Abstract: The present invention describes several techniques for displaying sonic logging data that provide highly reliable, visual quality-control (QC) indicators. One aspect of the present invention is directed to a novel display of sonic logging data corresponding to a slowness frequency analysis (SFA) projection log. One of the benefits of the SFA projection log display of the present invention is that the format of the information displayed may be used to visually confirm the accuracy/inaccuracy of the processed sonic logging data over selected depth intervals. The SFA projection log display may also be used to visually identify any potential problematic or inconsistent portions of the processed sonic logging information. An overlay of estimated wave slowness information may also be displayed onto the SFA log display in a manner which enables an observer of the SFA log display to visually assess the relative accuracy of the estimated wave slowness information over selected depth intervals.

Abstract: A method for determining properties of an earth formation surrounding an earth borehole that involves: providing a logging device moveable through the borehole; transmitting sonic energy into the formation; receiving sonic energy that has traveled through the formation; producing signals representative of the received sonic energy; determining whether the formation is anisotropic; determining whether the formation is inhomogeneous; and outputting a characterization of the formation as one of the following types: isotropic/homogeneous, anisotropic/homogeneous, isotropic/inhomogeneous, and anisotropic/inhomogeneous.

Abstract: A method for determining properties of an earth formation surrounding an earth borehole that involves: providing a logging device moveable through the borehole; transmitting sonic energy into the formation; receiving sonic energy that has traveled through the formation; producing signals representative of the received sonic energy; determining whether the formation is anisotropic; determining whether the formation is inhomogeneous; and outputting a characterization of the formation as one of the following types: isotropic/homogeneous, anisotropic/homogeneous, isotropic/inhomogeneous, and anisotropic/inhomogeneous.

Abstract: The present invention is directed to sonic logging while drilling. A transmitter and at least one receiver are mounted on a drill collar for performing sonic investigations of the formation traversing a borehole. It has been discovered that a drill collar has a natural stop band or notch where acoustic energy propagating in this frequency range is severely attenuated. Thus, to reduce drill collar acoustic coupling, the transmitter is operated within this natural stop band of the drill collar. An imperforate stop band filter is also included between the transmitter and receiver to amplify the natural stop band. The transmitter is mounted transvere to the longitudinal axis of the drill collar, and is preferably mounted within means that reduce drill collar acoustic coupling.

Abstract: The present invention is directed to sonic logging while drilling. A transmitter and at least one receiver are mounted on a drill collar for performing sonic investigations of the formation traversed by a borehole. It has been discovered that a drill collar has a natural stop band or notch where acoustic energy propagating in this frequency range is severely attenuated. Thus, to reduce drill collar acoustic coupling, the transmitter is operated within this natural stop band of the drill collar. An imperforate stop band filter is also included between the transmitter and receiver to enhance the natural stop band. The transmitter is mounted transverse to the longitudinal axis of the drill collar, and is preferably mounted within means that reduce drill collar acoustic coupling.

Abstract: A method and apparatus for determining the setting time of a cement slurry. An acoustic shear wave signal is generated and introduced at a first location in the slurry. The signal is monitored at a second location for direct transmission of the shear wave signal. The time of first detection is determined at the second location which is taken as the setting time of the slurry.