Abstract: A technique facilitates seismic exploration by identifying time differences between clocks employed during the seismic exploration. According to an embodiment, a seismic signal is output from a source and has an incident wave and a reflected wave. The seismic signal is received by at least one receiver which outputs data to a control system. The control system is employed to compare a symmetry of the propagation of the incident wave and the reflected wave. The symmetry data is then used to determine a temporal change of the time base of the at least one receiver.

Abstract: A technique facilitates seismic exploration by identifying time differences between clocks employed during the seismic exploration. According to an embodiment, a seismic signal is output from a source and has an incident wave and a reflected wave. The seismic signal is received by at least one receiver which outputs data to a control system. The control system is employed to compare a symmetry of the propagation of the incident wave and the reflected wave. The symmetry data is then used to determine a temporal change of the time base of the at least one receiver.

Abstract: A sensor array is positionable in a wellbore penetrating a subterranean formation. The sensor array includes a plurality of seismic sensors disposable about a perimeter of the wellbore and coupleable to a signal measurer with a configuration to provide three component seismic signal measurement within the wellbore. At least two of the seismic sensors are located at different azimuthal angles relative to one another and oriented tangentially to a longitudinal axis of the wellbore so as to receive tangential components of wellbore seismic signals to the exclusion of longitudinal and radial components of the wellbore seismic signals.

Abstract: A sensor array is positionable in a wellbore penetrating a subterranean formation. The sensor array includes a plurality of seismic sensors disposable about a perimeter of the wellbore and coupleable to a signal measurer with a configuration to provide three component seismic signal measurement within the wellbore. At least two of the seismic sensors are located at different azimuthal angles relative to one another and oriented tangentially to a longitudinal axis of the wellbore so as to receive tangential components of wellbore seismic signals to the exclusion of longitudinal and radial components of the wellbore seismic signals.

Abstract: Methods and apparatus for waveform processing are disclosed. An example method includes estimating a theoretical value of a first input parameter and setting a second input parameter to a known value. The known value is different than an actual value of the second input parameter. The method also includes identifying a frequency band using a processor that minimizes an effect of the second input parameter on a shear slowness inversion value.

Abstract: Methods and apparatus to combine monopole and multipole acoustic logging measurements to determine shear slowness are disclosed. An example method to determine shear slowness of a formation from acoustic logging data disclosed herein comprises determining a plurality of mixed coherence values corresponding to a respective plurality of possible shear slowness values, each mixed coherence value determined by combining a monopole coherence value determined from monopole logging data and a multipole coherence value determined from multipole logging data, the monopole and multipole coherence values each being determined for a particular possible shear slowness value corresponding to the mixed coherence value, and using the particular shear slowness value corresponding to a maximum mixed coherence value in the plurality of mixed coherence values to represent the shear slowness of the formation.

Abstract: Methods and apparatus to combine monopole and multipole acoustic logging measurements to determine shear slowness are disclosed. An example method to determine shear slowness of a formation from acoustic logging data disclosed herein comprises determining a plurality of mixed coherence values corresponding to a respective plurality of possible shear slowness values, each mixed coherence value determined by combining a monopole coherence value determined from monopole logging data and a multipole coherence value determined from multipole logging data, the monopole and multipole coherence values each being determined for a particular possible shear slowness value corresponding to the mixed coherence value, and using the particular shear slowness value corresponding to a maximum mixed coherence value in the plurality of mixed coherence values to represent the shear slowness of the formation.