A method for identifying a collar using machine learning may include acquiring one or more measurements from one or more depth points within a wellbore including a tubular string, training a machine learning model using a training dataset to create a trained machine learning model, and identifying at least one hyperparameter using the trained machine learning model. The method may further include creating a synthetic model, wherein the synthetic model is defined by one or more pipe attributes, minimizing a mismatch between the one or more measurements and the synthetic model utilizing the at least one hyperparameter, updating the synthetic model to form an updated synthetic model, and repeating the minimizing the mismatch with the updated synthetic model until a threshold is met.

A method of fabricating a ferrite for use in a resistivity logging tool includes providing an uncured ferrite material, and pressing the uncured ferrite material into a channel to form the ferrite. The channel is defined on a surface of a bobbin associated with the resistivity logging tool, and the channel can be arcuate and extend at an angle offset from a central axis of the bobbin. The uncured ferrite material is then cured in place within the channels on the bobbin.

A method of fabricating a ferrite for use in a resistivity logging tool includes providing an uncured ferrite material, and pressing the uncured ferrite material into a channel to form the ferrite. The channel is defined on a surface of a bobbin associated with the resistivity logging tool, and the channel can be arcuate and extend at an angle offset from a central axis of the bobbin. The uncured ferrite material is then cured in place within the channels on the bobbin.

A system may include an electromagnetic (EM) logging tool for inspecting downhole tubulars. The EM logging tool may include a mandrel, at least one low-frequency transmitter coil disposed on the mandrel, at least one-low frequency receiver coil disposed on the mandrel, and at least one-high frequency sensor configured to measure one or more electromagnetic properties of a tubular.

Systems and methods of the present disclosure relate to calibration of a resistivity tool. A calibration method comprises deploying a transmitter in a known formation with a known resistivity property with a physical tilted angle θ relative to a longitudinal axis of the tool; deploying receivers in the known formation, wherein a physical tilted angle of a first receiver is θ relative to the longitudinal axis of the tool, and wherein a physical tilted angle of a second receiver is −θ, relative to the longitudinal axis of the tool; transmitting signals with the transmitter and measuring the signals at the receivers; combining measurements at two receivers with respect to a transmitter signal in the known formation; producing synthetic responses of the tool in the known formation using forward modeling; and calculating an effective tilted angle θ′ from real measurements and the synthetic responses.

A system and a method for evaluating a subterranean earth formation include a logging tool locatable in a wellbore dispose in the formation. The logging tool may include a transmitter antenna and a single receiver antenna. The transmitter antenna is configured to transmit a first electromagnetic signal into the subterranean earth formation. The system further includes a processor and a non-transitory memory device. The memory device includes instructions that cause the processor to control a current and a voltage sourced to the transmitter antenna, receive, via the single receiver antenna, a second electromagnetic signal emitted by the subterranean earth formation in response to receiving the first electromagnetic signal, and determine a resistivity of the subterranean earth formation based on the second electromagnetic signal.

A system and a method for evaluating a subterranean earth formation include a logging tool locatable in a wellbore dispose in the formation. The logging tool may include a transmitter antenna and a single receiver antenna. The transmitter antenna is configured to transmit a first electromagnetic signal into the subterranean earth formation. The system further includes a processor and a non-transitory memory device. The memory device includes instructions that cause the processor to control a current and a voltage sourced to the transmitter antenna, receive, via the single receiver antenna, a second electromagnetic signal emitted by the subterranean earth formation in response to receiving the first electromagnetic signal, and determine a resistivity of the subterranean earth formation based on the second electromagnetic signal.

A method and system for visualizing data to detect a collar. A method may comprise disposing an electromagnetic logging tool downhole; emitting an electromagnetic field from the transmitter; energizing a casing with the electromagnetic field to produce an eddy current; recording the eddy current from the casing with the receiver; creating a variable-density-log from the recorded eddy current; selecting a wrapping period for the variable-density-log; creating a wrapped-variable-density-log from the variable-density-log using the wrapping period; and determining at least one collar location and a pipe index with the wrapped-variable-density-log. A system for to detect a collar may comprise an electromagnetic logging tool. The electromagnetic logging tool may comprise a transmitter and a receiver, wherein the transmitter and the receiver may be a coil. The system may further comprise an information handling system.

A method and system for visualizing data to detect a collar. A method may comprise disposing an electromagnetic logging tool downhole; emitting an electromagnetic field from the transmitter; energizing a casing with the electromagnetic field to produce an eddy current; recording the eddy current from the casing with the receiver; creating a variable-density-log from the recorded eddy current; selecting a wrapping period for the variable-density-log; creating a wrapped-variable-density-log from the variable-density-log using the wrapping period; and determining at least one collar location and a pipe index with the wrapped-variable-density-log. A system for to detect a collar may comprise an electromagnetic logging tool. The electromagnetic logging tool may comprise a transmitter and a receiver, wherein the transmitter and the receiver may be a coil. The system may further comprise an information handling system.

A system may include an electromagnetic (EM) logging tool for inspecting downhole tubulars. The EM logging tool may include a mandrel, at least one low-frequency transmitter coil disposed on the mandrel, at least one-low frequency receiver coil disposed on the mandrel, and at least one-high frequency sensor configured to measure one or more electromagnetic properties of a tubular.