Abstract: A gas-actuated dump bailer tool that can be opened/closed under the direct or indirect action of gas generated by a gas-generating chemical reaction mixture housed within the dump bailer. Additionally, a downhole tool assembly that employs the dump bailer together associated methods of using the dump bailer downhole in an oil/gas well.

Abstract: A plug with composite reinforced end(s) and a mostly-bismuth-alloy middle section. At least one end comprises a composite material. One end is a composite, with a bismuth alloy and a particulate material of greater strength than the bismuth material. A plug having both ends of the composite material.

Abstract: A chemical reaction heat source for use in heaters for downhole applications is provided. The heat source has a solid fuel composition that comprises thermite and a binding agent. The binding agent serving to maintain the solid form of the solid fuel composition during burning and ensure a predetermined uniform heating pattern can be provided for longer. The solid fuel composition can be provided in the form of blocks. The solid fuel composition can also be provided in the form of a plurality of fragments that, during burning, behave more like powdered thermite and have the ability to flow.

Abstract: A downhole tool for use in a gas or oil well is provided. The tool comprising a length of tubing having at least one annular sealing means mounted on the outer surface thereof. The annular sealing means, which are formed from a eutectic/bismuth based alloy, serve to secure the downhole tool in position within an oil or gas well during so that the tool can carry out its function.

Abstract: The method comprising providing a eutectic alloy based downhole tool comprising a tubular body with eutectic alloy located on an outer surface thereof, said tool having an outer diameter with a clearance from the inner diameter of the well. The downhole tool is delivered to a target region within an oil/gas well where the tool is to be deployed. Once the tool is in position within the well a tubular expanding tool is run through the interior of the tubular body so as to increase the outer diameter of the sealing downhole tool and in so doing reduce the clearance between the alloy and the well. A heater is deployed within the tubular body proximal to the alloy and operated to melt the alloy. The alloy is then allowed to cool and resolidify, whereby the tool is sealed in place within the target region of the well using the alloy.

Abstract: The present disclosure provides a chemical heater for use in down-hole operations together with methods for operating such in oil/gas wells. The chemical heater comprises a heater body housing a chemical reaction heat source material. The heater body has a leading end that, in use, is deployed down-hole first. The heater is provided with ignition means, located in a heating zone proximal to the leading end of the heater body, for triggering a chemical reaction in the chemical reaction het source material located in the heating zone. The heater is further provided with an actuator housed within the heater body and configured to urge the chemical reaction heat source material towards the heating zone so as to generate a focused heating pattern.

Abstract: The present invention provides a cartridge (1) for a chemical heater used in down-hole operations. The cartridge (1) comprises a quantity of a chemical reaction heat source (2) wrapped in a temporary coating (3) that is capable of maintaining the shape of the cartridge (1) prior to use but which is consumed during the burn of the heater. The present invention also provides a eutectic/bismuth based alloy well plugging/sealing tool (5). The tool (5) having a tubular heater body (6) with an internal cavity (8) capable of receiving a chemical heat source and a quantity of eutectic/bismuth based alloy (7) provided in thermal communication with the heater body (6) around an outer surface of the heater body (6). The tool has a sleeve (10) provided around an outer surface of the alloy (7), which insulates and/or mechanically protects the alloy (7) down-hole. In this way the sleeve (10) enables the diameter of tool (5) to be reduced whilst maintaining its functionality.

Abstract: The present invention provides a thermally deformable annular packer with pressure relief means for use in oil and gas wells. The annular packer is formed from a stack of component parts, said parts comprising one or more eutectic alloy based ring sections sandwiched between two end sections. At least one of the annular packer component parts has one or more enclosed voids that are configured to become exposed when the packer is subjected to a predetermined pressure or temperature. The exposure of the enclosed voids serves to increase the effective volume within the sealed region formed by the annular packer in the annulus between two coaxial well casing/tubing. The increase in the effective volume serves to reduce the pressure within the sealed region thus preventing a build-up of pressure that might otherwise have damaged the well casing/tubing.

Abstract: A method of clearing well casing (3) or tubing from a target region of an oil/gas well (1) borehole is provided. The clearance of the oil/gas well bore hole being achieved by employing chemical agents (9) that consume, weaken or melt the well casing/tubing. In some aspects of the method the well casing is cleared to expose the rock formation within which the well borehole is formed so that the rock formation can be accessed from within the well casing/tubing. In other aspects of the method the removal of inner tubing structures is used to facilitate the unimpaired deployment of repair tools down the well borehole.

