A centralizing perforating gun for perforating a tubular in a wellbore include a gun housing, perforating charges positioned within the gun housing and detonatable to perforate the tubular, and a centralizing system. The centralizing system includes an extendable member configured to move between a retracted position and an extended position. The extendable member is configured to engage a surface of the tubular in the extended position, thereby biasing the centralizing perforating gun away from the surface of the tubular.

A downhole sensor position adjustment device on a downhole sensor assembly comprising a set of centralizers and a sensor array coupled to an adjustable framework radially positionable by an actuator. The actuator includes an extend-retract mechanism to radially position the sensor array a predetermined radial distance to an inner surface of a casing. A controller communicatively coupled to the extend-retract mechanism is configured to actuate the extend-retract mechanism. A positioning sensor provides feedback of the predetermined radial distance of the sensor array to the inner surface of the casing.

There are described devices and methods for use, for example, with signaling in a well, e.g. using a well structure of the well. Such signaling may include the communication of power and/or data signals. The devices and methods used may assist with efficient and/or effective communication of such signals. In some examples, there is described deployable devices and methods, e.g. a deployable device for signaling contact in a well, and methods associated therewith.

A device for centering a sensor assembly in a bore comprises a plurality of arm assemblies connected first and second support members. Each arm assembly comprises a first arm pivotally connected to the first support member, a second arm pivotally connected to the second support member, and a third arm pivotally connected between the first and second arms. The third arm is pivotally connected to a third support member positioned axially between the first and second support members. The third arm extends across the longitudinal axis of the device so that in use each arm assembly contacts opposite sides of the bore to centralise the sensor assembly in the bore.

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 technique facilitates control over the positioning of a well tool in a wellbore or other type of borehole. A well tool is combined with a centralizer system. The centralizer system has a plurality of extension members which are oriented to extend outwardly, e.g. radially outwardly, from the well tool. The extension members of the plurality of extension members are controllable to enable controlled positioning of the well tool within the borehole. The extension members may be actuated to centralize the well tool along a desired borehole axis.

A high expansion anti-rotation anchor catcher includes a helical track positioned on an exterior surface of a tubular body. An expandable gripper cage is provided having an axially fixed hub mounted for rotation about the tubular body and an axially movable hub mounted for rotation about the tubular body. Pivoting linkages which support outwardly oriented grippers extend between the axially fixed hub and the axially movable hub. The axially movable hub has a track follower that engages the helical track on the exterior surface of the tubular body. Rotation of the tubular body in a first rotational direction causes the track follower to move along the helical track toward the axially fixed hub, thereby placing the expandable gripper cage in compression and causing the pivoting linkages and grippers to pivot outwardly away from the tubular body to secure the anchor in position.

A scratch tester has at least one cutter that moves simultaneously both rotationally and axially relative to the rock it is cutting. When rotational and axial movements are constant, the cutter generates a helical groove in the rock. In borehole embodiments, the scratch tester is fixed at a desired location using centralizers, and the cutter is provided on a motorized platform/track that translates between the centralizers and rotates around a central axis. The cutter faces outward and extends via a cutter arm to engage and carve a helical groove in the borehole wall. A laboratory scratch tester includes a holder for a solid cylindrical core sample and a motorized translating frame on which a cutter extends. The cutter is directed toward the core sample, and the holder with the core sample is rotated by a motor so that as the cutter translates relative thereto, a helical groove is cut thereinto.

A device and method to compress and store ultrasound data from an ultrasound logging device. The logging device is deployed in a well or pipe to be logged with one or more ultrasound transducers, preferably an array of transducers. On-board the device, are processors and memory units for convolving the ultrasound data with a wavelet transformation to generate wavelet coefficients and then compress the wavelet coefficients to generate compressed wavelet coefficients. The compressed wavelet coefficients are stored on the memory units and transferred to a remote computer once the device leaves the well or pipe.

A downhole tool, for removing sections of metal tubing, said downhole tool comprising at least one conductive element being arranged to corrode a section of metal tubing using an electrolytic process, said conductive element being made of electric conductive material, an apparatus to establish a connection to the metal tubing, and a source of electrical power.