A logging while drilling tool for measuring a geological formation surrounding a wellbore includes a tool body having one or more sensor pads. Each sensor pad is coupled to the tool body by an extendable coupling that is operable to adjust the radial position of the sensor pad by extending away from or retracting toward the tool body. One or more sensors are mounted to each sensor pads and the sensors are operable to obtain a measurement a property of the formation. The tool also includes a downhole control unit having a transmitter and receiver. The downhole control unit is operable to receive the measurement and transmit the measurement to a surface controller, wherein the transmitted measurement indicates a measurement resolution.

This disclosure may relate to a system and method for calculating the mud angle from a downhole device. A method for estimating a mud angle may comprise: disposing a downhole tool into a borehole; extending an arm of the downhole tool to a first location, wherein a pad is disposed on the arm; taking a first impedance measurement with at least one button electrode, wherein the button electrode is disposed in a button array, wherein the button array is disposed on the pad; extending the arm to a second location; taking a second impedance measurement with the at least one button electrode; transmitting the first measurement and the second measurement to an information handling system; and estimating the mud angle from the first impedance measurement and the second impedance measurement with an information handling system.

This disclosure may relate to a system and method for calculating the mud angle from a downhole device. A method for estimating a mud angle may comprise: disposing a downhole tool into a borehole; extending an arm of the downhole tool to a first location, wherein a pad is disposed on the arm; taking a first impedance measurement with at least one button electrode, wherein the button electrode is disposed in a button array, wherein the button array is disposed on the pad; extending the arm to a second location; taking a second impedance measurement with the at least one button electrode; transmitting the first measurement and the second measurement to an information handling system; and estimating the mud angle from the first impedance measurement and the second impedance measurement with an information handling system.

A system for locating water floods, in some embodiments, comprises: multiple non-reference electrodes with insulative pads for coupling to a borehole casing; a reference electrode with an insulative pad for coupling to the borehole casing; and multiple transducers coupled to the reference and non-reference electrodes, each of said electrodes coupled to one or more of the multiple transducers, wherein each transducer coupled to a non-reference electrode determines a differential non-reference potential between that non-reference electrode and the reference electrode, and wherein a transducer that couples to the borehole casing determines an absolute reference potential between the borehole casing and the reference electrode; wherein the differential non-reference potentials are mathematically combined with the absolute reference potential to produce absolute non-reference potentials; wherein scaling weights are applied to said absolute non-reference potentials to produce scaled absolute potentials that are used to determine a water flood location.

Hydrocarbon wells and methods of interrogating fluid flow within hydrocarbon wells. The hydrocarbon wells include a wellbore and downhole tubing that defines a tubing conduit and extends within the wellbore. The hydrocarbon wells also include an interrogation device. The interrogation device is configured to indicate at least one property of fluid flow within the hydrocarbon wells. The hydrocarbon wells also include a downhole location at which the interrogation device is released into the tubing conduit and a detection structure configured to query the interrogation device to determine the at least one property of fluid flow within the hydrocarbon wells. The methods include releasing an interrogation device at a downhole location within a hydrocarbon well and flowing the interrogation device from the downhole location to a surface region. The methods also include querying the interrogation device to determine at least one property of fluid flow within the hydrocarbon well.

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. The apparatus includes extendable suspension means affixed to the conductive plate, that, when extended, cause direct contact between the standoff spacer and the formation.

Systems, devices, and methods for evaluating an earth formation. Methods include conveying a tool on a carrier in a borehole, the tool comprising a conducting tubular having a transmitter and receivers disposed thereon in a spaced-apart relationship; inducing a current in the earth formation using the transmitter; measuring with the first receiver a first time-dependent transient electromagnetic (TEM) signal induced by the formation responsive to the current; measuring with a second receiver a second time-dependent TEM signal induced by the formation responsive to the current; and using at least one processor to estimate a corrected time-dependent TEM signal using the first time-dependent TEM signal, the second time-dependent TEM signal, and a correction coefficient estimated as a function of a non-exponentiated ratio of distances r.sub.b and r.sub.m between the transmitter and the respective receivers.

Systems, devices, and methods for evaluating an earth formation. Methods include conveying a tool on a carrier in a borehole, the tool comprising a conducting tubular having a transmitter and receivers disposed thereon in a spaced-apart relationship; inducing a current in the earth formation using the transmitter; measuring with the first receiver a first time-dependent transient electromagnetic (TEM) signal induced by the formation responsive to the current; measuring with a second receiver a second time-dependent TEM signal induced by the formation responsive to the current; and using at least one processor to estimate a corrected time-dependent TEM signal using the first time-dependent TEM signal, the second time-dependent TEM signal, and a correction coefficient estimated as a function of a non-exponentiated ratio of distances r.sub.b and r.sub.m between the transmitter and the respective receivers.

A method of determining a concentration of hydrogen sulfide in a fluid comprises exposing a sensor to the fluid, the sensor comprising a pair of electrodes defining a gap therebetween and a sensing material bridging the gap between the electrodes, measuring a value of an electrical parameter of the sensor at an applied frequency of greater than about 10 kHz and a voltage of less than about 1.0 volt when the sensor is exposed to the fluid, and determining the concentration of hydrogen sulfide in the fluid based at least in part on the measured value of the electrical parameter. Related apparatuses and methods are also disclosed.

Apparatus, systems, and methods may operate to correct measured voltage data for selected weak differential measurements to provide corrected voltage data. Additional activity may include adjusting the corrected voltage data to remove level shifts in the measured voltage data caused by downhole tool impedance to provide adjusted voltage data, converting the adjusted voltage data into apparent resistivity data, inverting the apparent resistivity data to determine true resistivity values for a geological formation, and operating a controlled device according to the true resistivity values for the geological formation. Additional apparatus, systems, and methods are disclosed.