Proceedings Article | 10 June 2004
Proc. SPIE. 5273, Laser-Induced Damage in Optical Materials: 2003
KEYWORDS: Minerals, Signal attenuation, Laser energy, High power lasers, Laser drilling, Scanning electron microscopy, Thermal analysis, Computed tomography, Chemical analysis, Analytical research
The focus of this paper will be on the analytical techniques used to study laser/rock destruction. High-power COIL, CO<sub>2</sub>, and Nd:YAG lasers were used to drill holes, melt, crack, and vaporize rock samples. Rock types used in the research include: surface sandstones, reservoir sandstones, surface shale, reservoir shale, surface limestone and dolomite, and granite. Physical and chemical properties of the unlased and lased rocks are analyzed. X-Ray Fluorescence (XRF) is used to determine rock chemistry while carbon content is determined by a coulometer. Permeability is determined by the Pressure-Decay Profile Permeameter (PDPK), and Computerized Tomography (CT) imaging is used to calculate the volume of material removed by laser and pixel porosity and density around the lased holes. Thermal properties, such as endothermic and exothermic reactions, clay disassociation, and melting temperatures, are determined using Simultaneous Thermal Analysis (STA). Scanning Electron Microscope with Energy Dispersive Spectrometer (SEM-EDS) is used to map laser-induced fractures and mineralogical transformations. Mineral assemblages, rock texture, and average porosity are determined using petrographic thin sections.
