?Brian C. Gahan is a man on a mission. As president of Laser Rock Technologies LLC of Cary, Illinois, he plans to develop high-power, laser-cutting applications for rock, concrete and other earth materials, and transition the technology from lab to commercial field applications.


This alternative method to mechanical cutting techniques has been developed over the past decade, primarily for subsurface well construction and completion in oil and gas wells, Gahan says. “Distinct advantages have been identified and tested, offering revolutionary changes in how the industry has mechanically drilled and perforated rock for over 100 years.”


Laser Rock is working with an unnamed major oilfield-technology and -service company and Oxford, Massachusetts-based IPG Photonics Corp., a laser manufacturer, to develop several commercial field applications. Fiber laser technology is key to allowing successful field applications in industries that cut, drill and ablate rock and concrete, he says.


Laser Rock is also developing a downhole application for geothermal well construction. Applications in the oil and gas industry could include perforation, remediation or recompletion, slotted liners and screens, casing windows, multilaterals, casing cutting, offshore platform abandonment and more.


He visualizes the laser as a multi-purpose tool through development of job-specific attachments, similar in concept to home construction tools that have saw, drill and sander attachments for a single platform.
To many in the laser industry, fiber lasers are now a serious alternative to solid-state and CO2 lasers for industrial material-processing applications. During the past two years, commercially available fiber lasers have increased in power from several watts to thousands.


“They are now capable of efficiently delivering the requisite power via fiber optics to targets downhole, and have rapidly evolved into the leading candidate for on-site applications in well construction and completion,” he says.


When compared with conventional industrial lasers, fiber lasers offer greater wall-plug efficiency, better beam quality, increased mobility due to their considerably smaller footprint, and essentially maintenance-free operations during their lifetime. Their use as an alternative method to conventional explosive charges could reduce or eliminate perforation damage and significantly boost production rates, cumulative production and overall economic returns, according to Gahan and co-authors Samih Batarseh, Bhargav Sharma and Sherif Gowelly in a paper published a few years ago.


“Fiber lasers present a number of advantages over other industrial lasers. They have the advanced realization of high-power laser applications for well perforations and other well construction and completion methods. Many of the deployable characteristics required by the industry for a commercially successful system have been met in this most recent technical breakthrough,” the co-authors report.


Earlier work performed by the group explored the use of high-power laser energy as a non-damaging alternative to conventional explosive perforation methods. Several variables were investigated to determine the technical feasibility of laser perforation with a 5.34-kilowatt Ytterbium-doped multiclad fiber laser exposed to rock, cement and steel samples.


The fiber laser was capable of penetrating these materials under a variety of conditions, to an appropriate depth, and with reasonable energy requirements. It was determined that fiber lasers are capable of cutting rock without causing damage to flow properties. Furthermore, the laser perforation resulted in permeability improvements on the exposed rock surface.


Tests were also performed to determine the effect of downhole pressure conditions on the application. A sophisticated tri-axial cell was designed and tested using Berea sandstone, limestone and clad-core samples, lasered under various combinations of confining, axial and pore pressures. Clad-core samples consisted of steel cemented to rock in an effort to represent material penetrated in a cased hole. The results proved the viability of the laser’s effectiveness downhole, and will assist in the development of downhole, prototype-laser tools.


The key to field applications is centered on the fiber laser technology. Although fiber lasers have been available since the early days of laser technology, their role was limited to low-power, optical-signal amplifiers in the telecommunications industry. Recent and rapid advances in fiber-laser development have made them a commercially viable alternative to competing solid-state and CO2 lasers. They have also been successfully used in the battlefield as part of the U.S Army’s Zeus Humvee to destroy landmines and other explosive devices from a safe distance.


Gahan says other industries with potential applications include hard-rock and ore mining, military, pipeline, space, construction and demolition.

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