Abstract: A method is disclosed for controlling pressure in a wellbore during drilling. The method includes operating a drilling system to have a first fluid pressure gradient inside a drillstring extending from the earth's surface to a drill bit at the bottom of the wellbore. The drilling system has a second fluid pressure gradient lower than the first fluid pressure gradient in an annular space between the drillstring and the wellbore from a selected depth in the wellbore to the earth's surface. Introduction of drilling fluid to the inside of the drillstring is stopped, and fluid flow in the annular space from a point below the selected depth to a point above the selected depth is selectively controlled to cause a substantially constant fluid pressure at a predetermined depth in the wellbore.

Abstract: Two types of isolation tools are disclosed for installation between the upward end of the LMRP and the lower end of a riser string in the drilling of a subsea well using dual gradient techniques, one of which is especially adapted for rotation about a rotating drill sling. Each type includes insert packer adapted to be closed about the drill string to divert drilling fluid in the annulus between the drill string and the subsea wellhead into lines extending along the side of the riser to the surface. The insert is selectively removable to permit conventional drilling.

Abstract: A wellhead assembly has an inner wellhead that lands in an outer wellhead, the inner wellhead having first and second internal passages. Each passage has an upper opening at the outer surface of the inner housing and a lower opening at the inner surface. An external shoulder of a casing hanger lands on an internal shoulder of the inner housing, the lower opening of the first passage being below the internal shoulder, the lower opening of the second passage being above the internal shoulder. The casing hanger has a substantially-vertical passage located in its sidewall, an upper port registering with the lower opening of the second passage, a lower port being located below the external shoulder for communicating with the annulus. Valve assemblies at the upper openings control the flow of heavy fluid injected into a casing annulus through the second passage and of cuttings injected into the annulus through the first passage.

Abstract: A drill cuttings injection system injects cuttings from drilling a well into a wellhead assembly. The wellhead assembly has a tubular housing mounted to an upper end of a well and a casing hanger concentrically located in the housing, defining an annular clearance. A port extends through the housing for injecting a stream of drill cuttings into the annular clearance. A sleeve is mounted in the port. The sleeve has a cylindrical sidewall and an inner end containing a deflection plate. The sleeve has an aperture in the sidewall adjacent the deflection plate for discharging the stream after the stream contacts the deflection plate. The deflection plate protects the casing hanger from erosive contact with the stream.

Abstract: A method of drilling an offshore underwater well comprising the steps of installing a riser conduit so that it is substantially vertically supported at a production deck. The riser conduit deviates progressively further from the vertical with increasing sea depth, so that its end can be anchored at the seabed by a skid either at an oblique angle so that drilling into the seabed can be carried out at the oblique angle, or horizontally, so that the riser conduit can extend some considerable distance across the seabed before drilling is carried out.

Abstract: A method is provided for eliminating the presence of micro-annuluses associated with a subsea hydrocarbon producing wellbore for accurate gathering of data within the subsea hydrocarbon producing wellbore. The method involves using a sea floor pressure head assembly in conjunction with a subsea blow out preventer, where the sea floor pressure head assembly has an elongated tube with a stop ring formed thereon and an ambient pressure side. The blow out preventer is connected to the entrance of the subsea hydrocarbon producing wellbore, and includes an inflatable bladder and is connected to a hollow riser connected thereto.

Abstract: A christmas tree to control the production from a subsea oil or gas well is disclosed. The christmas tree design including a tree body having a first flow port and a tree cap; a tubing hanger landed within the tree body; an actuation mandrel landed within the tree body, the actuation mandrel having a flow port; and a flow diverter disposed within the tree cap to divert flow through the flow port. The christmas tree arrangement allows for dual barriers within the tree cap without placing or retrieving any plugs from within the tubing hanger, thereby reducing the number of downhole trips required to complete and/or service the subsea well.

