The US Department of Energy’s Advanced Research Projects Agency – Energy (ARPA-E) has provided funding to Foro Energy to develop inexpensive, high-powered lasers that may be able to tear through rock to drill for oil. This would eliminate the need to bore through the Earth using giant metal drills in the quest for resources. Using lasers would also provide a far greener alternative.
In November, Foro announced that its test system sent a beam from a 2-kilowatt commercial laser through 1.5 kilometers of optical fiber. Borehole drilling trials are scheduled to begin in 2013.
Mechanical drills have been successful in drilling through sandstone and soft rocks to reach petroleum reserves, but these drills don’t manage granite and basalt well and wear out quickly when these rocks are encountered. However, it is basalt and granite that generally contain the best sources of geothermal energy. Foro’s laser beam can compete with mechanical drills by heating rock surfaces so quickly that the thermal shock fractures the upper few millimeters, leaving a top layer the drill can scrape away with very little effort.
According to Foro’s calculations, the laser might increase drilling rates by up to a factor of 10.
Skeptics say it will take more than a flashy prototype to demonstrate the efficacy of the technology. The bottom of a borehole is a brutal environment, and the optics will have to deliver the beam directly to the rock. If the beam is slightly off and hits fluid instead, the fluid will heat and the rock will not be destroyed.
The use of geothermal energy for drilling has not been widely adopted –mainly due to cost. In order for the method to become mainstream, Foro will have to demonstrate its technology can handle the intense work of punching hundreds of holes through very hard rock successfully for long periods of time.
At the very least, Foro’s lasers might be able to be used in place of explosives to create holds in the steel casings of gas and oil wells.
