Abstract: Methods and devices for obtaining well log data with reduced coherent noise are provided. One such method may include placing a downhole tool into a well to obtain a set of unfiltered well log data that includes individual measurements obtained at various azimuthal angles within the well. Some of the unfiltered well log data may represent eccentered well log data obtained while the downhole tool is eccentered in the well. The individual measurements of the eccentered well log data may have delays that vary as a function of the azimuthal angle at which they were obtained. By comparing the measurements of the eccentered well log data, a common pattern independent of delay, representing coherent noise, may be identified. The common pattern may be subtracted from the well log data to produce filtered well log data that is less noisy than the unfiltered well log data.

Abstract: System and methods of generating calibrated downhole images of a subterranean formation (110) surrounding a wellbore (105). The method involves measuring open hole and cased hole measurements with a downhole tool (132); determining (698) open hole parameters (e.g., Z90) from the cased hole parameters, known parameters and the open hole measurements; and generating (699) downhole outputs from the determined open hole parameters.

Abstract: Surface equipment of a cement analysis system (CAS) estimates a first drilling fluid slowness (FSLO) and a first drilling fluid acoustic impedance (ZMUD) based on a type and density of wellbore drilling fluid. A second FSLO is estimated based on a thickness and diameter of wellbore casing and transit time for energy emitted by a downhole tool to travel to and from the casing. An FSLO graphical interface is generated based on the first and second FSLO. A second ZMUD is estimated based on the drilling fluid type and density and one of the first and second FSLO selected utilizing the FSLO graphical interface. A ZMUD graphical interface is generated based on the first and second ZMUD. The downhole tool then obtains log data utilizing at least one parameter selected utilizing the ZMUD graphical interface. The log data includes a final ZMUD measured with respect to wellbore depth.

Abstract: Systems, tools and techniques for measuring downhole parameters are provided. The techniques involve providing a downhole tool with a sensing apparatus. The sensing apparatus has at least one source positionable about the downhole tool, at least one sensor electrode positionable about a front face of the downhole tool for measuring electrical signals from the source, and a raised insulating cover positionable along the front face of the downhole tool for defining at least one contact surface. The raised insulating cover extends over at least a portion of the sensor electrode whereby the sensor electrode is positionable adjacent to the subterranean formation for electrically coupling thereto without direct contact therewith.

Abstract: A system and method for imaging properties of subterranean formations in a wellbore is provided. The system comprises a formation sensor for collecting currents injected into the subterranean formations, the formation sensor positionable on a downhole tool deployable into the wellbore. The system comprises a controller for controlling the formation sensor and a formation imaging unit. The formation imaging unit comprises a current management unit for collecting data from the currents injected into the subterranean formations, the currents having at least two different frequencies. The formation imaging unit comprises a drilling mud data unit for determining at least one drilling mud parameter, a formation data unit for determining at least one formation parameter from the collected data, and an inversion unit for determining at least one formation property by inverting the at least one formation parameter.

Abstract: The disclosure is concerned with a tool and method for imaging a formation through a substantially non-conductive medium. The tool includes one or more injection electrodes for injecting current through the substantially non-conductive medium and into the formation. The tool further includes one or more return electrodes for receiving current from the substantially non-conductive medium, the formation, or both. The tool also includes circuitry for determining a complex impedance based on the received current, determining a phase angle of the complex impedance, and determining a component of the complex impedance that is orthogonal to the phase angle.

Abstract: An acoustic logging tool emits a wideband acoustic pulse toward an inside surface of a borehole casing and an acoustic response is received. The acoustic response is analyzed at one or more higher order harmonics of the thickness mode resonance of the casing to determine the acoustic impedance of the material behind the casing.

Abstract: The present disclosure provides an apparatus and method for measuring electrical properties of an underground formation surrounding a borehole. The apparatus preferably comprises a downhole tool positionable in the borehole, a sensor pad positionable on the downhole tool, and a plurality of electrodes mounted on the sensor pad and configured to face a wall of the borehole. The apparatus further comprises an insulating layer extending over at least a portion of the plurality of electrodes facing the wall of the borehole.

Abstract: Surface equipment of a cement analysis system (CAS) estimates a first drilling fluid slowness (FSLO) and a first drilling fluid acoustic impedance (ZMUD) based on a type and density of wellbore drilling fluid. A second FSLO is estimated based on a thickness and diameter of wellbore casing and transit time for energy emitted by a downhole tool to travel to and from the casing. An FSLO graphical interface is generated based on the first and second FSLO. A second ZMUD is estimated based on the drilling fluid type and density and one of the first and second FSLO selected utilizing the FSLO graphical interface. A ZMUD graphical interface is generated based on the first and second ZMUD. The downhole tool then obtains log data utilizing at least one parameter selected utilizing the ZMUD graphical interface. The log data includes a final ZMUD measured with respect to wellbore depth.

