Evaluation of High Power Ytterbium Fiber Lasers for Rock Cutting and Removal Applications

摘要

Since 1997, GTI has been investigating the applicationof high-power laser energy to several rock lithologiesfor oil and gas well construction and completion.Beginning in 2003, GTI advanced its laser/ rockcutting research by performing additional rock cuttingtests with a 5 kW ytterbium-doped multi-clad fiberlaser.Over the past two years, commercially available fiberlasers have increased in power from several watts tokilowatts. They are now capable of efficientlydelivering requisite power via fiber optics and haverapidly evolved into a leading candidate for on-siteapplications including hard rock mining, tunneling,pavement cuttings and rock drilling. When comparedto conventional industrial lasers, fiber lasers offer up toan order of magnitude greater wall plug efficiency,better beam quality, increased mobility due to theirconsiderably smaller footprint and predictedmaintenance-free operations over their lifetime.This paper explores the use of fiber lasers as analternative means to conventional rock cuttingtechniques that could offer greater cutting efficiencies,quality control, and economic returns. A series of testswere performed on sandstone at atmosphericconditions to determine the minimum energy requiredto remove rock material. Laser parameters includingpower level were optimized. Rock removal efficiencyof fiber laser was compared with other high powerlasers employed for similar research.