In the past 15 years, high power fiber laser costs have dropped by 100X+ with modular, solid state construction for rugged field transportation. However, long distance transmission of high power lasers was believed to be impossible due to physics limitations known as Stimulated Brillouin Scattering (SBS) and other nonlinear effects.
Stimulated Brillouin Scattering (SBS) is a “physics effect” that chokes off the transmission of high power laser photons in a fiber optic cable by reflecting the energy backwards to catastrophically destroy both the fiber optic cable and laser source. In short, photons and acoustic phonons interact in a vicious cycle that gets exponentially worse with increasing power and distance.
With advanced physics simulations and experimental capabilities, Foro Energy developed a solution where the fiber optic cable, laser source, and combined system are simultaneously engineered to eliminate the onset of SBS even at high laser power levels and long distances.
Another important innovation is a fiber connector built to withstand the high temperature and pressure in a deep well—without requiring the flowing-water cooling normally needed at 20 kW power levels, which is impractical at the bottom of a well. The output port is mounted within the drill bit so the laser light heats the rock just beneath the drill.
A portable oil-drilling setup includes a 20 kW fiber laser and a low-loss fiber-optic cable. The high-power 1070 nm light is delivered down the well where it fractures rock, allowing a low-power mechanical drill to remove the rock. The process potentially cuts the required power for drilling by nearly 90%.
Foro Energy’s proprietary technology overcomes these and other limitations to allow “world first” transmission of:
- High power, by overcoming SBS
- Over long distances, by overcoming SBS
- With low loss, through a proprietary fiber optic specification
- In downhole environments, through a proprietary cabling package
Over the past decade, advancements in fiber laser technology have increased power availability from less than 1 kW to greater than 50 kW.
Fiber laser costs have dropped from over $1,000/W to less than $50/W in just 15 years.
This article is a follow upfrom a 2012 nextbigfuture article on laser enhanced drilling.
Foro Energy's laser-assisted drill bits have the potential to be up to 10 times more economical than conventional hard-rock drilling technologies, making them an effective way to access the U.S. energy resources currently locked under hard rock formations.
Conventional methods to drill, workover, and complete energy wells include mechanical cutting/grinding, explosives, harsh chemicals, and high pressures.
- High power lasers enable fundamentally new performance capabilities.
- Precision: High power lasers can be directed with millimeter accuracy.
- Speed: High power lasers can cut and destroy materials extremely rapidly.
- Safety: High power lasers can be controlled at the speed of light.
Conventional mechanical drill bits cut softer rocks with stresses created by rotating a cutting surface with high weight-on-bit (WOB). Unfortunately, ultra-hard (i.e. high compressive strength) rocks inherently do not yield efficiently to even the most advanced mechanical cutters. The resulting slow drilling and short bit lifetimes result in poor performance and high expense.
Foro Energy developed a process that uses the laser to destroy rock and conventional mechanical bit components to remove the rock. This laser-mechanical drilling process enables
- Step change in drilling rate (2-4x)
- Extremely low WOB (less than 1000 lbs)
- Extremely low torque (less than 300 ft-lbs)
- Longer bit life
- Lower drilling cost per foot
Here is a 2012 presentation on Foro energy laser drilling
SOURCES - Foro Energy, Swiss Photonics, Arpa-E