A method for investigating well integrity, the method including pumping a magnetic fluid into an annulus of the well; magnetizing with a magnet the magnetic fluid while in the annulus of the well; moving a magnetic sensing probe through a casing of the well and recording a magnetic field generated by the magnetic fluid; and processing the recorded magnetic field to determine a distribution of magnetic particles into the magnetic fluid in the annulus.

The disclosure provides an acoustic logging device comprising a first tubular member comprising a plurality of grooves disposed on an exterior of the first tubular member. The acoustic logging device further comprises a ring transmitter module disposed around an exterior of the first tubular member, which comprises a piezoelectric (PZT) ring transmitter, a transmitter sleeve, wherein the PZT ring transmitter is disposed within the transmitter sleeve, and a cage, wherein the transmitter sleeve is disposed between the cage and the exterior of the first tubular member, wherein the transmitter sleeve is disposed over the plurality of grooves. The acoustic logging device further comprises a plurality of dual bender transmitters, wherein there is a gap disposed the plurality of dual bender transmitters in the exterior of the first tubular member, wherein there is an array of holes connecting each of the gaps together and providing fluid communication between the gaps.

A wellbore tool includes a body having a longitudinal axis and an outer circumferential surface. The wellbore tool includes moveable arms, housings, actuators, a temperature sensor, a pressure sensor, and a heat source, such as a microwave source. Each moveable arm is coupled to a respective actuator and a respective housing. Each actuator is configured to move the respective moveable arm. The temperature sensor is configured to measure a temperature of the subterranean formation. The pressure sensor is configured to measure a pressure of the subterranean formation. The microwave source is configured to generate microwave radiation. Methods of analyzing acquired transient temperature and transient pressure data for formation evaluation are also described.

A wellbore tool includes a body having a longitudinal axis and an outer circumferential surface. The wellbore tool includes moveable arms, housings, actuators, a temperature sensor, a pressure sensor, and a heat source, such as a microwave source. Each moveable arm is coupled to a respective actuator and a respective housing. Each actuator is configured to move the respective moveable arm. The temperature sensor is configured to measure a temperature of the subterranean formation. The pressure sensor is configured to measure a pressure of the subterranean formation. The microwave source is configured to generate microwave radiation. Methods of analyzing acquired transient temperature and transient pressure data for formation evaluation are also described.

A downhole antenna tool is disclosed for downhole well-logging or other downhole operations. Antenna bars are provided for winding of coils through associated coil carriers of individual ones of the antenna bars. The antenna bars with the wound coils are coated with a protection layer and are releasably coupled to a substrate of the downhole antenna tool using, for example, a silicone cushion layer.

A composition sensor for measuring composition of fluid mixtures is presented. The composition sensor includes a plurality of high-brightness emission sources having respective spectrally narrow wavelength emission bands in the infrared region. The wavelength emission bands overlap absorption wavelength bands of the composition. The wavelength emission bands are wavelength multiplexed and time multiplexed prior to emission through a fluid mixture. A single optical detector senses the emitted light. The composition sensor includes arms that can rotate to measure composition at different angular position of a pipe in a lateral section of an oil well. Rotation of the arms is provided by rotation of an element of a mobile vessel to which the arm is rigidly coupled. The rotation of the arms is provided by a rotation of a nose of the mobile vessel that rotates independently from a main body of the mobile vessel.

A composition sensor for measuring composition of fluid mixtures is presented. The composition sensor includes a plurality of high-brightness emission sources having respective spectrally narrow wavelength emission bands in the infrared region. The wavelength emission bands overlap absorption wavelength bands of the composition. The wavelength emission bands are wavelength multiplexed and time multiplexed prior to emission through a fluid mixture. A single optical detector senses the emitted light. The composition sensor includes arms that can rotate to measure composition at different angular position of a pipe in a lateral section of an oil well. Rotation of the arms is provided by rotation of an element of a mobile vessel to which the arm is rigidly coupled. The rotation of the arms is provided by a rotation of a nose of the mobile vessel that rotates independently from a main body of the mobile vessel.

A method and a system for collecting data at a fixed point in a wellbore are provided. An exemplary method includes dropping an untethered measurement tool (UMT) in the wellbore, switching a first magnet to drop a ballast from the UMT at a ballast drop condition, switching a second magnet to attach the UMT to a wall of the wellbore at a wall attachment condition. Data is collected in the UMT while the UMT is attached to the wall of the wellbore. The second magnet is switched to release the UMT from the wall of the wellbore at a wall release condition. The UMT is collected from the wellbore and the data is downloaded from the UMT.

A system for regulating a pump down operation may include a controller, a motor drive, a parameter estimation unit and a controller design unit. In examples, the controller may be configured to identify a difference between a downhole tension set-point to an actual downhole tension. The motor drive may be configured to adjust a line speed set point of the motor drive based at least in part on the difference from the controller to create an actual line speed from the motor drive to follow the downhole tension set-point. The parameter estimation unit may be configured to produce a fluid drag coefficient, a friction coefficient, and a line speed delay constant. The controller design unit may be configured to send one or more control gains to the controller based at least in part on the fluid drag coefficient, the friction coefficient, and the line speed delay constant.

A tool for use in well tubing is provided. The tool substantially spans a diameter of well tubing. Alternatively or in addition the tool extends longitudinally in well tubing and has radially adjacent batteries. A method of using the tool in well tubing is further provided. The method comprises transferring a signal from the tool to another tool.