Abstract: Methods and systems for determining petrophysical parameters of a formation are provided. In one embodiment, a method includes acquiring formation data with a borehole imaging tool deployed in a well penetrating a formation and acquiring additional formation data with a dielectric logging tool deployed in the well. The method also includes calibrating the formation data acquired with the borehole imaging tool based on the additional formation data acquired with the dielectric logging tool. The calibrated formation data can then be used in determining a petrophysical parameter of the formation. Additional methods, systems, and devices are also disclosed.

Abstract: This disclosure relates to a sensor for imaging boreholes with improved durability to impact along the wall of the borehole, which may protect the sensor from premature wear. Such an apparatus may include a housing, one or more button electrodes coupled to the housing, one or more current return electrodes couple to the housing, and a guard electrode disposed at least partly around the one or more button electrodes. The one or more button electrodes may transmit or receive an electrical or electromagnetic signal through the underground formation, and the one or more current return electrodes receive or transmit the signal. The guard electrode may block portions of the electrical or electromagnetic signal that did not pass through the underground formation. In addition, the guard electrode may include a number of holes to enable the guard electrode to couple to the housing while providing additional structural durability.

Abstract: This disclosure relates to a sensor for imaging boreholes with improved durability to impact along the wall of the borehole, which may protect the sensor from premature wear. Such an apparatus may include a housing, one or more button electrodes coupled to the housing, one or more current return electrodes couple to the housing, and a guard electrode disposed at least partly around the one or more button electrodes. The one or more button electrodes may transmit or receive an electrical or electromagnetic signal through the underground formation, and the one or more current return electrodes receive or transmit the signal. The guard electrode may block portions of the electrical or electromagnetic signal that did not pass through the underground formation. In addition, the guard electrode may include a number of holes to enable the guard electrode to couple to the housing while providing additional structural durability.

Abstract: A method for determining a depth related parameter of an instrument in a wellbore includes measuring movement of the instrument along the wellbore using a wheel sensor urged into contact with a wall of the wellbore. Movement of an instrument conveyance is measured proximate the surface. Measurements from the wheel sensor are calibrated using measurements of movement of the instrument conveyance. The depth related parameter of the instrument is determined using the calibrated wheel sensor measurements.

Abstract: Methods and systems for determining petrophysical parameters of a formation are provided. In one embodiment, a method includes acquiring formation data with a borehole imaging tool deployed in a well penetrating a formation and acquiring additional formation data with a dielectric logging tool deployed in the well. The method also includes calibrating the formation data acquired with the borehole imaging tool based on the additional formation data acquired with the dielectric logging tool. The calibrated formation data can then be used in determining a petrophysical parameter of the formation. Additional methods, systems, and devices are also disclosed.

Abstract: System and methods of generating calibrated downhole images of a subterranean formation (110) surrounding a wellbore (105). The method involves placing a pad at a distance from a highly conductive surface and measuring a current between return electrodes of the pad and the highly conductive surface. The current may be used to determine a theoretic impedance of the current path, and impedance amplitude and impedance phase may be calibrated using theoretical impedance phase and theoretical impedance amplitude. Multiple standoff calibrations and temperature variation calibrations may also be used.

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: In one embodiment, a computer-based method includes obtaining a first image where the first image includes one or more patterns, generating a second image that substantially removes or reduces the one or more patterns from the first image at least partially by automatically detecting the one or more patterns and a zone where the one or more patterns occur in the first image, converting the first image to frequency domain data, applying a multi-parameter filter to the frequency domain data to substantially remove or reduce the one or more patterns. The parameters may include bandwidths in a depth and azimuthal direction. The parameters may be adapted in the multi-parameter filter based on the one or more patterns. The method also includes transforming the frequency domain data to spatial domain data and outputting the second image based at least in part on the spatial domain data.

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 apparatus and method for making resistivity measurements of an underground formation surrounding a borehole is disclosed. The apparatus includes a conductive tool body section. The apparatus includes an electrically decoupling insulated tool body section mechanically coupled to the conductive tool body section. The apparatus includes a conductive current return (CR) tool body section mechanically coupled to the electrically decoupling insulated tool body section. The apparatus includes a pad mounted on the conductive tool body section that injects current into the formation at a frequency in a range above 100 kHz and below 10 MHz. The pad includes at least one button electrode that measures current injected into the formation. The pad also includes a standoff spacer affixed to the conductive plate configured for direct contact with the formation.

