A chemical reaction heat source for use in heaters used in down-hole application. The heat source has a fuel composition that comprises thermite and a damping agent. The use of the thermite mix enables the heaters of the present invention to generate hotter temperature down wells. This in turn allows the use of Bismuth/Germanium alloys, which have higher melting points, to enable the production of plugs for the abandonment of deeper wells where subterranean temperatures are higher.

A centralizer device for center positioning of a bore hole component (90, 91) in a bore hole and a method for deploying such a centralizer are described. The centralizer device (100) is prepared to have two possible different states, one state being a locked state for improved deployment and another state being a released state for centring. The transition from the locked state to the released state is performed by introducing a pill of bore fluid having a pH-value outside range of pH-values of bore fluid in a well. The pill of bore fluid dissolves pH-soluble material in the centralizer device.

A centralizer for centralizing a pipe downhole in a well is provided. The centralizer includes a plurality of arcuate cuffs having first and second ends. The cuffs are affixed adjacent to the pipe's exterior wall, and positioned circumferentially adjacent around the pipe. The cuffs are flexible so as to be positioned in a first condition wherein the cuffs are retracted radially inward so as to be substantially flat against the pipe's exterior wall. The centralizer includes a lock for maintaining the cuffs substantially flat against the pipe's exterior wall until the centralizer has been transported downhole. Further, the centralizer includes an actuator for unlocking the lock so as to allow the cuffs to expand radially outward to form a loop wherein the loop has a central axis parallel to pipe's longitudinal axis. Preferably, the centralizer includes a collar causing the cuffs to all expand or retract together.

A centralizer assembly includes a centralizer configured to centralize a tubular in a wellbore. The centralizer includes a first end collar, a second end collar, and ribs extending between the first and second end collars. The assembly also includes a first stop collar disposed adjacent the first end collar and including an anchor. The anchor defines a generally rectangular anchor window extending therethrough. The anchor is configured to bear on an anchoring material secured to the tubular and received through the anchor window. The anchor material includes a thermal spray applied to the tubular. The first end collar is prevented from rotation with respect to the first stop collar.

A method of fabricating a centralizer for a tubular body in a wellbore is provided herein. The method includes providing a centralizer, wherein the centralizer include an elongated body having an inner surface and an outer surface, and wherein the inner surface defines a bore there through. The bore is dimensioned to slidingly receive a tubular body. The method also includes applying a first low-coefficient of friction treatment to the inner surface and the outer surface using a ferritic nitro-carburizing process. The method further includes depositing a second low-coefficient of friction treatment onto at least the inner surface. The coatings are designed to provide a reduced coefficient of friction on the surfaces.

A stop collar for a tubular and method for installing a stop collar on a tubular. The stop collar includes a flexible member extending circumferentially around the tubular more than once. A tension force on the flexible member causes the flexible member to apply a radially-inward gripping force on the tubular. The stop collar may also include a shield disposed around at least a portion of the flexible member, to protect the flexible member in a downhole environment. The stop collar may also or instead include an adhesive disposed radially between the flexible member and the tubular.

A centraliser comprises longitudinally spaced collars connected by a plurality of springs, each of the springs comprising two or more bow sections.

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.

A centralizer operable to connect with and centralize a downhole tool within a tubular string within a wellbore and to facilitate reception of electromagnetic signals transmitted through the Earth. The centralizer has a body, a first contacting member electrically connected to the body and extending radially away from the body such that the first contacting member contacts an inner surface of the tubular string to electrically connect the tubular string to the body, and a second contacting member electrically insulated from the body and extending radially away from the body such that the second contacting member contacts the inner surface of the tubular string to centralize at least a portion of the body within the tubular string.

A method and downhole tool assembly, of which the method includes measuring a thickness and a location of an outer diameter surface of the tubular at a plurality of transverse planes of the tubular, simulating a cutting process to determine a position for the outer diameter surface of the tubular in a lathe, such that, after the cutting process that was simulated is conducted, the thickness of the tubular is greater than a minimum thickness and an outer diameter defined by the outer diameter surface of the tubular is less than or equal to a maximum diameter, positioning the tubular in the lathe based on the simulation of the cutting process, cutting the outer diameter surface of the tubular to reduce the outer diameter thereof to at most the maximum diameter and thereby form a turned-down region, and positioning the downhole tool on the tubular in the turned-down region.