Abstract: The present invention provides a downhole tool deployment assembly (1) for use in particular in oil/gas wells. The assembly comprises a heater (2) with a tubular heater body having an internal cavity configured to receive a heat source (6). The assembly also has a tubular heat conducting member (3) configured to surround the tubular heater body leaving an annular clearance, wherein the tubular heat conducting member does not extend along the entire length of the tubular heater body. In addition, a collar (4) is mounted adjacent to the region of the assembly where the tubular heat conducting member ends. The collar is configured to prevent access to the annular clearance between the tubular heat conducting member and the tubular heater body. A eutectic/bismuth based alloy (5) covers the collar and at least a portion of the tubular heater body and the tubular heat conducting member such that the alloy holds the heater and the tubular heat conducting member together until the alloy is melted.

Abstract: 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.

Abstract: An oil or gas well downhole fishing tool has a receptacle that is open at one end. The tool also has deployment tool engaging means, located on the opposite end of the receptacle to the one end. The tool further has a layer of an alloy provided on the interior surface of the receptacle. The alloy is a eutectic alloy and/or bismuth alloy. The tool further comprises heating means to heat the alloy so that it melts and can flow over any object received within the receptacle.

Abstract: A first aspect of the invention provides a gas or oil well tubing having an annular packer mounted thereon, wherein the annular packer is formed from an eutectic alloy. By prefabricating the annular packer on the tubing it can be placed in situ from the outset and thus can be active by melting at any time to form a eutectic seal quickly and easily. An annular packer with by-pass conduits is also provided to enable cement to be pumped past the annular packer when it is in situ. The annular packer is further provided with conduit clearance means to clear cement from within the conduits.

Abstract: Apparatus, in the form of a eutectic alloy plug (1) and a deployment heater (10) are provided. The plug (1) and the deployment heated (10) are provided with means (5, 13) for releasably retaining the deployment heater (10) within a cavity (4) in the plug (1). The nature of the retaining means is such that once the plug (1) is secured in a well the heater (10) can be recovered without the plug (1). An extraction heater (20), which is also receivable within the cavity (4) of the plug (1), is provided to re-melt the eutectic alloy and thus enable the extraction of the plug from a well. Various method of plugging abandoned wells are made possible by the control that the provided apparatus gives.

Abstract: The present invention provides a thermally deformable annular packer with pressure relief means for use in oil and gas wells. The annular packer is formed from a stack of component parts, said parts comprising one or more eutectic alloy based ring sections sandwiched between two end sections. At least one of the annular packer component parts has one or more enclosed voids that are configured to become exposed when the packer is subjected to a predetermined pressure or temperature. The exposure of the enclosed voids serves to increase the effective volume within the sealed region formed by the annular packer in the annulus between two coaxial well casing/tubing. The increase in the effective volume serves to reduce the pressure within the sealed region thus preventing a build-up of pressure that might otherwise have damaged the well casing/tubing.

Abstract: 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.

Abstract: The present invention provides a method of sealing a region of a sand screen of an Open Hole Gravel Pack without the need to perforate the sand screen and a tool for use in such. The tool being a eutectic/bismuth based alloy well plugging/sealing tool (1) having a tubular heater body (2) with an internal cavity (4) capable of receiving a chemical heat source (105). The tool is provided with a quantity of eutectic/bismuth based alloy (3) around an outer surface of the heater body (2) such that it can be heated by the chemical heat source (105). In addition the tool (1) has an insulating sleeve (7) provided around an outer surface of the alloy (3), wherein the sleeve (7) is configured to provide a focused egress for the alloy (3) as it is melted by the chemical heat source (105).

Abstract: A downhole tool for use in a gas or oil well is provided. The tool comprising a length of tubing having at least one annular sealing means mounted on the outer surface thereof. The annular sealing means, which are formed from a eutectic/bismuth based alloy, serve to secure the downhole tool in position within an oil or gas well during so that the tool can carry out its function.

Abstract: 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.

Abstract: An oil or gas well fishing tool is provided. The downhole fishing tool has a receptacle that is open at one end. The tool also has deployment tool engaging means, located on the opposite end of the receptacle to the one end. The tool further has a layer of an alloy provided on the interior surface of the receptacle. The alloy is a eutectic alloy and/or a bismuth alloy. The tool further comprises heating means to heat the alloy so that it melts and can flow over any object received within the receptacle.