Abstract: Fluid leakage from a crack or other leakage point and other vibration-generating events in pipes and conduits may be located and analyzed by sensing axial and torsional vibrations and pressure fluctuations created by such events by placing accelerometers and/or strain gauges and pressure sensors on the conduit at selected points. The location of the event may be determined by comparing the travel time of selected pairs of signals such as axial propagated signals as compared with torsional propagated signals as a result in the difference of the acoustic wave speed of axial versus torsional waves. Cross correlation and deconvolution processes are carried out on the measured signals to determine differential signal arrival times at the sensors and to eliminate pipe response signals.

Abstract: Downhole conditions in wellbores such as fluid pressure, temperature and flow conditions during drillstem testing or during wellbore stimulation or fracturing processes are transmitted through sensing and signal conversion circuits to axial or torsional wave vibrators secured to a drillstem or tubing string in the borehole for generating stress wave vibrations in the drillstem or tubing string for transmission to a point at or near the earth's surface. Accelerometers and/or strain gauges are mounted on the stem or tubing at a point near the earth's surface for sensing the torsional, axial or bending vibrations and converting the vibratory signals to signals for receipt and recording and correlated with the signals being transmitted from the borehole. The system includes an axial compression wave generator comprising a solenoid energized oscillator hammer member disposed on a sub which may be interposed in the drillstem.

Abstract: A continuous mining apparatus such as a coal milling or shearing machine includes sensors mounted on the machine frame or on the cutter bits, including an accelerometer and one or more strain gauges, for sensing vibrations and stresses exerted on the cutter bits during operation of the machine. A signal conditioning and amplification circuit provides an audio and/or visual display indicating when the cutter is moving outside of the coal seam and/or is cutting along a cleat or other joint to improve excavation rates while maintaining or lowering stress levels on the cutter bits. The display enables the machine operator to keep from penetrating the roof or floor of the coal seam and to position the cutter to take advantage of natural fracture lines in the seam. The frequency spectrum of the sensor signals is determined to distinguish vibrations caused by bit interaction with the material being cut.

Abstract: Seismic measurements are taken during drilling operations by an array of seismometers placed on the earth's surface about the axis of a drillstring connected to a conventional drillbit and wherein the drillstring has an arrangement of strain gages and accelerometers mounted thereon in such a way as to measure axial and torsional vibrations of the drillstring. Signals indicating vibrations induced by the drillbit or another source and transmitted through the drillstring are compared with signals received by the seismometer array to determine the characteristics of the formation based on measurement of acoustic velocity from direct and reflected transmission of acoustic vibrations through the formation.

Abstract: A drillstem loading and behavior measurement method and system includes spaced apart subs disposed at the upper end of the drillstem and connected to each other and to a power or conventional swivel and having strain gages and accelerometers mounted thereon in such a way as to measure axial loading, axial vibration, torsional loading, torsional vibration and bending modes of the drillstem during operation. Accelerometers are mounted on respective ones of the subs at a distance from each other sufficient to determine vibration waveforms in axial, torsional and bending modes.