The invention relates to the introduction of pressurized fluid, e.g. acid, into a subsea well directly from a vessel (33). A fluid injection assembly (20) is fitted to the top of a subsea Xmas tree (3), the assembly (20) including fail safe closed valve (21) which is controlled via a hydraulic line (31) from the vessel. The hose and assembly and valve are designed with an internal bore allowing a large diameter ball to be dropped (required for acid stimulation). The subsea subsea control module (8) on the Xmas tree is controlled from the producing platform.

A subsea catenary riser comprises a rigid riser pipe that is suspended from a floating support on the surface and extends through a sagbend to the seabed. A hang-off interface allows rotation or pivoting of the riser pipe relative to the support about mutually orthogonal horizontal axes. A subsea buoy is positioned on the riser pipe above the sagbend. The buoy applies buoyant upthrust force to the riser pipe via an attachment interface that allows rotation or pivoting of the riser pipe relative to the buoy about mutually orthogonal horizontal axes. In response to movement of the support, the riser pipe deflects with S-shaped curvature to vary the inclination, relative to the buoy, of the portion of the riser pipe to which the buoy is attached. The curvature comprises mutually opposed curves respectively above and below the buoy, joined by a region of inflection that coincides with the buoy.

A method approximates and connects an off shore riser duct to a floating unit, includes installing a tubular coupling recipient on the floating unit at a riser coupling level, the coupling recipient having an annular side wall extending around a longitudinal axis. A pulling device is on the floating unit at a pulling device level above the riser coupling level. The pulling device pulls a line extended through the coupling recipient and connected to a pulling head at a riser duct upper end. The riser duct upper end is pulled into the coupling recipient, providing a locking mechanism to lock a coupling adapter against downward withdrawal. Extending the line along a curved deviating surface deviates the pulling direction. The curved deviating surface is formed by a deviating member connected to the coupling recipient at a distance from the longitudinal axis smaller than an annular side wall to longitudinal axis distance.

The present disclosure provides a system and a method for efficiently converting the structure of a drilling floating platform into a structure for a production floating platform. A riser support module can be coupled to a topsides of the drilling floating platform and suspended below a moonpool or other opening through the topsides to support risers and their respective riser pull tubes, if any. The riser support module can be prebuilt and installed as a unit for example at a quayside.

An apparatus enables modifying a riser's operating parameters for transporting production fluids from a subsea well to an offshore production facility after an initial period of production to address changes over time in the conditions of the reservoir and/or the riser without removing the original riser. An insert riser having a smaller diameter is inserted into the riser after the initial period. The original riser has a recessed seal face for receiving seal element(s) and a recessed lock groove for receiving a locking ring. An intervention coiled tubing having a sleeve removal tool is inserted into the riser to engage a protective sleeve covering the recessed seal face. The tubing is pulled to the floating structure thereby removing the protective sleeve and the temporary retaining ring from the production riser, exposing the recessed seal face. The insert riser can then be inserted into the riser and locked into place.

An extension member for coupling a tapered stress joint to a basket coupled to a porch extending from an offshore platform is disclosed. In an embodiment, the extension member includes a central axis, a first end, and a second end opposite the first end. In addition, the extension member includes a radially inner surface extending axially from the first end to the second end. The inner surface includes a first mating profile proximate the first end that is configured to engage a radially outer surface of the tapered stress joint. Further, the extension member includes a radially outer surface extending axially from the first end to the second end. The outer surface includes a second mating profile proximate the second end that is configured to slidingly engage a mating profile within the basket.

Pipelines with a control system and forced circulation of fluids through the annulus between an inner barrier and an outer cover of a pipe use a system configured to force circulation of fluids through the annulus. The pipe includes segments (T1, T2, T3, TN) joined together by means of connectors, wherein each segment of the pipe has an injector pipe (I1, I2, I3, IN) for injecting fluid into the annulus at a first end of the segment, and a return pipe (R1, R2, R3, RN) for removing fluid from the annulus at a second end of the segment.

The present invention relates to a method for operating a drilling vessel adapted to run large diameters surface casing joints having a diameter of over 20 inch (51 cm) and a length of 30-50 feet (9-15 meters), and build a surface casing string. According to the invention three or more surface casing joints are interconnected into pre-assembled surface casing stands having a length of over 100 feet (30 meters). These surface casing stands are substantially horizontally stored and transferred by a casing stand handling system to a surface casing string handling capacity hoisting device, which subsequently lowers the surface casing string.

A fluid handling system comprising an annular sealing device and a flow control system to divert fluid flow from an annulus of a riser package to a control system located on a rig. A method of installing a fluid handling system on a riser package from a rig comprises connecting the fluid handling system to an upper end of a riser string, supporting the fluid handling system and the riser string using a first tubular handling device, and lowering the fluid handling system and the riser string to an operating position.

A vessel is adapted to perform subsea wellbore related operations involving a riser string between the subsea wellbore and the vessel, e.g. drilling and/or wellbore intervention. The vessel includes a hull having a deck, and a riser storage hold present within the hull below the deck. The riser storage hold includes storage racks adapted to store therein parallel stacks of multiple riser sections and/or pre-assembled riser stands in horizontal orientation. The vessel has an elongated riser transfer opening between the deck and the roof, the riser transfer opening extending in a direction parallel to the storage racks, the riser transfer opening having a length and a width so as to allow for transfer of a single riser section or a single riser stand in horizontal orientation via the riser transfer opening out of and into the riser storage hold, wherein the risers' handling system is suitable to work at the same time with two different lengths.