Abstract: A riser connector is provided for connecting a riser to a wellhead assembly having a bore therethrough. The connector includes a housing having a first and a second end. The first end of the housing has an opening and is adapted for mounting to the wellhead assembly with the opening in communication with the bore of the wellhead assembly. The second end has a first opening connectable to the riser having a diameter at least the same as the inner diameter of the riser, and a second opening, having a diameter at least substantially the same as the diameter of the bore of the wellhead assembly. The housing further includes a first conduit connecting the opening in the first end of the housing to the first opening in the second end of the housing, and a second conduit connecting the opening in the first end of the housing to the second opening in the second end of the housing. In use, first well operations are conducted through the riser in the conventional manner.

Abstract: The present invention embodies a temperature control device for preventing the formation of alkane hydrates in a subsea oil and gas production equipment component having at least one flow path through which a well fluid is permitted to flow, the well fluid having a flow temperature and a lower hydrate formation temperature at which hydrates will form in the well fluid, the temperature control device comprising a housing positioned in heat exchange relation with respect to the flow path and a phase change material disposed in the housing, the phase change material having a melting point which is below the flow temperature but above the hydrate formation temperature, whereby when the temperature of the phase change material drops to its melting point, the phase change material will solidify and its latent heat will be transferred to the well fluid to maintain the temperature of the well fluid in the flow path above its hydrate formation temperature.

Abstract: A mounting device for mounting a Christmas tree on a wellhead at sea, for use during a lowering of the Christmas tree from a platform to a drilling template which is located on the seabed. The mounting device includes an adaptor with end sections for connection with respective sections of the drilling template and the Christmas tree. The end sections of the adaptor have alignment bodies which are arranged for engagement with coacting alignment bodies of the drilling template and the Christmas tree.

Abstract: The present invention is directed to a sealing sleeve which is disposed in a lateral fluid conduit that extends at least partially through a tubing hanger and a surrounding spool and which is slideable between a retracted position for running and retrieval of the tubing hanger and an extended position for sealing across the interface between the tubing hanger and the spool.

Abstract: Two types of isolation tools are disclosed for installation between the upward end of the LMRP and the lower end of a riser string in the drilling of a subsea well using dual gradient techniques, one of which is especially adapted for rotation about a rotating drill sling. Each type includes insert packer adapted to be closed about the drill string to divert drilling fluid in the annulus between the drill string and the subsea wellhead into lines extending along the side of the riser to the surface. The insert is selectively removable to permit conventional drilling.

Abstract: A subsea well apparatus has features for controlling and monitoring production fluid flow from a well. A Christmas tree lands on a subsea wellhead, the tree having a tubular, open upper end. A first flow passage extends from a lower end of the tree to the upper end for communicating fluid with the well. A second flow passage extends downward from the upper end of the tree and has an outlet on a sidewall of the tree for communicating with a flowline. A production module lands on and is retrievable from the upper end of the tree, the module having a flow loop with one end in communication with the first flow passage and another end in communication with the second flow passage. At least one flow interface device is located in the loop of the production module. The flow interface device may be used to monitor or control the flow and may be a temperature or pressure sensor, a flow or multi-phase flow meter, or a choke.

Abstract: A wellhead assembly comprises a central bore through the wellhead assembly having a pressure boundary region. A port is provided in the wellhead assembly having an opening in the central bore in the pressure boundary region of the wellhead assembly. The port preferably extends through the high pressure housing into the bore of the wellhead assembly. A first casing string is secured at a first end within the wellhead assembly below the opening of the port in the central bore of the wellhead assembly. A second casing string is secured at a first end within the wellhead assembly above the opening of the port in the central bore of the wellhead assembly. A fluid flowpath is thereby formed comprising the port in the wellhead assembly and an annulus between the first and second casing strings. In this way, access is provided to an annulus within the well.

Abstract: An injection spool for use in the injection of a fluid, for example a slurry of drilling cuttings, into a subsea wellhead assembly has an outer housing having a central bore therethrough. The housing has a first end for connection to a wellhead assembly such that the central bore of the housing is aligned with the central bore of the wellhead assembly. An inner housing, for example an isolation sleeve, having a central bore therethrough is disposed within the central bore in the outer housing, whereby a cavity is formed between the inner housing and the outer housing. A port in the outer housing has an opening into the cavity between the inner housing and the outer housing, through which a fluid may be injected. The inner housing has a portion extending from within the outer housing beyond the first end of the outer housing for forming a cavity within a wellhead assembly to which the injection spool is connected.

