Drilling with the Aid of Lasers
The UK’s New Scientist (Hecht) reported that "Foro Energy, a start-up company in Littleton, CO, has developed what it claims is an inexpensive system of high-powered lasers that can rip through rock,potentially revolutionizing drilling for petroleum as well as geothermal energy.”The article went on to say “mechanical drills can easily grind through soft rocks like sandstone to tap petroleum reserves, but they wear out quickly in hard crystalline rocks such as granite and basalt. … Foro's intense laser beam heats hard rock surfaces so fast that thermal shock fractures the upper few millimeters’, leaving a crumbled layer that a mechanical drill can scrape away quickly andwith little wear." The article reported the development was funded by theUS Department of Energy's research arm, ARPA-E. Borehole drilling trials areplanned for 2013.
Why lasers now? The advent of the fiber laser with its ability to transmit high power along a fiber-optic cable. They have also dropped in price. Fiber laser costs have dropped from over $1000/W to less than $50/W in just 15 years, according to Foro Energy.
In a presentation at a conference in early November (Swiss Photonics), the company presented its drilling process, emphasizing that it “combines high-power laser energy with oil field “dumb” iron to enable drilling of ultra-hard crystalline rocks.” Foro Energy reported system tests with lasers powered up to 20 kW. The laser was threaded down a 1.5-km-long optical fiber with minimal side-effects or power loss. Rock formations the technology is targeting include granite, basalt, dolomite, and quartzite among others.
One significant advantage the company touts is the reduced weight on bit and lower torque for drills using the laser-assist--orders of magnitude less.
More information: ForoEnergy