Abstract: A method and apparatus for measuring parameters of a borehole using an acoustic logging system. By transmitting a high frequency acoustic signal essentially perpendicular to the major axis of a borehole casing using a transducer, the high frequency acoustic signal may produce one or more acoustic echoes. By receiving and analyzing a first acoustic echo from an inner wall of the borehole casing and at least one second acoustic echo from a back wall of the borehole casing, borehole parameters such as the impedance of the casing cement and the thickness of thicker borehole casings, up to and greater than 1 inch, may be determined.

Abstract: Methods and systems for logging a wellbore having a casing are described. Acoustic energy, typically ultrasonic acoustic energy, is used to stimulate reverberation of the casing at a harmonic (for example, the second or third harmonic) of the resonance frequency of the casing. One or more acoustic sensors are used to measure acoustic signals generated by the casing reverberation. Parameters of the casing are calculated based on the measured acoustic signals adjusted by an adjustment factor determined by the particular harmonic. The use of harmonics instead of the fundamental resonance frequency allows wellbores with casings having walls thicker than 0.625 inches to be logged.

Abstract: Methods and systems for logging a wellbore having a casing are described. Acoustic energy, typically ultrasonic acoustic energy, is used to stimulate reverberation of the casing at a harmonic (for example, the second or third harmonic) of the resonance frequency of the casing. One or more acoustic sensors are used to measure acoustic signals generated by the casing reverberation. Parameters of the casing are calculated based on the measured acoustic signals adjusted by an adjustment factor determined by the particular harmonic. The use of harmonics instead of the fundamental resonance frequency allows wellbores with casings having walls thicker than 0.625 inches to be logged.

Abstract: A method and apparatus for normalizing an acoustic wellbore tool by correcting measured sector acoustic signals due to changes in pressure and temperature downhole, the method and apparatus comprising an acoustic wellbore tool having at least one monopole transmitter and monopole receiver, and one or more sector transmitters and receivers disposed along the longitudinal axis of the tool, determining the attenuation values of received monopole and sector acoustic signals, determining a correction ratio using an average sector attenuation value and a theoretical attenuation value, and correcting the sector acoustic signals using the correction ratio.

Abstract: A method and apparatus for normalizing an acoustic wellbore tool by correcting measured sector acoustic signals due to changes in pressure and temperature downhole, the method and apparatus comprising an acoustic wellbore tool having at least one monopole transmitter and monopole receiver, and one or more sector transmitters and receivers disposed along the longitudinal axis of the tool, determining the attenuation values of received monopole and sector acoustic signals, determining a correction ratio using an average sector attenuation value and a theoretical attenuation value, and correcting the sector acoustic signals using the correction ratio.

Abstract: A method and apparatus for measuring parameters of a borehole using an acoustic logging system. By transmitting a high frequency acoustic signal essentially perpendicular to the major axis of a borehole casing using a transducer, the high frequency acoustic signal may produce one or more acoustic echoes. By receiving and analyzing a first acoustic echo from an inner wall of the borehole casing and at least one second acoustic echo from a back wall of the borehole casing, borehole parameters such as the impedance of the casing cement and the thickness of thicker borehole casings, up to and greater than 1 inch, may be determined.

Abstract: An acoustic borehole logging system for generation and detection of multipole modes used to determine elastic properties of earth formations characterized as inhomogeneous anisotropic solids. The system concurrently generates and senses monopole, dipole, quadrupole and any higher order pole in the borehole/formation system in order to characterize the elastic properties and stress state of material penetrated by the borehole. Multipole modes of all orders are induced simultaneously without the need for separate transmitter and receiver systems. Performance of the logging system is not compromised due to eccentering of the axis of the tool in the borehole, tool tilt with respect to the axis of the borehole, or mismatch of response sensitivity of multiple receivers within the tool.

Abstract: An acoustic borehole logging system for generation and detection of multipole modes used to determine elastic properties of earth formations characterized as inhomogeneous anisotropic solids. The system concurrently generates and senses monopole, dipole, quadrupole and any higher order pole in the borehole/formation system in order to characterize the elastic properties and stress state of material penetrated by the borehole. Multipole modes of all orders are induced simultaneously without the need for separate transmitter and receiver systems. Performance of the logging system is not compromised due to eccentering of the axis of the tool in the borehole, tool tilt with respect to the axis of the borehole, or mismatch of response sensitivity of multiple receivers within the tool.