Abstract: A drill bit guide is mounted in a wellhead in place of a wear bushing. The bit guide is capable of guiding strings and tools through the wellhead without damage to the wellhead or string while drilling. In one version of the bit guide, a pair of linear actuators radially extend and retract separate halves of the bit guide to conform to the size of the object located between them. In another version of the bit guide, a set of interlocking arms and wear bars are articulated to form a circular opening having a variable inner diameter. A drill string may be lowered through a fully open bit guide or landed on top of a filly closed bit guide. The bit guide also can be moved to more closely receive the drill string passing through it to prevent damage to the drill string and the wellhead.

Abstract: A drill cuttings injection system for a well with a wellhead housing and a casing hanger supported in the wellhead housing. The wellhead has an axial flow port with an upper end in communication with an outer surface of the housing and a lower end in communication with an inner surface of the housing. An injection ring is positioned on the wellhead housing and has an external port. The injection ring defines an annular gallery in communication with the upper end of the axial flow port. A cuttings injector is adapted to land on the injection ring and has a hydraulic passageway sealable to the external port through which drill cuttings can be pumped into the well.

Abstract: A shallow water flow subsea drilling system is disclosed. A wellhead system is provided with a 36″ conductor pipe in which a 26″ casing and 26″ wellhead housing are landed. The 26″ casing extends to a depth above a shallow water flow zone. A borehole through the shallow water flow zone is sized to accept a 20″ casing to the top of which is secured an 18¾″ wellhead housing. An annulus between the 26″ and 18¾″ housings communicates with cement returns from the 20″ casing. Flow-by holes in the 26″ wellhead housing are sealed with a retrievable seal assembly and actuating mechanism run on the same running tool with the 20″ casing and 18¾″ wellhead housing. A hydraulic feedback mechanism is provided to sense at the service vessel whether or not the seal assembly has been correctly positioned in the annulus.

Abstract: A slot lock ring assembly capable of repeated radial expansion and contraction without sustaining permanent deformation and expansion to a load bearing state comprising: a solid metal ring having a toothed profile on one diameter and a tapered actuating profile on the opposite diameter, a top edge and a bottom edge; a spaced group of cuts that allow repeated radial expansion and contraction of the solid metal ring without sustaining permanent deformation, wherein the cuts are made in an alternating pattern, of a first cut starting on the top edge followed by a second cut starting on the bottom edge, and each group of cuts is spaced apart 10 to 40 degrees.

Abstract: A method of lowering items from a drilling rig to a well located below it through the use of a landing string comprised of drill pipe having an enlarged diameter section with a shoulder, in combination with upper and lower holders having wedge members with shoulders that engage and support the drill pipe at the shoulder of the enlarged diameter section.

Abstract: A concentric tubing hanger having a radially offset tubing annulus passage closeable by a remotely operable valve, preferably a pressure balanced, hydraulically-operated shuttle valve positioned at an upper end of the tubing annulus passage. The tubing hanger is of relatively compact design, accommodating a large diameter production bore and a large number of downhole service lines. Service line couplers and outlet ports of the valve are housed in a void defined between the tubing hanger and a seal stab assembly of a subsea Christmas tree. The couplers are bathed in an annulus fluid. A tubing hanger running tool has a slot and an orientation helix which cooperate with a key projecting into the production bore to provide passive orientation between the tubing hanger rubbing tool and tubing hanger. A subsea Christmas tree has an annulus flow conduit having a deviated portion, allowing room in a tree block for a bypass conduit and a valve.

Abstract: A ball valve assembly has a lower support, an upper seat, a spherical ball, and linkages for rotating the ball. The lower support has a spherical support surface for the ball. The lower support also has a pair of guides for maintaining alignment of the ball and seat to prevent contact with the linkages. The upper seat has a skirt with a spherical inner surface having grooves for contacting the ball. The skirt and grooves seal and ensure alignment of the ball. The grooves also assist in the retention of lubricant to reduce friction. An optional insert is located in the skirt for low pressure sealing from below and above. Finally, the skirt has a pair of openings to provide relief for the operating links, and flat structures against which the guides of the lower support may restrain rotation of the upper support.

