Abstract: Systems and methods for detection of downhole tubulars.

Abstract: Apparatus and techniques are described, such as for obtaining information indicative of a formation resistivity, such as using an array laterolog apparatus. For example, an electrical excitation is coupled from a well tool in a borehole to a geologic formation through which the borehole extends, the excitation coupled through excitation electrodes on the well tool selected according to a specified excitation mode, and induced voltages are received from the geologic formation resulting from the excitation using monitor electrodes selected according to the specified excitation mode. In some examples, a voltage difference between a first pair of monitor electrodes is estimated through use of the induced voltage received through at least one additional monitor electrode.

Abstract: The structural integrity and reliability of a downhole tool or mandrel may be improved by implementation of a design and configuration that does not require several separate components to be coupled together. An insulating sleeve is wrapped around the outside of a mandrel. Electrodes, both transmit and return, are wrapped around the insulating sleeve. The outside diameter of the mandrel is increased but the structural integrity and reliability of the mandrel is maintained as no gap sub is used to electrically isolate the electrodes from the mandrel. The insulating sleeve may be tapered at the edges to prevent excessive wear on the sleeve. The insulating sleeve may also extend the full distance between the electrodes to provide even more insulation.

Abstract: Systems and methods for utilizing diverse excitation sources in single well electromagnetic ranging. A method may include disposing an electromagnetic ranging tool in a wellbore, wherein the electromagnetic ranging tool may comprise one or more receivers, a coil source and an electrode source; performing a measurement with the one or more receivers of at least one component of a coil-induced magnetic field from the target wellbore to provide a coil measurement, wherein the coil-induced magnetic field may be induced by the coil source; performing a measurement with the one or more receivers of at least component of an electrode-induced electromagnetic field to provide an electrode measurement, wherein the electrode-induced electromagnetic field may be induced by the electrode source; and calculating at least one ranging parameter using, at least in part, the coil measurement and the electrode measurement.

Abstract: Apparatus, systems, and methods may operate to correct measured resistivity data for borehole effects to provide borehole-corrected apparent resistivity data for a non-invaded formation. Additional activity may include inverting the measured resistivity data or the borehole-corrected apparent resistivity data to provide non-invaded true resistivity values for the non-invaded formation, inverting the measured resistivity data to provide invaded true resistivity values for an invaded formation, determining true resistivity values for a geological formation associated with the measured resistivity data as a weighted combination of the non-invaded true resistivity values and the invaded true resistivity values, and operating a controlled device according to the true resistivity values for the geological formation.

Abstract: The structural integrity and reliability of a downhole tool or mandrel may be improved by implementation of a design and configuration that does not require several separate components to be coupled together. A button recessed within an insulation layer may be installed within a groove or recess of the downhole tool. The isolation layer electrically isolates the button from the downhole tool. The button and the isolation layer are installed such that the top surface of either does not extend beyond the outer surface of the downhole tool. Recessing the button and isolation layer in this manner prevents undue wear on the downhole tool as well as the button and isolation layer. The buttons may be arranged so that when excited the buttons may detect the presence of a target objects located at various distances, directions, and orientations from the downhole tool.

Abstract: Disclosed embodiments include various borehole imaging tools and methods to provide sensing surface configurations for improving the assessment of anisotropy in layered formations. In at least some embodiments, the borehole imaging tools employ a unitary conductive body to provide a wall-contacting face with grooves that define multiple elongated sensing surfaces. This wall-contacting face can be provided on an extendable sensor pad of a wireline logging tool or embedded on the outer surface of a LWD stabilizer fin. Toroids may be seated in the grooves around each elongated sensing surface for measuring the current flow through each sensing surface. The elongated sensing surfaces can be arranged in pairs as a series of rectangular-shaped grooves that are aligned perpendicularly to each other within each of the pairs to improve detection of anisotropy in thin layered formations and improve the sensitivity to dipping in anisotropic formations.

Abstract: Calibration tools and procedures that provide one or more calibration methods for multi-component induction tools can include use of a tilted elliptical loop and a circular loop. Measurement signals may be used for analytic calibration of a multicomponent induction tool. Additional apparatus, systems, and methods are disclosed.

