Abstract: The present invention provides a method for selecting the location of a stimulating well, comprising the steps of conducting a geological study of a field containing a geothermal hydrothermal resource by operating geological useful equipment, determining a maximum horizontal stress line within said field by means of a device, generating a map of existing wells including a plurality of sub-commercial wells within said field relative to said maximum horizontal stress line, measuring a distance between each of said sub-commercial wells and the maximum horizontal stress line, determining that those sub-commercial wells aligned with, or located relatively close to the maximum horizontal stress line are stimulatable, and selecting a location of a stimulating well for stimulating the stimulatable well that is separated less than an anticipated fracture propagating distance from said stimulatable well.

Abstract: The present invention provides a method for selecting the location of a stimulating well, comprising the steps of conducting a geological study of a field containing a geothermal hydrothermal resource by operating geological useful equipment, determining a maximum horizontal stress line within said field by means of a device, generating a map of existing wells including a plurality of sub-commercial wells within said field relative to said maximum horizontal stress line, measuring a distance between each of said sub-commercial wells and the maximum horizontal stress line, determining that those sub-commercial wells aligned with, or located relatively close to the maximum horizontal stress line are stimulatable, and selecting a location of a stimulating well for stimulating the stimulatable well that is separated less than an anticipated fracture propagating distance from said stimulatable well.

Abstract: A source of seismic waves operable within a borehole filled with liquid crises a module supported by a cable. The module includes means to generate a high voltage and to charge a bank of capacitors, and means to connect the capacitors across a pair of electrodes forming a spark gap. The electrodes are immersed in liquid at the same pressure as the borehole liquid and acoustically continuous with it, and are separated by a gap of width between 0.5 and 20 mm. If the gap is greater than about 5 mm, both the electrodes should be covered with insulation except at the positions where the spark is to be formed. The module can operate automatically at considerable depths and at high pressures.

Abstract: An instrument for sensing seismic waves and determining their direction of propagation is operable at considerable depth in a borehole. It comprises a short, stubby sensor module with means to clamp it to the borehole wall and including three accelerometers, and connected by a flexible umbilical cord to a primary module suspended by a cable. The down-hole electronics and the power supply for the clamp means are provided in the primary module. The sensor module has a fundamental resonant frequency about 1 kHz, well above the frequency of the seismic waves it is subjected to, so that the signals from the accelerometers accurately represent those waves.