Abstract: The disclosure defined by this invention is a method and assembly for conducting wireline operations in a deep, subsea location, which includes providing a rig on the surface of a body of water, having a riser extending from the rig floor to the floor of the deep body of water; a hydril positioned on the end of the riser on the sea floor; a plurality of blowout preventers positioned below the riser to prevent a blowout into the riser; a wireline subsea blowout preventer control head assembly lowered into the riser to the level above the hydril; pressuring off the assembly by the riser and blowout preventers; lowering a wireline down the riser into the assembly, so that the tool may be lowered beyond the blowout preventers to conduct wireline operations; and pressuring off the side entry apparatus, so that should a blowout occur during wireline operations, any pressure would be prevented from entering the riser, but would be contained by the side entry assembly.

Abstract: A subsea well uses a shuttle valve for connecting tubing annulus passageways between a riser and a tree of a subsea well. The riser has a connector that lands on an upper end of a tree. The riser connector has a production passage and an annulus port. An internal tree cap is located within the tree. A production passage passes through the internal tree cap and an annulus passage communicates with a top surface of the internal tree cap and the annulus passage of the tree. The shuttle valve is located within a valve receptacle or valve cylinder in an upper end of the annulus passage. A portion of the shuttle valve extends above the upper surface of the internal tree cap so that the shuttle valve opens when the riser connector lands on the top of the internal tree cap. Alternatively, the shuttle valve may be hydraulically actuated.

Abstract: A drill pipe handling apparatus for oil and gas drilling rigs, the drill pipe having an enlarged diameter section positioned between the ends of the drill pipe. The enlarged diameter section of drill pipe has a shoulder which corresponds with and is engaged by a shoulder located on wedge members of lower and upper holders on a drilling rig for supporting the drill pipe without damaging it during and after addition or removal of joints of drill pipe.

Abstract: A subsea wellhead and completion system which provides for monitoring pressure in the annulus of the production casing through communication passages that are pressure-isolated from tubing annulus passages and production fluid passages. The communication passages route production casing annulus fluid pressure from the production casing annulus through the production casing hanger to a communication passage provided between the wellhead housing and an isolation sleeve that spans and seals between the production casing hanger and the tree and then through the tree to an outlet on external diameter of the tree and thence to monitoring equipment located typically at the rig. A removable closure member is located in the production casing hanger to isolate the communication passage during drilling operations. This closure member is removed after drilling operations are concluded and after the tree is installed, but before the isolation sleeve and tubing hanger are landed.

Abstract: A subsea completion having an in-line Christmas tree received within a wellhead. The in-line Christmas tree having at least one valve closure element, for example valve gates. Valve actuator couplings, for example push rods are operatively engaged with the valve closure elements and extend through walls of the in-line Christmas tree and wellhead. Relatively bulky valve actuator mechanisms may therefore be mounted externally of the wellhead, with only the relatively small and unobtrusive actuator couplings extending into the wellhead and tree interiors. The in-line tree is used together with a jumper module, secured and sealed to the wellhead, and a separate flow control package.

Abstract: A tubing hanger to facilitate production tubing annulus access including a tubing hanger body having a central bore, a shuttle valve slidably mounted to the tubing hanger body, and at least one annulus access bore through the tubing hanger permitting fluid communication between the central bore and an annulus defined between a production tubing string and a wellbore or casing via the tubing hanger body and the shuttle valve. The shuttle valve may be slidingly movable between an open and a closed position. The tubing hanger may further include a groove enclosed by a filler, the groove providing communication between a plurality of small annulus access bores and a large annulus access bore.

Abstract: A drill pipe for oil and gas drilling rigs, the drill pipe having an enlarged diameter section positioned between the ends of the drill pipe. The enlarged diameter section of drill pipe has a shoulder which corresponds with and is engaged by a shoulder located on wedge members of a holder in a drilling rig for supporting the drill pipe without crushing or otherwise damaging the drill pipe.