Abstract: An acoustic borehole logging system for generation and detection of multipole modes used to determine elastic properties of earth formations characterized as inhomogeneous anisotropic solids. The system concurrently generates and senses monopole, dipole, quadrupole and any higher order pole in the borehole/formation system in order to characterize the elastic properties and stress state of material penetrated by the borehole. Multipole modes of all orders are induced simultaneously without the need for separate transmitter and receiver systems. Performance of the logging system is not compromised due to eccentering of the axis of the tool in the borehole, tool tilt with respect to the axis of the borehole, or mismatch of response sensitivity of multiple receivers within the tool.

Abstract: An acoustic borehole logging system for generation and detection of multipole modes used to determine elastic properties of earth formations characterized as inhomogeneous anisotropic solids. The system concurrently generates and senses monopole, dipole, quadrupole and any higher order pole in the borehole/formation system in order to characterize the elastic properties and stress state of material penetrated by the borehole. Multipole modes of all orders are induced simultaneously without the need for separate transmitter and receiver systems. Performance of the logging system is not compromised due to eccentering of the axis of the tool in the borehole, tool tilt with respect to the axis of the borehole, or mismatch of response sensitivity of multiple receivers within the tool.

Abstract: An acoustic borehole logging system for generation and detection of multipole modes used to determine elastic properties of earth formations characterized as inhomogeneous anisotropic solids. The system concurrently generates and senses monopole, dipole, quadrupole and any higher order pole in the borehole/formation system in order to characterize the elastic properties and stress state of material penetrated by the borehole. Multipole modes of all orders are induced simultaneously without the need for separate transmitter and receiver systems. Performance of the logging system is not compromised due to eccentering of the axis of the tool in the borehole, tool tilt with respect to the axis of the borehole, or mismatch of response sensitivity of multiple receivers within the tool.

Abstract: An acoustic logging system with a borehole tool comprising a transmitter assembly and an axially spaced receiver assembly. The transmitter and receiver assemblies are optionally rotatable with respect to each other, depending upon the embodiment of the logging system. The logging system is designed to measure, among other parameters, the velocity (or slowness) and amplitude of shear wave energy induced by the transmitter assembly within formation penetrated by the borehole. These parameters are extracted from full wave acoustic data responses of receiver elements comprising the receiver assembly, and are measured as a function of azimuth around the borehole. These parameters are subsequently used to determine anisotropic properties of the formation, such as the azimuthal direction of formation fracturing with respect to the well borehole. Optional rotation of the transmitter and receiver assemblies minimizes adverse effects of maintaining calibration and balance of multiple transmitters and receivers.

Abstract: A production logging tool is provided for use within a well to directly measure a velocity profile of a multiphase fluid flow within a cross-section of a well. The production logging tool includes a tool housing from which a plurality of arms are radially extensible. The plurality of arms are rotatably mounted to the tool housing for rotating around a tool axis extending longitudinally through the tool housing. At least one Doppler flow sensor is fixedly mounted to one of the plurality of arms for moving with the arm to dispose the Doppler flow sensor within different localized regions within a cross-section of the well. The localized regions of the cross-section are located at different radial distances from and at different angular displacements around the tool axis of the tool housing, at points distal from the tool axis.

Abstract: A sonic well logging tool radially measures circumferential cement conditions longitudinally along a well casing. Sonic signals are transmitted from a plurality of angularly displaced transmitter-transducers, through a borehole fluid, down a longitudinally extending sector of the well casing, and then through the borehole fluid to a plurality of angularly displaced receiver-transducers, which are distally disposed from the transmitter-transducers.

Abstract: A caliper tool for measuring internal dimensions of an enclosure with the tool including a housing of a size to fit within the disclosure and several feeler arms attached in a rotatable fashion to the tool housing with each feeler arm extending outwardly from the tool housing to engage the interior surface of the enclosure. A control apparatus is provided and attached to the tool housing for controlling the location of the tool housing within the enclosure. A mechanical apparatus contained within the tool housing is attached to the feeler arms and provides a translation of the rotational positions of the feeler arms into linearly displaced positions. Magnetostrictive linear displacement transducers are connected to the mechanical means to convert the linear displacement positions into electrical signals representing these positions.