected, with fine particles removed. The liquid product is then upgraded to a synthetic crude oil that is ready for shipment and refining through the Nation's existing petroleum industry infrastructure.
Previous attempts to develop U.S. oil shale resources on a large, commercial scale were costly, complicated megaprojects that entail mining huge volumes of oil shale and processing the mined shale in large, complex plants to yield an upgradeable liquid. A project managed by DOE's National Energy Technology Laboratory is pursuing a lower-cost, more environmentally benign alternative to the mining megaprojects of the past. Composite Technology Development Inc. (CTD), Lafayette, Colo., is developing a technology that can heat the oil shale in situ, several thousand feet below the surface, separating the kerogen without mining the oil shale rock. If proven viable, the process could extract the petroleum-like liquid and render it mobile enough to be pumped to the surface.
CTD's project goal is to develop downhole cable heaters 2,000-5,000 feet long that can be deployed in oil shale deposits. These cable heaters would provide high power, at preferably high voltages, to heat the oil shale to about 850 degrees Celsius (1,550 degrees Fahrenheit). There are two main challenges associated with developing this technology:
- Producing electrical insulation material that is stable in the subsurface at high temperatures over time.
- Developing a cost-effective manufacturing method to fabricate the heaters.
In the first phase of the project, CTD developed and evaluated high-temperature ceramic-based composite insulation materials that meet the requirements of an in situ oil shale recovery process. Researchers also conducted 2,500 hours of tests of the performance of the new insulation materials in full-power, limited-length cable heater prototypes. The results: much improved insulating qualities that were stable over time when compared with commercially available products.
In the project's second phase, CTD is developing and scaling up a manufacturing process to cost-effectively produce the new-design cable heaters in lengths relevant to an oil shale recovery system.
By eliminating the mining and large-scale processing aspects of oil shale development, such in situ technology could slash its recovery cost by half or more while minimizing disturbance of the land. This bodes well for efforts to develop the world's largest liquid hydrocarbon resource and thus reduce America's dependency on oil imported from unstable regions.