Abstract: A device for supplying hydraulic pressure to one or more hydraulically actuable components in a well production system and positioned within the well bore including a reservoir, and electrically powered pump, and a controller each positioned within the well bore and carried on the component. The controller operates the pump to supply fluid from the reservoir to actuate the components. Additionally, valves to route the fluid to the components and sensors to sense when the components are actuated are included.

Abstract: A subterranean oil or gas well apparatus is provided. The apparatus includes a single-bore production tubing hanger arranged concentric with a wellhead. The tubing hanger includes a plurality of ports and channels arranged about the tubing hanger to give operators access to the production tubing annulus and provide chemical injection capability. The ports are closable by a sliding valve. The apparatus also includes annulus and production radial-bore stab assemblies between a christmas tree and an internal crossover assembly. The stab assemblies are extendable and retractable between the chirstmas tree and the crossover assembly to allow the retrieval and installation of each independently.

Abstract: The invention is a device for eliminating the “tripping” of the BOP stack to the surface when switching between drilling and completion modes of operation on a drilling rig. This device is a new apparatus for attaching a BOP guide funnel, which will allow the funnel to be released and/or reattached while the BOP remains subsea on or near the seafloor. The new BOP guide funnel assembly consists of three basic components: a guide funnel, a connector shroud and a parking pile adapter. The guide funnel has a downwardly opening funnel on bottom (used to capture a wellhead) and an upwardly opening smaller funnel on top (used to guide the shroud back into the guide funnel during re-installation of the guide funnel). The connector shroud is permanently attached to the bottom of the BOP stack, surrounding the BOP wellhead connector and holds the guide funnel in place.

Abstract: A flow completion system for controlling the flow of fluid from a well bore, the flow completion system comprising a tubing spool which includes a central bore that extends axially therethrough and a production outlet which communicates with the central bore; a tubing hanger which is supported in the central bore and which includes a production bore that extends axially therethrough and a production passageway that communicates between the production bore and the production outlet, the tubing hanger supporting a tubing string which extends into the well bore and defines a tubing annulus surrounding the tubing string; a first closure member which is positioned in the production bore above the production passageway; a first annular seal which is positioned between the tubing hanger and the central bore above the production passageway; wherein the first closure member and the first seal comprise a first pressure-containing barrier between the well bore and a surrounding environment; a second closure member which

Abstract: The invention is directed to a tubing hanger for a flow completion system which comprises a Christmas tree connected above a wellhead housing that includes a central bore in which the tubing hanger is supported, the tubing hanger comprising a generally annular body; a production bore which extends generally axially through the body; an annulus bore which extends generally axially through the body; the annulus bore comprising a generally lateral first branch which is connected to a generally axial second branch; and a closure member which includes a gate that is moveable generally axially across the first branch between an open position in which a hole in the gate is aligned with the first branch and a closed position in which the hole is offset from the first branch.

Abstract: A tensioning device is disclosed which brings two tubular segments closer together with an intermediate adjustment sleeve. The sleeve is threaded externally and may be accessed internally by a tool to rotate it. The threaded sleeve is secured to the upper tubular in a manner that permits relative rotation. Rotation of the sleeve advances it downwardly in the lower tubular, pulling down the upper tubular secured to the rotating sleeve. The upper tubular translates until a load shoulder hits a support surface in the wellhead to achieve the desired tension in the string.

Abstract: A method of drilling an offshore underwater well comprising the steps of installing a riser conduit (5) so that it is substantially vertically supported at a production deck (1,25). The riser conduit (5) deviates progressively further from the vertical with increasing sea depth, so that its end can be anchored at the seabed (6) by a skid (7) either at an oblique angle so that drilling into the seabed can be carried out at the oblique angle, or horizontally, so that the riser conduit can extend some considerable distance across the seabed (6) before drilling is carried out.

