Abstract: In the apparatus and method of the invention, acoustic energy is propagated in two slightly differing, or offset, circumferential paths in such a way as to interact with the formation under investigation. The propagating energy is detected and the resulting waveforms are compared using semblance. The waveforms corresponding to the respective paths will be quite similar provided that the length of the paths are equal and that there are no fractures or other similar anomalies between the source and receiver. The waveforms for the respective paths will be quite dissimilar, however, if a fracture or similar anomaly does lie between the source and receiver for the respective paths. The semblance may be displayed in log format.

Abstract: Methods and apparatus are provided for thermally compensating pressure determinations of pressure gauges through the use of a fast responding thermal device which is attached to the gauge and a dynamic model of the pressure gauge resonator which assumes that the temperature is not uniform throughout the resonator when temperature transients are present. The pressure gauge is subjected to known temperature and pressure conditions so that the parameters of a dynamic thermal model of the resonator may be determined, as well as a frequency and temperature to pressure mapping. The gauge may then be used to make measurements and provides a frequency output. The thermal device provides temperature readings. The temperature readings are input into a dynamic system using the dynamic thermal model to provide a correction to the frequency output of the pressure gauge such that the corrected frequency may be input into the frequency and temperature to pressure mapping to provide the thermally corrected pressure reading.