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.

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.

A method of plugging a hydrocarbon well includes deploying a downhole tool to remove at least a portion of a casing at a section of well to be plugged. Then a plugging material is put downhole onto a blocking device to fill an area to be plugged. An exothermic fluid is added, wherein activation of the exothermic material liquefies the plugging material. Allowing the plugging material and the exothermic fluid to solidify form a cast-in-place plug that fills the section of well to be plugged.

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.

Methods to repair leaking liner hangers and/or drop off liner assemblies utilizing heaters to melt metal alloys which will solidify and form an annular seal at the liner hanger and seal the leak. Such methods may be used in numerous liner hanger environments, including but not limited to, well bores with and without tieback assemblies.

A system, method and apparatus for creating an electric glow discharge includes a non-conductive housing having a longitudinal axis, a first opening aligned with the longitudinal axis, and a second opening aligned with the longitudinal axis and opposite the first opening, a first electrically conductive screen disposed proximate to the first opening of the housing and substantially perpendicular to the longitudinal axis, a second electrically conductive screen disposed proximate to the second opening of the housing and substantially perpendicular to the longitudinal axis, wherein the second electrically conductive screen separated from the first electrically conductive screen by a substantially equidistant gap, a non-conductive granular material disposed within the substantially equidistant gap, and the electric glow discharge is created whenever the first electrically conductive screen has a first polarity, the second electrically conductive screen has a second polarity, and an electrically conductive fluid is introduced into the substantially equidistant gap.

Methods for initiating chemical reactions in a wellbore include delivering one or more reactive components via a carrier fluid to the wellbore. The one or more reactive components delivered to the wellbore are configured to enable one or more chemical reactions to occur. The one or more chemical reactions are carried out until a threshold volume of the one or more reactive components is delivered to the wellbore.

Methods including generating heat and/or gas in subterranean operations, pipelines, and other related applications. In some embodiments, the methods include providing treatment composition including a carrier fluid, a catalyst, a first reactant, a second reactant, a solvent, an emulsifier, and a foaming agent, wherein the first and second reactants are capable of reacting in an exothermic chemical reaction; and introducing the treatment composition into at least a portion of a conduit or container having a temperature of less than 30° C.

A well cleanup process involves removing an impermeable filter cake from a formation face with thermochemical and chelating agents to allow formation fluids to flow from a reservoir to a wellbore. The method may be used with oil and water-based drilling fluids with varied weighting agents, e.g., bentonite, calcium carbonate, or barite. Such thermochemical agents may involve two salts, e.g., NO.sub.2.sup.− and NH.sub.4.sup.+, which, when mixed together, can generate pressure and heat, in addition to hot H.sub.2O and/or N.sub.2. For example, the thermochemical agents may comprise Na.sup.+, K.sup.+, Li.sup.+, Cs.sup.+, Mg.sup.2+, Ca.sup.2+, and/or Ba.sup.2+ with NO.sub.2.sup.− and NH.sub.4.sup.+ with F.sup.−, Cl.sup.−, Br.sup.−, I.sup.−, CO.sub.3.sup.2−, NO.sub.3.sup.−, ClO.sub.4.sup.−, and/or .sup.−OH. The thermochemical agents in combination with a chelator such as EDTA can removed the filter cake after 6 hours with a removal efficiency of 89 wt % for the barite filter cake in water based drilling fluid, exploiting the generation of a pressure pulse and heat which may disturb the filter cake and/or enhance barite dissolution and polymer degradation.

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.