A well tool can be used in a wellbore that can measure characteristics of an object in the wellbore. The well tool includes an ultrasonic transducer for generating an ultrasonic wave in a medium of the wellbore. The ultrasonic transducer includes a front layer, a rear layer, backing material coupled to the rear layer, and piezoelectric material coupled to the front layer and to the backing material. The rear layer can improve signal-to-noise ratio of the transducer in applications such as imaging and caliper applications.

A measurement tool may be positioned downhole in a wellbore for measuring formation properties and drilling mud properties during a drilling operation. The measurement tool may include a body and an antenna. The body may include magnets for generating a magnetic field and a transmitter for transmitting a radiofrequency pulse. The antenna may be positioned proximate to the body to measure properties using nuclear magnetic resonant frequencies. The antenna may measure formation properties in a first volume of a formation using a first frequency. The antenna may measure drilling mud properties in a second volume in a borehole using a second frequency.

A measurement tool may be positioned downhole in a wellbore for measuring formation properties and drilling mud properties during a drilling operation. The measurement tool may include a body and an antenna. The body may include magnets for generating a magnetic field and a transmitter for transmitting a radiofrequency pulse. The antenna may be positioned proximate to the body to measure properties using nuclear magnetic resonant frequencies. The antenna may measure formation properties in a first volume of a formation using a first frequency. The antenna may measure drilling mud properties in a second volume in a borehole using a second frequency.

According to one embodiment, a wall detection device includes an acquirer and processing circuitry. The acquirer acquires a point cloud, which includes a series of coordinates of a plurality of points corresponding to a first wall and a second wall that oppose each other. The processing circuitry detects a first detected wall and a second detected wall based on a model and the acquired point cloud, the model representing a first plane which corresponds to the first detected wall and indicates a surface of the first wall and a second plane which corresponds to the second detected wall and indicates a surface of the second wall, and the model representing the first plane and the second plane being parallel to each other.

According to one embodiment, a wall detection device includes an acquirer and processing circuitry. The acquirer acquires a point cloud, which includes a series of coordinates of a plurality of points corresponding to a first wall and a second wall that oppose each other. The processing circuitry detects a first detected wall and a second detected wall based on a model and the acquired point cloud, the model representing a first plane which corresponds to the first detected wall and indicates a surface of the first wall and a second plane which corresponds to the second detected wall and indicates a surface of the second wall, and the model representing the first plane and the second plane being parallel to each other.

A measuring device for a tube is disclosed. The measuring device includes a drift tool configured to verify roundness of the tube, a first electromagnetic (EM) emitter disposed on the drift tool and configured to emit EM waves while the drift tool drifts inside the tube, and an EM receiver disposed on the drift tool and configured to receive the EM waves reflected from an internal surface of the tube, wherein parameters of the emitted and received EM waves are analyzed to compute an internal diameter of the tube.

A measuring device for a tube is disclosed. The measuring device includes a drift tool configured to verify roundness of the tube, a first electromagnetic (EM) emitter disposed on the drift tool and configured to emit EM waves while the drift tool drifts inside the tube, and an EM receiver disposed on the drift tool and configured to receive the EM waves reflected from an internal surface of the tube, wherein parameters of the emitted and received EM waves are analyzed to compute an internal diameter of the tube.

Waves from cement bond logging with a sonic logging-while-drilling tool (LWD-CBL) are often contaminated with tool waves and may yield biased CBL amplitudes. The disclosed LWD-CBL wave processing corrects the first echo amplitudes of LWD-CBL before calculating the BI. The LWD-CBL wave processing calculates a tool wave amplitude and a phase angle difference as the difference of the phases between the tool waves and casing waves. The tool waves are then used to correct the LWD-CBL casing wave amplitude and remove errors introduced from tool waves. In conjunction with the sets of operations described, the LWD-CBL wave processing also include array preprocessing operations. Array preprocessing may employ variation of bandpass filtering and frequency-wavenumber (F-K) filtering operations to suppress tool wave.

Methods and systems pertaining to a processing system and a downhole logging tool for investigating nested tubulars in a borehole. The downhole logging tool includes a transmitter coil for emitting a broadband excitation signal including one or more step excitations. The downhole logging tool also includes receiver coils including at least two receiver coils spaced apart from the transmitter coil at respective first and second distances from the transmitter, the first and second distances being distinct from each other, and each receiver coil being able to receive a response signal resulting from the excitation signal. The downhole logging tool also includes an acquisition system for recording the excitation signal and the response signal of each receiver coil over time. The processing system derives information indicative of variations in individual thicknesses of the nested casing tubulars based on variations of the response signals over time.

Methods and systems pertaining to a processing system and a downhole logging tool for investigating nested tubulars in a borehole. The downhole logging tool includes a transmitter coil for emitting a broadband excitation signal including one or more step excitations. The downhole logging tool also includes receiver coils including at least two receiver coils spaced apart from the transmitter coil at respective first and second distances from the transmitter, the first and second distances being distinct from each other, and each receiver coil being able to receive a response signal resulting from the excitation signal. The downhole logging tool also includes an acquisition system for recording the excitation signal and the response signal of each receiver coil over time. The processing system derives information indicative of variations in individual thicknesses of the nested casing tubulars based on variations of the response signals over time.