PROCEEDINGS, Thirty-Seventh Workshop on Geothermal Reservoir Engineering Stanford University, Stanford, California, January 30 - February 1, 2012 SGP-TR-194 QEMSCAN® (QUANTITATIVE EVALUATION OF MINERALS BY SCANNING ELECTRON MICROSCOPY): CAPABILITY AND APPLICATION TO FRACTURE CHARACTERIZATION IN GEOTHERMAL SYSTEMS 1 1 2 3 3 Bridget Ayling , Peter Rose , Susan Petty , Ezra Zemach and Peter Drakos 1 Energy & Geoscience Institute, The University of Utah, Salt Lake City, UT 84108, USA 2 AltaRock Energy Inc., Seattle, WA 98103, USA 3 Ormat Nevada Inc., Reno, NV 89511, USA
[email protected] elemental distribution, and enables relatively fast data ABSTRACT acquisition (3 cm² can be analyzed in approximately 3 hours). Finer resolutions (down to 2.5 µm) take Fractures are important conduits for fluids in significantly longer, but can be used to provide geothermal systems, and achieving and maintaining additional spatial detail in areas of interest preceding fracture permeability is a fundamental aspect of EGS a low resolution (10 µm) scan. Use of XRD and (Engineered Geothermal System) development. electron microprobe techniques in conjunction with Hydraulic or chemical stimulation techniques are QEMSCAN® data is sometimes needed to distinguish often employed to achieve this. In the case of geothermal alteration minerals with similar chemical chemical stimulation, an understanding of the compositions (smectite clays and chlorite), however minerals present in the fractures themselves is overall the technique appears to have excellent desirable to better design a stimulation effort (i.e. potential for geothermal applications. which chemical to use and how much). Borehole televiewer surveys provide important information 1.0 INTRODUCTION about regional and local stress regimes and fracture characteristics (e.g.