Abstract: The disclosure is concerned with a tool and method for imaging a formation through a substantially non-conductive medium. The tool includes one or more injection electrodes for injecting current through the substantially non-conductive medium and into the formation. The tool further includes one or more return electrodes for receiving current from the substantially non-conductive medium, the formation, or both. The tool also includes circuitry for determining a complex impedance based on the received current, determining a phase angle of the complex impedance, and determining a component of the complex impedance that is orthogonal to the phase angle.

Abstract: The disclosure is concerned with a tool and method for imaging a formation through a substantially non-conductive medium. The tool includes one or more injection electrodes for injecting current through the substantially non-conductive medium and into the formation. The tool further includes one or more return electrodes for receiving current from the substantially non-conductive medium, the formation, or both. The tool also includes circuitry for determining a complex impedance based on the received current, determining a phase angle of the complex impedance, and determining a component of the complex impedance that is orthogonal to the phase angle.

Abstract: Methods and devices for obtaining well log data with reduced coherent noise are provided. One such method may include placing a downhole tool into a well to obtain a set of unfiltered well log data that includes individual measurements obtained at various azimuthal angles within the well. Some of the unfiltered well log data may represent eccentered well log data obtained while the downhole tool is eccentered in the well. The individual measurements of the eccentered well log data may have delays that vary as a function of the azimuthal angle at which they were obtained. By comparing the measurements of the eccentered well log data, a common pattern independent of delay, representing coherent noise, may be identified. The common pattern may be subtracted from the well log data to produce filtered well log data that is less noisy than the unfiltered well log data.

Abstract: System and methods of generating calibrated downhole images of a subterranean formation (110) surrounding a wellbore (105). The method involves measuring open hole and cased hole measurements with a downhole tool (132); determining (698) open hole parameters (e.g., Z90) from the cased hole parameters, known parameters and the open hole measurements; and generating (699) downhole outputs from the determined open hole parameters.

Abstract: An acoustic logging tool emits a wideband acoustic pulse toward an inside surface of a borehole casing and an acoustic response is received. The acoustic response is analyzed at one or more higher order harmonics of the thickness mode resonance of the casing to determine the acoustic impedance of the material behind the casing.

Abstract: A system and method for imaging properties of subterranean formations in a wellbore is provided. The system comprises a formation sensor for collecting currents injected into the subterranean formations, the formation sensor positionable on a downhole tool deployable into the wellbore. The system comprises a controller for controlling the formation sensor and a formation imaging unit. The formation imaging unit comprises a current management unit for collecting data from the currents injected into the subterranean formations, the currents having at least two different frequencies. The formation imaging unit comprises a drilling mud data unit for determining at least one drilling mud parameter, a formation data unit for determining at least one formation parameter from the collected data, and an inversion unit for determining at least one formation property by inverting the at least one formation parameter.

Abstract: An acoustic logging tool emits a wideband acoustic pulse toward an inside surface of a borehole casing and an acoustic response is received. The acoustic response is analyzed at one or more higher order harmonics of the thickness mode resonance of the casing to determine the acoustic impedance of the material behind the casing.

Abstract: The present disclosure provides an apparatus and method for measuring electrical properties of an underground formation surrounding a borehole. The apparatus preferably comprises a downhole tool positionable in the borehole, a sensor pad positionable on the downhole tool, and a plurality of electrodes mounted on the sensor pad and configured to face a wall of the borehole. The apparatus further comprises an insulating layer extending over at least a portion of the plurality of electrodes facing the wall of the borehole.

Abstract: Systems, tools and techniques for measuring downhole parameters are provided. The techniques involve providing a downhole tool with a sensing apparatus. The sensing apparatus has at least one source positionable about the downhole tool, at least one sensor electrode positionable about a front face of the downhole tool for measuring electrical signals from the source, and a raised insulating cover positionable along the front face of the downhole tool for defining at least one contact surface. The raised insulating cover extends over at least a portion of the sensor electrode whereby the sensor electrode is positionable adjacent to the subterranean formation for electrically coupling thereto without direct contact therewith.

Abstract: An acoustic logging tool emits a wideband acoustic pulse toward an inside surface of a borehole casing and an acoustic response is received. The acoustic response is analyzed at one or more higher order harmonics of the thickness mode resonance of the casing to determine the acoustic impedance of the material behind the casing.

Abstract: A system and method for determining a downhole parameter is provided. The system has a sensor positionable on a downhole tool. The sensor comprises insulation positionable on a pad of the downhole tool, and return(s) positionable in the insulation, the return(s) adapted to exchange a current with a power source, the return(s) defining a fluid zone. The sensor comprises a mud button positionable within the fluid zone and in the insulation a distance from the return(s), the mud button exchanging current with the return(s). The mud button and the fluid zone are positioned a distance from the formation such that a majority of the current passing between the return(s) and the mud button passes through the downhole fluid whereby the current exchanged with the mud button generates a measurement of the downhole fluid.