Laser drilling has long been touted as the industry’s next great leap, but Ros Davidson explores whether this futuristic technology is set to remain just that.
Within just a few years, high-powered lasers may be used for slicing through rock – like a knife through butter – deep underground during commercial oil and gas drilling.
In essence, lasers are an old technology. They derive from the concept of “stimulated emissions” first theorised by Einstein 100 years ago, but were not built in the form that we would recognise today until 1960. Even then, the reception from the scientific and engineering community was that lasers were “a solution looking for a problem.” In the intervening years, much of their development was driven by military applications, perhaps the most famous example being the Reagan-era Star Wars initiative. In this instance, the idea was to use airborne lasers for shooting missiles out of the sky or for destroying military targets on the ground. But with the end of the Cold War, military interest in their use fizzled somewhat.
“It was the classic example of a technology that had been developed that was waiting for a real need,” explains Dr Ramona Graves, speaking with InnovOil by phone. Graves is the foremost US expert on the application of lasers for the oil and gas sector, and a professor and dean of the College of Earth Resource Sciences & Engineering at the Colorado School of Mines. Moreover, Graves believes that these industries have just such a need. The fundamental goal with drilling is, of course, deeper and cheaper – achieved along the way by improving other parameters like accuracy and speed. High-powered lasers, if they can be developed commercially in the way that their backers expect, would be faster, cheaper, more precise and would have a far smaller environmental footprint than even a modern drilling rig.
An underappreciation of advances in the technology – and what these can offer the industry – is still an issue. According to Graves, a high-powered laser will use far less power than a drilling rig. A laser beam is also straight – whereas a drill bit will slip, move around and follow stresses in the earth. Harnessing lasers for oil and gas drilling would be truly revolutionary, and the first fundamental advance since the mechanical rotary-drilling technique, invented in the UK at the end of the Industrial Revolution and long before the dawn of the age of oil and gas. Not surprisingly, there has been intense interest in high-powered lasers for oil and gas applications from major oil and gas producer and oilfield services companies of late.
High in fibre The laser itself would sit above ground at the drilling site, with the beam guided down even the deepest well bore via a fibre-optic cable. The beam, carried underground to the rock interface, would then make contact with the rock, heating it to hundreds of degrees, softening, breaking or even vaporising it. A mechanical drilling bit could then proceed faster, and with greater accuracy and ease. Foro Energy of Texas and Colorado – a company founded by Graves in 2006 – claims that it can deliver multi-kW laser power over many miles of distance for oil and gas or geothermal applications. It has developed a prototype fibre laser – an optical fibre doped with rare earth elements which allow the fibre to be flexible and to produce high output – with Department of Energy [DoE] funding. The company’s design prevents the scattering of the laser as it travels down the fibre-optic cable, and it has also built a fibre connector which can withstand the pressure and temperature in a deep underground well.
One advantage of lasers is that they can easily cut through something as hard as igneous rock, and oil and gas fields can be capped by granite or basalt. With conventional drilling, heavy pressure may be needed to press down on the drill, to proceed through these formations, and the bit can be worn out easily, all of which adds time and expense. With a laser, it should be relatively easy. “The more solid something is, the more [lasers] like it,” says Graves.
Historically, one of the greatest hurdles in deploying laser technology is that it takes a lot of energy to excite light into becoming a laser. When research on lasers for oil and gas applications began in the 1970s, the hydrocarbons produced contained less energy than the laser used to cut or smash the rock. Yet, laser equipment – once the size of a small building – has become much smaller and cheaper. Suitable equipment can be acquired for as little as US$200,000 – a tenth of the cost of even a few years ago. More specifically, Foro Energy says that in the past 15 years alone, the cost of its particular high-power fibre lasers have dropped by more than 100-fold – even with addition of modular and ruggedised elements which allows for field transportation. Foro has partnered with Chevron and the DoE’s ARPA-E programme, or Advanced Research Projects Agency-Energy.
Muddied outlook Promising though they may be, questions do remain over some elements of laser drilling. In particular, some experts are concerned with how to extract the rock that has become molten or pulverised to the surface. Compressed air, or gases – such as helium or nitrogen – could be used but they are more expensive and may not apply to all wells as replacements for traditional drilling mud, says Dr Paul Bommer of the Department of Petroleum and Geosystems Engineering at the University of Texas at Austin. This would require the laser/rock interface to remain undisrupted. “You need an ‘isolated pocket’ where the laser is not being interfered with by the things it hates,” he adds.
Lasers can also be used effectively under water, counters Graves. The Macondo well, and ensuing disaster at Deepwater Horizon, could have been minimised with laser technology sent underwater on robots and used to cut off the flow almost immediately, she notes. In fact, Graves’ point is to emphasise that lasers could be put to work on any rock or solid material encountered in the industry, whether shale, concrete, granite, concrete or metal. Every rock, however, will require a slightly different wavelength of light for the system to perform effectively, she notes. Laser beam delivery can be designed to spall, vaporise or melt the rock, and if there are drill cuttings created, then nitrogen or carbon dioxide are the optimum carrier fluids for removal.
In the oil and gas industry, Graves predicts that high-powered lasers will be in use commercially in about five years’ time, though she laughs and recalls that she said that in 2006 and again in 2011. “The technology is there, the science is there, but the industry has not motivation to develop it,” she says. “What do you do with the trillions of dollars invested in everything from platforms to logging tools?” she posits. “You’d be throwing out so much money.” Be that as it may, the current downturn in oil and gas may help. “You have to get creative to make money,” Graves says. Initially, she suggests that high-powered lasers could most likely be used for smaller jobs – such as cutting a hole in a well to sidetrack, perhaps if a tool is stuck down-hole, for perforating casing, or cutting windows. Indeed, InnovOil would suggest that decommissioning operations in particular, whether removing subsea structures or section milling during plugging and abandonment (P&A), could benefit from the precision and power offered by laser technology. The problem, as ever, is that it is not a technology to which the industry is yet accustomed. In that sense, lasers may still be “a solution looking for a problem” – but the industry has no shortage of the latter. Perhaps it is time this cutting-edge technology was finally put to the cutting edge in earnest.