Abstract: A method and system for identifying a target well. A system for identifying a target well may comprise placing an electromagnetic ranging tool in a wellbore, transmitting an electromagnetic field into a formation, inducing an eddy current within a target well, measuring a second electromagnetic field from the target well, calculating a position or an orientation of a transmitter or a receiver relative to another position, and calculating at least one parameter of the target well. An electromagnetic ranging system may comprise an electromagnetic ranging tool and an information handling system. The information handling system may be operable to calculate a position and/or an orientation of a transmitter or a receiver relative to another position on the electromagnetic ranging tool disposed on a borehole assembly, and calculate at least one parameter of a target well from the calculated position or orientation of the transmitter and the receiver.

Abstract: A method and electromagnetic ranging system for determining the location of a target well. A method may comprise taking a first measurement with an electromagnetic ranging tool at a first position and calculating a first modeled signal. Additionally, calculating a calibration for the electromagnetic ranging tool from at least the first measurement and the first modeled signal, taking a second measurement with the electromagnetic ranging tool at a second position, and calculating a calibrated measurement. The method may comprise determining a distance, direction, and/or orientation to a target wellbore using at least the calibrated measurement. An electromagnetic ranging system may comprise an electromagnetic ranging tool and an information handling system coupled to the electromagnetic ranging tool.

Abstract: Systems and methods for detection of pipe characteristics, such as defect detection of downhole tubulars and overall thickness estimation of downhole tubulars (e.g., pipes such as casing and/or production tubing).

Abstract: Apparatus and methods are described, such as for obtaining formation parameters of a geological formation. The method includes measuring a resistivity image of the geological formation. The measured resistivity image is compared to a modelled resistivity image where the modelled resistivity image is represented by estimated formation parameters. A cost function is calculated from the measure resistivity image and the modelled resistivity image. The estimated formation parameters are adjusted to generate a set of final formation parameters that represents a modelled resistivity image having a smallest cost function.

Abstract: Various embodiments include apparatus and methods related to finding a position in an underground formation. Apparatus and methods can include receiving signals from a receiver in an underground formation in response to signals generated from transmitting sources, each of the transmitting sources located at a known position; and processing the received signals, based on the signals generated from the transmitting sources, to determine the position of the receiver. A number of techniques can be applied to processing the received signal. Additional apparatus, systems, and methods are disclosed.

Abstract: A ranging system utilizes gradiometric data to determine the distance between a first and second well without any knowledge or involvement of the borehole or formation characteristics. In general, this is achieved by deploying a downhole assembly comprising transmitters and receivers having magnetic dipoles, along with bucking receivers positioned between the transmitters and receivers, wherein the gradient field is measured in a radial direction along the downhole assembly.

Abstract: Systems and methods for detection of pipe characteristics, such as defect detection of downhole tubulars and overall thickness estimation of downhole tubulars (e.g., pipes such as casing and/or production tubing).

Abstract: Systems and methods for detection of downhole tubulars.

Abstract: An example method for downhole operations using a magnetic monopole includes positioning at least one of a transmitter and a receiver within a first borehole. At least one of the transmitter and the receiver may be a magnetic monopole. The transmitter may generate a first magnetic field, and the receiver may measure a signal corresponding to the first magnetic field. A control unit communicably coupled to the receiver may determine at least one characteristic using the received signal.

Abstract: Various embodiments include apparatus and methods related to finding a position in an underground formation. Apparatus and methods can include receiving signals from a receiver in an underground formation in response to signals generated from transmitting sources, each of the transmitting sources located at a known position; and processing the received signals, based on the signals generated from the transmitting sources, to determine the position of the receiver. A number of techniques can be applied to processing the received signal. Additional apparatus, systems, and methods are disclosed.

Abstract: Various embodiments include apparatus and methods related to finding a position in an underground formation. Apparatus and methods can include receiving signals from a receiver in an underground formation in response to signals generated from transmitting sources, each of the transmitting sources located at a known position; and processing the received signals, based on the signals generated from the transmitting sources, to determine the position of the receiver. A number of techniques can be applied to processing the received signal. Additional apparatus, systems, and methods are disclosed.

Abstract: Systems and methods for utilizing diverse excitation sources in single well electromagnetic ranging. A method may include disposing an electromagnetic ranging tool in a wellbore, wherein the electromagnetic ranging tool may comprise one or more receivers, a coil source and an electrode source; performing a measurement with the one or more receivers of at least one component of a coil-induced magnetic field from the target wellbore to provide a coil measurement, wherein the coil-induced magnetic field may be induced by the coil source; performing a measurement with the one or more receivers of at least component of an electrode-induced electromagnetic field to provide an electrode measurement, wherein the electrode-induced electromagnetic field may be induced by the electrode source; and calculating at least one ranging parameter using, at least in part, the coil measurement and the electrode measurement.