Abstract: A controls bridge for a flow completion system which comprises a tubing spool having a production outlet, a tubing hanger having a production bore that communicates with the production outlet and at least one service and control conduit extending therethrough, and at least one external service and control line that terminates near the tubing spool, the controls bridge comprising a first body portion; a mechanism for securing the first body portion to the top of the tubing spool and/or the tubing hanger; at least one first coupling member which is adapted to engage a second coupling member that is mounted in the service and control conduit; at least one third coupling member which is adapted to engage a fourth coupling member that is connected to the external service and control line; a bridge line which is connected between the first coupling member and the third coupling member; a first actuator for moving the first coupling member into engagement with the second coupling member; and a second actuator for mo

Abstract: In accordance with a method of servicing a well there is provided a casing spool having an endless tubing access port. The endless tubing access port has a feed passage that extends toward the first end and outwardly from the body. The feed passage terminates in a flow control valve. Endless tubing is extended through the endless tubing access port while a tubing hanger is still in position supporting a tubing string. The endless tubing passes along the central flow passage beside the tubing string. Fluids are then pumped through the endless tubing to promote circulation within the well.

Abstract: A well production assembly includes a production tree which has a lateral production passage extending laterally from a vertical bore of the tree. A tubing hanger, also having a lateral production passage, lands in the tree, with the lateral passages registering with each other. The junction of the lateral passages has flat, tapered sealed areas which mate with one another. An annulus passage extends vertically through the tubing hanger offset from and parallel to the tubing hanger vertical production passage. The annulus passage also has a lateral passage which registers with the lateral passage formed in the tree. The annulus lateral passages have a flat seal area at their junction. The tubing hanger has a downward facing hydraulic connector which registers with an upward facing hydraulic connector located on a shoulder formed in the bore. Once mated, the connectors provide hydraulic or other auxiliary fluid communication to downhole equipment.

Abstract: Apparatus is disclosed for use in drilling and completing a subsea well of the type in which a blowout preventer stack positioned on a floating rig is connected to the well by a drilling riser, and wherein the flow of well fluid between the tubing/casing annulus and the upper end of the wellhead is controlled by valves means within passageway in a relatively thick walled upper portion of the housing above a relatively thin walled portion thereof in which a casing hanger is installed.

Abstract: A well completion system having a spool tree body defining a vertical bore extending therethrough. The vertical bore defines an annular recess adjacent to the lateral production fluid outlet port in the spool tree body. A tubing hanger is connected to the spool tree body. The tubing hanger defines a vertical production bore extending therethrough and has at least a lateral production fluid flow port. The tubing hanger is positioned within the vertical bore such that the lateral production fluid flow port in the tubing hanger is in flow communication with the lateral production fluid outlet port in the spool tree body. There is a removable plug that seals the vertical production bore extending through the tubing hanger above the lateral production fluid outlet port in the spool tree body. A stopper means seals the vertical bore extending through the spool tree body above the removable plug.

Abstract: A wellhead device for the isolation of solid particles carried by production fluid includes a closed housing to be integrated with a wellhead element, a lining tightly fixed on the inner wall of the body producing the fluid upstream of the side outlet(s) provided with the valves, and a cylindrical partition arranged inside the housing around the lining, from which it is separated by a second ring-shaped space. First openings are provided in the upper portion of the partition above the lining, second openings are provided in the lower portion of the partition, and a filter is arranged inside the housing at the periphery of the partition lower portion, opposite the second openings. The filter is arranged such that all the fluid entering through the first partition openings into the volume separating this partition from the housing outer portion passes through the filter before entering the second ring-shaped volume through the partition second openings.

Abstract: A drilling head used to seal around a drill pipe while drilling is employed in a subsea location. The drilling head has an inner body located within an outer body. At least one bearing is located between the outer body and the inner body for facilitating the rotation of the inner body relative to the outer body. A seal mounted to a lower portion of the inner body seals around the outer surface of the drill pipe. While lowering the drilling head to the wellhead, a support attached to the drill pipe is inserted into a skirt which surrounds a portion of the seal. The skirt and support are releasably connected using a J-slot mechanism. An inner annulus and an outer annulus are located between the inner and outer bodies, the annuluses containing a lubricating fluid. Helical vanes are located within the inner annulus and affixed to the inner body. The vanes rotate with the inner body for circulating the fluid through the inner and outer annuluses.

