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.

An apparatus that includes a material that holds a release section in an engaged position. The apparatus also includes a heat source to change the phase of the material, allowing the release section to move to a disengaged position.

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.

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.

A welding tool consisting of a tubular body having a lateral end and a pin end. The pin end has external threads disposed around an external circumferential surface of the pin end. The lateral end comprises an inner wall defining an orifice. Additionally, a heat proof shell is disposed circumferentially around the lateral end. The welding tool further includes a battery housing. The battery housing encloses a plurality of batteries which store energy. The welding tool further includes a welding element disposed on an inner surface of the orifice and an electric line. The electric line is coiled within the tubular body and physically contacts the welding element and is electrically connected to the plurality of batteries. The welding tool further includes a controller. The controller is capable of receiving and parsing mud pulse signals and controlling the release of stored energy from the batteries to the electric line.

An apparatus can include a cable head assembly with a cable head stinger connected to a weak link, and a release assembly including a bushing that radially outwardly supports a dog in engagement with an internal groove formed in an outer housing. A method can include connecting a bottom hole assembly to a wireline, the connecting including connecting the wireline to a cable head stinger of a cable head assembly; deploying the wireline and bottom hole assembly into the well; applying a tensile force to the wireline, thereby breaking a weak link of the cable head assembly; and then displacing the cable head stinger into engagement with a bushing of the release assembly, thereby permitting a dog to displace radially inwardly out of engagement with an internal groove in the release assembly.

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.

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.

An oil or gas well fishing tool (60). The downhole fishing tool (60) has a receptacle (61) that is open at one end. The tool also has deployment tool engaging means (62), located on the opposite end of the receptacle (61) to the one end. The tool further has a layer of an alloy (64) provided on the interior surface of the receptacle (61). The alloy is a eutectic alloy and/or a bismuth alloy. The tool further comprises heating means (65) to heat the alloy (64) so that it melts and can flow over any object received within the receptacle (61).

A downhole tool for joining a string of pipe to a tubular already downhole with a seal element made of metal or metal alloy with a melting point lower than the melting point of the tool and tubular but higher than the temperature of expected downhole operating conditions.