Terpene-based spotting fluid compositions and processes for freeing differentially stuck pipe are provided. A spotting fluid composition includes a terpene and an acid, such that the acid initiates an exothermic polymerization reaction of the terpene. Another spotting fluid composition includes an invert emulsion having a terpene external phase and a non-miscible organic hygroscopic fluid internal phase. The terpene emulsion spotting fluid composition may be introduced downhole in the vicinity of a portion of a differentially stuck pipe such that the spotting fluid composition contacts a filter cake surrounding the portion of the differentially stuck pipe. An acid may be introduced downhole in the vicinity of a portion of a differentially stuck pipe such that the acid initiates an exothermic polymerization reaction of the terpene of the terpene emulsion spotting fluid composition.

Alkyl ester spotting fluid compositions and processes for freeing differentially stuck pipe are provided. An alkyl ester spotting fluid composition includes an invert emulsion having an alkyl ester as the external phase and water as the internal phase. In some embodiments, the alkyl ester spotting fluid composition may include the alkyl ester invert emulsion and an emulsifier. The alkyl ester spotting fluid composition may be introduced downhole in the vicinity of a portion of a differentially stuck pipe such that the spotting fluid composition contacts the mudcake and frees the differentially stuck pipe.

A downhole separation apparatus for releasing a pipe string from a bottom hole assembly is disclosed. The apparatus has a tubular collet body, a tubular bottom sub, and a piston collet positioned within the collet body. The collet piston has a plurality of collet fingers threadedly engaging an internal profile of the bottom sub. Separation is accomplished by pumping a circulation ball through the pipe string until it lands on a ball seat inside the collet piston. Increasing fluid pressure then shifts the piston collet axially downward within the collet body thereby causing the collet fingers to collapse to disengage the bottom hole assembly from the pipe string.

A downhole separation apparatus for releasing a pipe string from a bottom hole assembly is disclosed. The apparatus has a tubular collet body, a tubular bottom sub, and a piston collet positioned within the collet body. The collet piston has a plurality of collet fingers threadedly engaging an internal profile of the bottom sub. Separation is accomplished by pumping a circulation ball through the pipe string until it lands on a ball seat inside the collet piston. Increasing fluid pressure then shifts the piston collet axially downward within the collet body thereby causing the collet fingers to collapse to disengage the bottom hole assembly from the pipe string.

This invention relates to a junk catcher (2, 2′) releasably connected to a retrievable bridge plug (4, 4′) connectable to a setting tool (6) for joint deployment of bridge plug (4, 4′) and junk catcher (2, 2′) in a borehole (9) or a tubular in the borehole (9). Setting tool (6) extends through a fishing neck (12), a catcher tube (14), a flanged section (16), a valve chamber (18), a closable opening (20) and a portion of a setting sleeve (22, 22′) of junk catcher (2, 2′). Valve chamber (18) comprises a valve (50) arranged to close closable opening (20) after retrieval of setting tool (6) from junk catcher (2, 2′). The junk catcher (2, 2′) is connected to bridge plug (4, 4′) by at least one shear bolt (27, 38). Bridge plug (4,4′) comprises a plug fishing neck (32, 32′) facing junk catcher (2, 2′), and bridge plug (4, 4′) comprises an equalizing channel (71) in a mandrel (7). The equalizing channel (71) extends from a bull nose (41) of bridge plug (4, 4′), and where junk catcher (2, 2′) is provided with a closing sleeve (26, 26′), closing sleeve (26, 26′) is connected to bridge plug (4, 4′) by at least one shear bolt (38, 38′), and closing sleeve (26, 26′) seals at least one equalizing port (73) in mandrel (7) when bridge plug (4, 4′) is set. A method for operating bridge plug (4, 4′) and junk catcher (2, 2′) assembly is also described.

A method of removing a target fish from a wellbore includes preparing a fishing assembly having a magnetized pipe coupled to an end of a work string. The fishing assembly is run into the wellbore, and the magnetized pipe is positioned at an effective position in which a threaded end of the target fish is aligned with a threaded end of the magnetized pipe by magnetic attraction between the magnetized pipe and the target fish. A threaded connection is made up between the threaded end of the target fish and the threaded end of the magnetized pipe. The fishing assembly with the attached target fish is then retrieved from the wellbore to a surface location.

A method of freeing a pipe stuck in a subterranean well can include determining a location of a portion of the pipe stuck in the well, and penetrating and/or heating a sidewall of the pipe portion with a beam of light. A system for freeing a pipe stuck in a subterranean well can include a tool deployed into a portion of the pipe stuck in the well by a differential pressure from a wellbore to a formation penetrated by the wellbore. A beam of light emitted from the tool penetrates the pipe portion. Another method of freeing a pipe stuck in a subterranean well can include determining a location of a portion of the pipe which is biased against a wall of a wellbore by differential pressure, and directing a beam of light to the pipe portion.

A method of freeing a pipe stuck in a subterranean well can include determining a location of a portion of the pipe stuck in the well, and penetrating and/or heating a sidewall of the pipe portion with a beam of light. A system for freeing a pipe stuck in a subterranean well can include a tool deployed into a portion of the pipe stuck in the well by a differential pressure from a wellbore to a formation penetrated by the wellbore. A beam of light emitted from the tool penetrates the pipe portion. Another method of freeing a pipe stuck in a subterranean well can include determining a location of a portion of the pipe which is biased against a wall of a wellbore by differential pressure, and directing a beam of light to the pipe portion.

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.

An unstuck system of stuck drill pipes of a drill string of a drilling apparatus adapted to drilled wells to extract fluids or mud includes a torsion coupling system adapted to disconnect an upper portion from a bottom portion including the stuck drill pipes of the drill string and to transfer a rotation to the unstuck system. The unstuck system includes at least an axial forced vibration generator including at least one axially movable element adapted to generate at least a vibration which is propagated to pipes of a portion free from being stuck, where the induced vibrations fall within a band of induced frequencies near or corresponding to a resonance frequency of the portion free from being stuck.