Abstract: A downhole drilling system is disclosed. The system may include a drill bit including first and second electrodes electrically coupled to a pulse-generating circuit to receive pulse drilling signals, a reference sensor in proximity to the drill bit, an additional sensor uphole from the reference sensor, and a sensor analysis system communicatively coupled to the reference sensor and to the additional sensor. The sensor analysis system may be configured to obtain measurements representing responses recorded simultaneously by the reference sensor and by the additional sensor during a pulsed drilling operation in a wellbore, generate modified measurements in which effects of variations in the pulse drilling signal on the measurements representing responses recorded by the additional sensor are reduced based on the measurements representing responses recorded by the reference sensor and determine, based on the modified measurements, a characteristic of a formation downhole from the drill bit.

Abstract: An apparatus, method, and system for multi-well ranging and planning of a second injector well in the presence of a first injector well in close proximity to a producer well. The method includes generating a three-well forward simulation model using survey data for a producer well, survey data for a first injector well, survey data for a first section of a second injector well, a producer well casing property profile, and a formation resistivity parameter. The method provides for determining the offset between the true magnetic sensor position in the BHA and a planned depth position. The method determines ranging distance and direction of the drilling well to target well using the offset between the true magnetic sensor position and the first planned depth position. The method helps to adjust directional drilling parameter to achieve constant ranging distance between drilling well and target well.

Abstract: Methods and systems are described that can be used for locating conductive bodies such as wellbore casing or piping disposed below the earth's surface. An electrical current can be excited in a conductive body in each wellbore in a given area to produce a magnetic field, and the magnetic field can be detected by a ranging tool. Location and current parameters can be determined for an estimated number of wellbores producing non-negligible contributions to the magnetic field, and the estimated number of wellbores can be adjusted until the number of contributing wellbores is determined. Location solutions can be returned for each of the contributing wellbores, and the location solutions can be employed to facilitate exploration of drilling applications such as well avoidance, well intersection and/or steam assisted gravity drainage (SAGD) steering operations.

Abstract: Methods and devices used to calibrate EM corrosion detection tools may estimate the effects of the presence of a core on measurements to enable more accurate corrosion detection in the well line. The methods may involve sending voltages to a core of a well tool disposed in the well line to obtain signals while the core is in a saturated and unsaturated state. Subsequent measurements using the core may be calibrated using a constant resulting from the division of the signals achieved at the core in the saturated and unsaturated states.

Abstract: A measurement is made of a formation containing a flood front with a downhole electromagnetic sensor. A parameter of a cross-bedding model is calculated by fitting the measurement to the cross-bedding model. A rock petrophysical parameter is calculated using the cross-bedding model. The cross-bedding model is updated using the rock petrophysical parameter. The updated cross-bedding model is used to make an operational decision.

Abstract: Methods, systems, and computer program products use current leakage rates to evaluate the resistivity of a subterranean formation around a drilling well in conjunction with a ranging operation. The evaluation entails obtaining a current distribution along a section of the drilling well as part of a ranging measurement. The current distribution allows the current leakage rate to be determined along that section of the drilling well. Multiple current leakage rates may then be determined along the drilling well to produce a leakage rate curve that may be matched with modeled or known leakage rate curves to estimate the formation resistivity around the drilling well. Formation resistivity may also be calculated from the current distribution using an appropriate equation. The ability to obtain a current distribution along a section of the drilling well as part of a ranging measurement allows formation resistivity to be evaluated in conjunction with ranging operations.

Abstract: The disclosed embodiments include systems and methods to image a borehole. In one embodiment, a borehole imaging system having a borehole imaging tool and a processor is provided. The borehole imaging tool includes a magnetic field source and an array of electrode buttons. The borehole imaging tool also includes a galvanic source operable to inject an electrical current through one or more electrode buttons of the array of electrode buttons into the formation. The processor is operable to determine a differential voltage between at least two electrode buttons of the array of the electrode buttons, and determine the current through the one or more electrode buttons. The processor is also operable to determine a magnetic susceptibility and a resistivity of the formation based on the differential voltage and the current, respectively, and construct a visual representation of the formation based on the resistivity and the magnetic susceptibility of the formation.

Abstract: The disclosed embodiments include downhole electromagnetic reservoir monitors, and systems and methods to monitor downhole reservoirs. In one embodiment, the electromagnetic reservoir monitor includes a galvanic transmitter deployed proximate a wellbore casing and having a source electrode and a return electrode, where a current flowing from the source electrode, through a formation, to the return electrode is altered by a fluid reservoir of the formation, and where an altered component of the current induces a secondary magnetic field. The electromagnetic reservoir monitor also includes a magnetic receiver having a tilted coil deployed proximate the wellbore casing, the tilted coil having an orientation relative to a cross sectional plane normal to a longitudinal axis of the wellbore casing, and the tilted coil operable to detect a component of the secondary magnetic field, where the secondary magnetic field is indicative of at least one property of the fluid reservoir.

Abstract: An inspection tool apparatus includes a core having an axial length. The axial length is determined based on a desired depth of inspection radially from the core. A plurality of arms are coupled to and extend radially from the core. The core and the plurality of arms comprise a high permeability magnetic material. The core or at least one of the plurality of arms is wound by a respective coil that is positioned to receive magnetic flux that is passing through the core or at least one of the plurality of arms.

