A centralizer for use in high speed rotor dynamics applications includes a housing having a first end portion and a second end portion. The centralizer further includes a rotatable shaft positioned within a cavity of the housing. The centralizer also includes flexure springs that are each attached to and extend between the first end portion and the second end portion. The flexure springs are compressible toward a middle portion of the housing that is between the first end portion and the second end portion. The centralizer further includes roller wheels attached to the flexure springs.

An artificial lift system utilizing a downhole impeller-style pump and a motor at the surface. The system includes a centralizer for use with the rod string or tubing. The centralizer centralizes a rotating rod at intermediate points within the tubing string. The centralizer includes a plurality of flexure springs and bearings. A rod string tensioner induces a tension load on the rod string.

Embodiments described herein provide a multi-diameter thrust device that includes one or more thrust cups. Each thrust cup of the one or more thrust cups includes a first axial end hub disposed at a first axial end of the thrust cup; a second axial end hub disposed at a second axial end of the thrust cup; and a plurality of bowsprings. Each bowspring of the plurality of bowsprings includes a first axial end portion coupled to the first axial end hub and a second axial end portion coupled to the second axial end hub. The plurality of bowsprings are disposed circumferentially about a central axis of the multi-diameter thrust device.

Systems and methods include a computer-implemented method for predicting fluid holdups along the borehole or the pipe on surface and to perform fluid typing and fluid properties characterization. Acoustic waves are transmitted by an array of acoustic wave transducers. Each transducer is configured to transmit acoustic waves at a different frequency. The acoustic waves are received by an array of acoustic wave receivers fixed on the bow centralizer on the tool used in the borehole. Each receiver is configured to receive only the given frequency of a given transducer, forming a receiver-transducer pair for the given frequency. Acoustic speeds measured at each given frequency and analyzed. A model is generated based on the analyzing. The model is configured to predict fluid holdups across the borehole and to perform fluid typing and fluid properties characterization in one phase, two phase, and three phase applications of gas, oil, and water.

A centralizer for a downhole probe disposed within a pipe, the centralizer having an elongated, primary tubular member with two or more elongated centralizer strip assemblies extending along the primary tubular member. Each strip assembly has inner and outer hollow portions on the wall of the primary tubular member and spaced apart from one another about the circumference of the wall. The outer portion of each strip assembly comprises a flexible outer spring, and the inner portion of the strip assembly comprises a flexible inner spring. The inner portions of the strip assemblies engage the outer diameter of a probe and the outer portions of the strip assemblies engage the inner diameter of a pipe.

A centralizer for use in a wellbore includes: a body for disposing around a periphery of a casing or liner string, the body having a plurality of bow springs biased toward an expanded position; a mandrel for disposing around the periphery of the casing or liner string; a piston disposed around the mandrel and movable between a locked position and a release position; a plurality of dogs, each dog mounted to or formed integrally with the respective bow spring and captured by the piston in the locked position, thereby keeping the bow springs in a retracted position; an atmospheric chamber formed between the piston and the mandrel; and a fastener for releasably connecting the piston to the mandrel in the locked position.

A centralizer sub for cementing a tubular string in a wellbore includes: a tubular body; a centralizer disposed along an outer surface of the body and having a pair of collars and a plurality of bow springs connecting the collars; and a joint longitudinally coupling the centralizer to the body. The joint has a groove formed in and around the body outer surface, and a plurality of protrusions formed integrally with or mounted to one of the collars and configured to mate with the groove.

A wellbore radial positioning apparatus includes a tool body and a motor that actuates a traction wheel. The tool body is configured to be positioned within a wellbore. The motor driving the traction wheel is connected to the tool body and is configured to rotate the tool body in the wellbore. The traction tool is configured to frictionally contact or attach to the wellbore. The tool body is rotated in the wellbore by the action of the motor actuating the traction wheel.

A method involves determining an expansion charge able to selectively expand, without perforating or cutting through, a wall of a tubular in a wellbore. The method includes determining conditions in the wellbore, including hydrostatic pressure bearing on the tubular in the wellbore, and a physical characteristic of the tubular. At a second location other than the wellbore, at least one of the conditions determined in the wellbore is reproduced, and a test tubular is provided at the second location. A test expansion charge able to expand, without perforating or cutting through, the wall of the test tubular, is determined based on the determined conditions. The determined test expansion charge is positioned within the test tubular, and is then actuated to expand the wall of the test tubular radially outward, without perforating or cutting through the wall, to form a test protrusion in the wall of the test tubular.

A stop collar for mounting to a downhole tubular includes: a cylindrical housing having a threaded inner surface and a tapered inner surface; a compressible slip ring having teeth formed in an inner surface thereof and a pair of tapered outer surfaces; a solid cam ring having a tapered inner surface; and a cylindrical bolt having a threaded outer surface. A natural outer diameter of each ring is greater than a minor diameter of the threaded surfaces. Screwing the threaded surfaces of the housing and the bolt is operable to drive the tapered surfaces together, thereby compressing the slip ring such that the teeth engage a periphery of the tubular.