A pipe-in-pipe bulkhead assembly has inner and outer rings spaced in concentric relation to define a thermally-isolating gap in the annulus between them. Interlocking formations project into the annulus from each of the rings, presenting confronting faces where they overlap radially. The gap extends between the longitudinally-spaced faces. A thermally-insulating spacer is interposed between the faces in the gap to carry axial mechanical loads between the inner and outer rings. Heating elements outside the inner ring extend longitudinally beyond the gap between the faces and along a longitudinal passageway that passes through or beside an interlocking formation of the inner ring. The spacer may be positioned before or after the outer ring is placed, for example as a discrete element or as an injected mass. An additional sealing mass may also be positioned in the annulus, for example by injection, to promote a gas-tight seal.

A subsea hydrocarbon production field includes a number of first subsea Christmas trees, a first manifold and a number of first flexible flowline jumpers, each of which is connected between the first manifold and a corresponding first tree. In one embodiment, Each first flowline jumper includes a first flow conduit and a number of first umbilical lines.

Obstructing fluid plugs are removed from a base section of a riser, which base section extends between a receiving end connected to an upright section of the riser and an emitting end of the riser connected to a subsea template located on a seabed over a drill hole to a subterranean void into which fluid received via the riser is to be injected from the subsea template (120). The obstructing fluid plugs are removed either by injecting heated assisting from a storage container into an injection point in the base section and injecting heated assisting liquid from the vessel in the upright section of the riser, or a heating unit is controlled to heat the base section to a predetermined temperature, and thereafter maintain a temperature level here above or equal to the predetermined temperature.

The invention relates to a subsea heating apparatus for heating a subsea component extending along a longitudinal direction, comprising an induction coupler including a first section with first core part(s) and a second section with second core parts, a respective first magnetic core part being coupled with a second magnetic core part to form a magnetic core ring adapted to surround an electrical conductor to be connected to a power source. At least one component electrical cable associated with the subsea component to be heated and adapted to receive power via the induction coupler for heating the subsea component. The coupler includes several windings each wound around a respective second core part and connected to respective component electrical cable(s). The second section is adapted to be attached to the subsea component and several second core parts are arranged in distinct radial positions around the longitudinal direction.

A method of sealing an annulus of an electrically trace-heated pipe-in-pipe structure including introducing a flowable filler material to mold a sealing mass in situ is disclosed. The sealing mass closes a restriction at which the annulus is narrowed radially and embeds at least one heating element that extends generally longitudinally through the restriction. The structure includes an inner ring spaced within an outer ring to define the annulus between the rings. The annulus is narrowed radially by one or more projections that extend radially into the annulus from at least one of the rings toward the other of said rings. The restriction may include multiple bores, each of which may contain a sealing mass around a respective heating element in the bore.

A method of sealing an annulus between inner and outer pipe sections of a pipe-in-pipe system includes positioning a sealing mass in the annulus in contact with the inner and outer pipe sections. Deforming the sealing mass occurs, for example by shearing and compression, by effecting relative longitudinal movement between the inner and outer pipe sections. Fixing the inner and outer pipe sections against reverse relative longitudinal movement to maintain deformation of the sealing mass is then performed. The inner pipe section and a displaced outer pipe section may be fixed by welding them to respective pipes of an adjoining pipe-in-pipe structure. Opposed ramp surfaces, each being similarly inclined relative to the longitudinal direction, extend into the annulus from respective ones of the pipe sections such that the sealing mass may be compressed between the ramp surfaces.

A hydrocarbon heating system for a hydrocarbon production and/or transportation system comprising at least one electrical conductor and an alternating current (AC) power source connected to the at least one electrical conductor. The alternating current power source generates heat in the at least one electrical conductor by providing alternating current power to the at least one electrical conductor.

A method of mitigating formation of an undesired accumulation of a substance in a well tool through which a well fluid flows can include heating a surrounding wall of an interior flow passage through which the well fluid flows. A system for of mitigating formation of an undesired accumulation of a substance in a well tool can include an interior flow passage having a surrounding wall, and a heater which heats the wall of the flow passage. Another method of mitigating formation of an undesired accumulation of a substance in a well tool can include monitoring the accumulation of the substance in the well tool, and heating a surrounding wall of an interior flow passage in response to detecting the accumulation.

Methods, apparatus and systems for in-situ heating fluids with electromagnetic radiation are provided. An example tool includes a housing operable to receive a fluid flowed through a flow line and a heater positioned within the housing. The heater includes a number of tubular members configured to receive portions of the fluid and an electromagnetic heating assembly positioned around the tubular members and configured to generate electromagnetic radiation transmitted to heat the tubular members. The heated tubular members can heat the portions of the fluid to break emulsion in the fluid. Upstream the heater, the tool can include a homogenizer operable to mix the fluid to obtain a homogenous fluid and a stabilizer operable to stabilize the fluid to obtain a linear flow. Downstream the heater, the tool can include a separator operable to separate lighter components from heavier components in the fluid after the emulsion breakage.

An exposed resistive heating element is coupled to an electric power supply. The exposed resistive heating element is malleable such that it can be wrapped around a component to be heated. A controller is coupled to the power supply and the exposed resistive heating element. The controller is configured to regulate current exchanged between the exposed heating element and the electric power supply.