Abstract: Apparatus and methods to investigate a multiple nested conductive pipe structure can be implemented in a variety of applications. An electromagnetic pulsed tool disposed in the multiple nested conductive pipe structure in a wellbore can make a set of log measurements and provide a measured log at different depths in the multiple nested conductive pipe structure. A test setup or library can provide a set of small defect log measurements. Processing circuitry can process the set of log measurements to generate thickness estimations of the multiple nested conductive pipes and processing circuitry can process the set of small defect log measurements to generate small defect thickness estimations. Processing circuitry can solve a system of equations involving the thickness estimations and the small defect thickness estimations to generate thickness variations for the multiple nested conducted pipes over the different depths. Additional apparatus, systems, and methods are disclosed.

Abstract: A method and system for electromagnetic ranging of a target wellbore. A method may comprise disposing an electromagnetic ranging tool in a wellbore, energizing a conductive member disposed in the target wellbore to create an electromagnetic field, measuring at least one component of the electromagnetic field from the target wellbore, performing at least two non-axial magnetic field measurements, performing at least one axial magnetic field measurement, calculating a processed non-axial magnetic field measurement using the at least two non-axial magnetic field measurements, calculating an end-of-pipe ratio with the processed non-axial magnetic field measurement and the at least one axial magnetic field measurement, and altering a course of the electromagnetic ranging tool based at least in part from the end-of-pipe ratio. A well ranging system may comprise a downhole assembly, a sensor comprising a first component and a second component, a drill string, and an information handling system.

Abstract: Systems and methods for active ranging-while-drilling (ARWD) for collision avoidance and/or well interception. A method for electromagnetic ranging of a target wellbore may include disposing an electromagnetic ranging tool in a wellbore, wherein the electromagnetic ranging tool comprises an electromagnetic transmitter and an electromagnetic receiver; exciting a subterranean formation with the electromagnetic transmitter; adjusting at least one orientation of the electromagnetic transmitter, the electromagnetic receiver, or both the electromagnetic transmitter and the electromagnetic receiver; exciting the target wellbore with the electromagnetic transmitter; measuring at least one component of an electromagnetic signal from the target wellbore with the electromagnetic receiver; and determining at least one ranging parameter of the target wellbore based, at least in part, on the at least one component of the electromagnetic field measured by the electromagnetic receiver.

Abstract: A method for taking measurements in a wellbore including lowering a downhole logging tool in the wellbore; obtaining, via the logging tool, a plurality measurements of a downhole element; processing the plurality of measurements to obtain a plurality of processed measurements; calculating a contour model based on the plurality of processed measurements; and determining a parameter of the downhole element based on the contour model.

Abstract: A downhole tool, comprising: a tool mandrel; a pad comprising a transmitter operable to transmit an electric current into a formation and a receiver operable to receive at least a portion of the electric current from transmitter; an extension from the tool mandrel that couples pad to tool mandrel; and a signal filter positioned in the downhole tool to suppress passage of mandrel leakage current that passes through tool mandrel to pad. A method of resistivity imaging, comprising: disposing a downhole tool into borehole; transmitting a current into formation surrounding the borehole with a transmitter that is extended from tool mandrel of the downhole tool towards borehole wall; and recording at least a portion of the current that returns to receiver of downhole tool, wherein a signal filter suppress passages of mandrel leakage current that passes through the tool mandrel to a pad on which the transmitter is disposed.

Abstract: Methods and devices used to calibrate EM corrosion detection tools may estimate the effects of the presence of a core on measurements to enable more accurate corrosion detection in the well line. The methods may involve sending voltages to a core of a well tool disposed in the well line to obtain signals while the core is in a saturated and unsaturated state. Subsequent measurements using the core may be calibrated using a constant resulting from the division of the signals achieved at the core in the saturated and unsaturated states.

Abstract: A look-ahead logging method includes obtaining an initial resistivity log. The method further includes deriving an initial formation model based on the initial resistivity log. The method further includes estimating deep resistivity measurements from the initial formation model and deriving a reduced-complexity formation model from the estimated deep resistivity measurements. The method further includes collecting actual resistivity measurements and inverting the actual resistivity measurements, using the reduced-complexity formation model, to obtain look-ahead or look-around parameter values. The method further includes displaying the look-ahead or look-around parameter values or storing the look-ahead or look-around parameter values on a non-transient information storage medium.

Abstract: A substance saturation sensing method includes making a resistivity measurement of a formation proximate to a well with a logging tool prior to installation of a casing string in the well. After the casing string is installed in the well, a first set of measurements of the formation is made with a monitoring system to generate a measured response. A set of calibration values is calculated based on the first set of measurements to produce a resistivity that matches the resistivity measurement. A second set of measurements of the formation is made with the monitoring system during or after saturating of a substance occurs in the formation. At least one parameter indicative of the saturating of the substance in the formation is determined based on the second set of the measurements and the set of calibration values.

Abstract: 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.

Abstract: A method of detecting a flood front through a subterranean formation, comprising, measuring a distance to the flood front, processing the measured distance using a predictor-corrector filter to determine a corrected distance to the flood front, and adjusting a formation device based on the corrected distance to control a flow of the flood front.

Abstract: A method of filtering measured responses of downhole pipes, obtained by electromagnetic (EM) logging tools, to correct for natural variations in downhole pipes during downhole pipe defect characterization. A further method of directly characterizing downhole pipe defects by obtaining measured responses at known pipe features, such as casing collars. An apparatus and system for characterizing downhole pipe corrosion is also disclosed.