| Abstract |
Economic extraction of geothermal fluids requires the production wells to intersect zones of a high permeability within the porous reservoir rocks. Such permeable zones are often associated with rock fracturing caused by geological faulting. Hence, assessment of faults and their associated fracture zones can be important for delineating the productive parts of a geothermal reservoir.A method for tracing faults and fractures by analysis of lineaments from digital topographic data is described in this paper. The result can be presented as a contour ma of ëfault and fracture densityí (FFD), which measures the total length of lineaments per unit area (unit: , or Two examples of this analysis, from the Te Kopia and Mokai geothermal fields in the Taupo Volcanic Zone (NZ), show that high FFDmapped at the surface can be indicative of high permeability at depth. |