Described examples relate to a downhole fluid heater, comprising a fluid heating assembly comprising a heating chamber for receiving a fluid. The fluid heating assembly is configured to agitate a heat transfer fluid in the heating chamber so as to impart thermal energy and heat the heat transfer fluid.

A system for supporting a borehole junction includes a device configured to deploy a material in a solid state to a downhole location proximate to the borehole junction, and a heat source configured to apply heat to the material to a temperature sufficient to liquefy the material. The liquified material is configured to flow into a formation region adjacent to the borehole junction and consolidate the formation region.

A method for forming a sleeve for wrapping around and insulating a joint of a downhole tubing string is provided. The method includes the steps of providing a mold, applying insulation around the mold, winding an interfacing material around the insulation; and applying a polymer onto the interfacing material to bind to the interfacing material to form the sleeve.

A tubular for downhole use, the tubular including a pipe, an insulation layer surrounding the pipe, and a protective layer around the insulation layer and comprising a polymer. The protective layer can also include a compression layer adjacent to the insulation layer. There may be reinforcement material in the protective layer, for example encapsulated by the elastomer. The tubular may have bare portions at the ends for manipulation of the tubulars to form a tubing string. A sleeve may be provided using the same layer structure to insulate the bare portions which form joints of the tubing string. The sleeve can also include a base layer.

Embodiments comprise a method of removing material at a well, involving progressively jetting heat along a helical path to heat a target material for removal. Embodiments of the method comprise material removal from a downhole well element, involving running in a downhole assembly with a downhole heating device comprising a fuel towards a target location. For example, such embodiments provide an alternative method for the removal of wellbore tubulars, using a rapid oxidation process to significantly alter the physical state of the tubular well element and reduce it to an oxide deviate, thereby facilitating an area where a more conventional barrier can be installed in the wellbore.

Embodiments comprise a method of removing material at a well, involving progressively jetting heat along a helical path to heat a target material for removal. Embodiments of the method comprise material removal from a downhole well element, involving running in a downhole assembly with a downhole heating device comprising a fuel towards a target location. For example, such embodiments provide an alternative method for the removal of wellbore tubulars, using a rapid oxidation process to significantly alter the physical state of the tubular well element and reduce it to an oxide deviate, thereby facilitating an area where a more conventional barrier can be installed in the wellbore.

The present invention relates to a system for facilitating the extraction of hydrocarbons. Tubular protection for an extraction system is provided using the RF heating of highly viscous hydrocarbons in situ by means of an antenna having a coaxial array of mode converters.

Downhole apparatus comprises: a tubular body for mounting on an inner tubing string (10); a first flow port (24); a second flow port (12a); and a connector (68) associated with the tubular body (10) and operable to at least one of engage with and disengage from a lower end (22) of a bore-lining tubing string (20). The apparatus has a first configuration in which the first flow port (24) is open and the second flow port (12a) is closed, whereby a settable material (54) may be pumped in a first direction (56) downwards through the tubular body, through the connector, and through the first flow port, and a second configuration in which the first flow port (24) is closed and the second flow port (12a) is open, whereby a fluid may be pumped in the first direction (58) downwards through the tubular body (10), exit the tubular body through the second flow port (12a), and then flow in a second direction upwards and externally of the tubular body.

Systems and methods for increasing hydrocarbon production using an electrical submersible pump are described. The methods typically include, for example, configuring an electrical submersible pump comprising a gas separator to induce a gas lift effect in a well comprising a tubing within a casing. Hydrocarbon production from the well is therefore increased using the electrical submersible pump.

A device for heating oil and for reducing viscosity of the oil in an oil well is disclosed. The device comprises a pipe structure, a sucker rod, a three-way connector, a small pump cylinder, a small plunger, and a heating mechanism. The three-way connector is located below the pipe structure and has an upper end and two lower ends. The upper end of the three-way connector is connected to a bottom end of the pipe structure, and the two lower ends of the three-way connector comprises a first lower end which is coaxial with the oil pipe and a second lower end which is non-coaxial with the pipe structure. The first lower end of the three-way connector is connected to the small pump cylinder which is coaxial with the pipe structure. The second lower end of the three-way connector comprises a bypass port and a check valve. The sucker rod extends inside the pipe structure and extends through the upper end and the first lower end of the three-way connector and extends to a bottom end of the small pump cylinder. A bottom end of the sucker rod is provided with a small plunger, and the small plunger and the small pump cylinder constitute an axial sliding sealed fit. The heating mechanism extends along the sucker rod to the bottom end of the sucker rod to provide heating to crude oil in the oil well.