Abstract: Systems and methods are provided to obtain multiple resistivity measurements using a resistivity tool eccentered and rotating in a wellbore, which may be used to ascertain information relating to a drilling fluid in the wellbore. One such system includes a resistivity tool and data processing circuitry. The resistivity tool may become eccentered in a wellbore filled with drilling mud at least when the wellbore is at least partially deviated. The resistivity tool may also rotate within the wellbore and to obtain at least two resistivity measurements at different corresponding angles of rotation within the wellbore. The data processing circuitry may determine a mud phase angle by comparing the resistivity measurements obtained by the resistivity tool.

Abstract: Systems, tools and techniques for generating downhole parameters of a wellbore penetrating a subterranean formation and having a downhole fluid (108) therein are provided. A downhole tool with sensor pads (118a, 118b, 118c, 118d) is positioned in the wellbore (106) for emitting an electrical signal therefrom and for measuring the electrical signal. A downhole fluid unit is provided for generating downhole fluid measurements from the measured electrical signal passing through the downhole fluid and for generating a downhole fluid distribution profile (430) based on the downhole fluid measurements whereby separation of the downhole fluid may be indicated. A formation unit may be provided for generating formation measurements from the measured electrical signal passing through the subterranean formation.

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: System and methods of generating calibrated downhole images of a subterranean formation (110) surrounding a wellbore (105). The method involves placing a pad at a distance from a highly conductive surface and measuring a current between return electrodes of the pad and the highly conductive surface. The current may be used to determine a theoretic impedance of the current path, and impedance amplitude and impedance phase may be calibrated using theoretical impedance phase and theoretical impedance amplitude. Multiple standoff calibrations and temperature variation calibrations may also be used.

Abstract: Techniques related to making resistivity measurements of an underground formation surrounding a borehole involve using a tool having an insulating pad mounted on the conductive body of the tool. The pad has a current injector electrode and a current return electrode electrically isolated from each other and mounted on a face of the pad. The pad is positionable in use to be adjacent the wall of the borehole. At least two impedance ratios are determined. The first is the ratio of the electrical impedance between the current injector electrode and the tool body and the electrical impedance between the current return electrode and the tool body. The second is the ratio of the electrical impedance between the current injector electrode and the formation, and the electrical impedance between the current return electrode and the formation on the other hand.

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: Techniques related to making resistivity measurements of an underground formation surrounding a borehole involve using a tool having an insulating pad mounted on the conductive body of the tool. The pad has a current injector electrode and a current return electrode electrically isolated from each other and mounted on a face of the pad. The pad is positionable in use to be adjacent the wall of the borehole. At least two impedance ratios are determined. The first is the ratio of the electrical impedance between the current injector electrode and the tool body and the electrical impedance between the current return electrode and the tool body. The second is the ratio of the electrical impedance between the current injector electrode and the formation, and the electrical impedance between the current return electrode and the formation on the other hand.

Abstract: A system and method for determining a downhole parameter includes a downhole tool having a sensor. The sensor includes a pad having insulation, and return(s) positionable in the insulation. The return(s) are adapted to exchange a current with a power source, and a portion of the return(s) may be in a fluid zone. The sensor includes a mud button positionable within the fluid zone and in the insulation a distance from the return(s). The mud button are suitable for 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. The current exchanged with the mud button generates a measurement of the downhole fluid.

Abstract: Systems and methods are provided to obtain multiple resistivity measurements using a resistivity tool eccentered and rotating in a wellbore, which may be used to ascertain information relating to a drilling fluid in the wellbore. One such system includes a resistivity tool and data processing circuitry. The resistivity tool may become eccentered in a wellbore filled with drilling mud at least when the wellbore is at least partially deviated. The resistivity tool may also rotate within the wellbore and to obtain at least two resistivity measurements at different corresponding angles of rotation within the wellbore. The data processing circuitry may determine a mud phase angle by comparing the resistivity measurements obtained by the resistivity tool.

Abstract: Techniques related to making resistivity measurements of an underground formation surrounding a borehole involve using a tool having a pad mounted on the body of the tool. The pad has a current injector electrode and a current return electrode mounted on the pad face and arranged such that the current injector and return electrodes are electrically isolated from each other when in use. Two impedance ratios are determined. The first is a ratio of the electrical impedance between the current injector electrode and the tool body, and the electrical impedance between the current return electrode and the tool body. The second is a ratio of the electrical impedance between the current injector electrode and the formation, and the electrical impedance between the current return electrode and the formation. The tool is arranged such that the two impedance ratios differ by 25% or less of the larger impedance ratio.