An eddy current (EC) detection system comprises an EC probe including a plurality of sensors to provide corresponding EC response signals; and processing circuitry to evaluate speed of the EC probe based on a measurement of similarity of the EC response signals; determine whether the speed of the EC probe is too fast or two slow based on quality of the measurement; and generate a command to adjust speed of the EC probe during further EC inspection.

A system and method for non-destructive analysis of a structure. A probe acquires a transient time based reference signal and at least one test signal. The reference signal and test signals are transformed to the frequency domain. The frequency domain test signal can be normalized using the frequency domain reference signal. Parameters of interest are evaluated at each test location by iteratively determining estimated parameter values, generating an estimated frequency domain test signal using the estimated parameter values and determining the convergence between the estimated frequency domain test signal and the normalized frequency domain test signal. The parameters values are determined as the estimated parameter values resulting in a maximized convergence between the estimated signal and the normalized test signal. The parameter values can be used to visualize and model various features of the structure.

An eddy current (EC) detection system comprises an EC probe including a plurality of sensors to provide corresponding EC response signals; and processing circuitry to evaluate speed of the EC probe based on a measurement of similarity of the EC response signals; determine whether the speed of the EC probe is too fast or two slow based on quality of the measurement; and generate a command to adjust speed of the EC probe during further EC the inspection.

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.

A method for measuring formation conductivity distribution based on transient electromagnetic eddy current field is provided. The method includes arranging a transmitter coil and a first array receiver coil to a target stratum of a transmitter well, arranging a second array receiver coil to a target stratum of a receiver well, periodically turning on and off the transmitter coil, moving the transmitter coil and the first array receiver coil for a first preset distance, acquiring a first eddy current signal of the first array receiver coil and a second eddy current signal of the second array receiver coil in a moving process of the first preset distance, moving the second array receiver coil for a second preset distance, moving the transmitter coil and the first array receiver coil for the first preset distance till the measurement of the whole well segments is completed, and obtaining formation conductivity distribution.

A system and method for non-destructive analysis of a structure. A probe acquires a transient time based reference signal and at least one test signal. The reference signal and test signals are transformed to the frequency domain. The frequency domain test signal can be normalized using the frequency domain reference signal. Parameters of interest are evaluated at each test location by iteratively determining estimated parameter values, generating an estimated frequency domain test signal using the estimated parameter values and determining the convergence between the estimated frequency domain test signal and the normalized frequency domain test signal. The parameters values are determined as the estimated parameter values resulting in a maximized convergence between the estimated signal and the normalized test signal. The parameter values can be used to visualize and model various features of the structure.

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.

Described are various approaches for estimating the total thickness of a set of pipes from the phase of the mutual impedance between transmitter and receiver measured with an eddy-current logging tool disposed interior to the pipes, in conjunction with a simulated functional relationship between the phase and the total thickness.