Abstract: Method and apparatus are disclosed for confirming the integrity of a seal system extending between a conduit disposed within a subterranean well and a surface or top Christmas tree assembly such that the confirmation steps do not adversely thereafter effect the sealing integrity of the system when exposed to high pressure and/or temperature environments.

Abstract: A connector assembly includes first and second connector parts. The first connector part has a bearing portion and the second connector part is connectable with the first connector part. A carriage comprises an abutment which is disposed against the first connector part and the carriage is reciprocatable between a forward position for connecting the connector parts and a retracted position for disconnecting the connector parts. A bias is provided for biasing the bearing against the abutment. The bearing portion and the abutment cooperate to permit pivoting of the first connector part in response to a force in any lateral direction on the first connector part. The first connector part may include a weakened portion providing a reduced resistance to shear. The connector assembly may also form part of a wellhead assembly.

Abstract: A tubular connection, an example of which is a subsea wellhead having a primary and secondary seal areas allows the use of a backup or contingency gasket for engagement with the secondary seal area in the wellhead should a failure occur in the primary seal area. In the preferred embodiment, the primary and secondary seal areas are sufficiently separated such that the erosion damage which occurs from leakage with the original gasket adjacent the primary seal area, which can spread below the primary seal area, leaves the secondary seal area unaffected. A backup or contingency gasket can be inserted for sealable contact with the secondary sealing area for further well operations.

Abstract: A slimbore marine riser and BOP are provided for a subsea completion system which includes a tubing spool secured to a wellhead at the sea floor. The tubing spool has an internal landing profile for a reduced diameter tubing hanger which is arranged and dimensioned to pass through the bore of the riser and BOP at the end of a landing string. The tubing hanger, arranged and designed to be sealingly positioned in the tubing spool landing profile, has a production bore and a relatively large multiplicity of electric and hydraulic passages which terminate at a top end of the hanger with vertically extending electric and hydraulic couplers. A passage is provided through the body of the tubing spool which provides communication from above the tubing hanger to the well annulus below the hanger. A remotely controllable valve is placed in the annulus bypass passage.

Abstract: A Christmas tree (16) is based on a dual bore sub-sea test tree. The Christmas tree consists of a Christmas tree housing (56), which connects to a wellhead (44), a Christmas tree valve block assembly (62) disposed in the housing (56) and a tree cap (84) which connects to the housing (56) and valve block assembly (62). In a preferred embodiment the valve block assembly (62) has a main production bore (70) with two valves (72,74) in series and two auxiliary bores (76,96). One auxiliary bore (96) has a valve (98) for facilitating control of the annulus bore (96) whereas the other annulus bore (76) has no valve and provides a pathway for an electrical submersible cable (66) to a pump. The valves (72,74,98) are actuatable via control from an umbilical (94) and provide the facility to seal the production and annulus access bores to meet statutory requirements. A tubing hanger is not required.

Abstract: A swivel assembly for installation at a well for subsea production of oil or gas and adapted to be connected to a production vessel at the sea surface. The swivel assembly comprises a main fluid swivel having at least two paths and an electric/hydraulic auxiliary swivel for signal communication and power transfer. The fluid swivel is provided with a rotatable swivel housing at the top of a stationary christmas tree, preferably comprising a small number of valves, such as a production master valve and an annulus master valve. The paths are through-running vertically in the central core member of the fluid swivel so as to make possible well intervention from the upper side of the fluid swivel.

Abstract: A wellhead for use with a surface mounted pumping unit operating a rod string extend to a downhole pump in a well. The wellhead includes a body having a bore for a rod string, a support rod assembly moveable across the bore for coupling with a rod string having a coupling flange to provide a rod string hanger and a releaseable lock operable with the rod string. The wellhead also comprises a hydraulic seal in the body around the bore to seal with a rod string through the bore. Blowout preventer rams in the body for closing off around the rod string through the body and closing off the bore through the body when no rod string is present. A securing structure at the opposite ends of the body secures the wellhead with a rod string operator above the wellhead and to secure the wellhead with a casing flange on a well.