A chemical reaction heat source for use in heaters used in down-hole applications is provided. 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 temperatures 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 method for bonding a first downhole tool to a borehole tubular. The method may include applying solder particles, each particle having an outer shell and a core of liquid metal, to at least one of a surface of the first downhole tool or a surface of the borehole tubular. The method may also include rupturing the shells of the solder particles to release the liquid metal cores. The method may further include bonding the first downhole tool to the borehole tubular by allowing the released liquid metal core to solidify.

A centralizer assembly installed on a casing section. A bow spring assembly having bow spring members is installed around the outer surface of the casing section and can rotate about the outer surface of the casing section. At least one portion of the casing section is swaged to increase the outer diameter of that section. Bow spring heel supports prevent bow spring members from contacting the outer surface of the central casing section when compressed. Non-abrasive materials prevent damage to wellhead or other polished bore receptacles.

A method of cementing a casing in a wellbore extending from an Earth's surface into a subsurface includes providing a tube having a bi-frustoconical shape. The bi-frustoconical shape is defined by an upper tube part having an inverted frustoconical shape, a lower tube part having a frustoconical shape, and a waist intermediate between the upper tube part and the lower tube part. The tube is positioned in an annulus formed between the casing and a wall of the wellbore from a surface opening of the annulus. The tube is urged in a direction down the annulus and along the casing until the tube lands on a collar radially projecting from an outer surface of the casing into the annulus.

A centraliser (10) for use in centralising tubing (12) in a bore (W) comprises a first end collar (14), a second end collar (16) and a number of elongate strut members (18). The strut members (18) are interposed between the first end collar (14) and the second end collar (16) and are circumferentially arranged and spaced around the first end collar (14) and second end collar (16). The strut member (18) have a first end portion (20), a second end portion (22), an intermediate portion (24) and angled wing portions (26) which extend from the intermediate portion (24).

Systems and methods for cementing an annular space radially outward of a casing of a subterranean well include a float shoe located at a downhole end of the casing. A float valve is located within the float shoe and within a fluid flow path extending through the float shoe from an internal bore of the casing to an exterior surface of the float shoe. At least two wing members are located on an outer diameter surface of the casing, each of the wing members extending from the float shoe to an uphole end of the casing. The wing members are sized to define two or more separate sections of the annular space. A downhole splitter is located on a downhole surface of the float shoe. The downhole splitter is sized to seal between the downhole surface of the float shoe and an end surface of the subterranean well.

A plug for plugging wells, and in particular oil and gas wells, is provided. The plug has a plug body formed from an outer metal tube of a reduced thickness. The plug also has reinforcement means, attached to an inner surface of the outer tube, that give the plug a cross-sectional structural strength that is at least equivalent to that of a thicker metal tube. The plug has a central heater receiving void located along the axis of the plug to enable a plug deployment heater to be received therein. Also provided is a plug assembly with a variable cross-sectional area in a plane perpendicular to the plane in which the assembly is deployed during the plugging of underground conduits.

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.

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. The thrust device is coupled to a wheel arrangement to limit an outer diameter of the one or more thrust cups.

A centraliser includes a number of members extending between two collars for mounting the centraliser on a casing. The members are configured to contact a wall of the bore and centraliser the casing in the bore. The members are radially moveable between the casing and the bore wall. The members further include an intermediate portion and end portions, the end portions being relatively more flexible than the intermediate portion.