The direct-push permeameter (DPP) is a promising approach for obtaining high-resolution information about vertical variations in hydraulic conductivity (K) in shallow unconsolidated settings. This small-diameter tool, which consists of a short screened section with a pair of transducers inset in the tool near the screen, is pushed into the subsurface to a depth at which a K estimate is desired. A short hydraulic test is then performed by injecting water through the screen at a constant rate (less than 4 L/min) while pressure changes are monitored at the transducer locations. Hydraulic conductivity is calculated using the injection rate and the pressure changes in simple expressions based on Darcy's Law. In units of moderate or higher hydraulic conductivity (more than 1 m/d), testing at a single level can be completed within 10 to 15 min. Two major advantages of the method are its speed and the insensitivity of the K estimates to the zone of compaction created by tool advancement. The potential of the approach has been assessed at two extensively studied sites in the United States and Germany over a K range commonly faced in practical field investigations (0.02 to 500 m/d). The results of this assessment demonstrate that the DPP can provide high-resolution K estimates that are in good agreement with estimates obtained through other means.
Conventional hydrothermal geothermal wells with a depth of around 3000 m and temperatures of 340 °C can yield from 4 up to 10 MW e. Recent studies have proven that productivity might be increased by a factor of 10, if fluids from supercritical resources had been extracted (Friðleifsson et al. 2005, 2014a, b). This is due to the increased enthalpy, lower viscosity, and density of supercritical fluids that allow for much higher flow rates. The longevity of a geothermal well drilled into the supercritical resource depends significantly on the appropriate drilling and well completion technology. Deep and hightemperature drilling projects in countries such as Iceland,
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