Abstract: A wellhead has, instead of a conventional Christmas tree, a spool tree in which a tubing hanger is landed at a predetermined angular orientation. As the tubing string can be pulled without disturbing the tree, many advantages follow, including access to the production casing hanger for monitoring production casing annulus pressure, and the introduction of larger tools into the well hole without breaching the integrity of the well.

Abstract: A subsea production system that is adapted to be coupled to a subsea wellhead and includes a tubing hanger adapted to be positioned in the wellhead. The tubing hanger has a flow opening extending therethrough and has at least one eccentrically located opening extending through the tubing hanger. In some cases, the tubing hanger is adapted to be not precisely oriented with respect to a fixed reference point when positioned in the wellhead. The system also includes a production tree adapted to be operatively coupled to the tubing hanger, wherein the production tree is oriented relative to the tubing hanger. In other embodiments, the tubing hanger is riot oriented with respect to the wellhead or other fixed reference point.

Abstract: A holding member provides for releasably positioning a rotating control head assembly in a subsea housing. The holding member engages an internal formation in the subsea housing to resist movement of the rotating control head assembly relative to the subsea housing. The rotating control head assembly is sealed with the subsea housing when the holding member engages the internal formation. An extendible portion of the holding member assembly extrudes an elastomer between an upper portion and a lower portion of the internal housing to seal the rotating control head assembly with the subsea housing. Pressure relief mechanisms release excess pressure in the subsea housing and a pressure compensation mechanism pressurize bearings in the bearing assembly at a predetermined pressure.

Abstract: Subsea wells are drilled and completed with an offshore floating platform in a manner that allows simultaneous work on more than one well. A first well is drilled and casing. Then a tubing hanger is run through a drilling riser and landed in the wellhead housing. Then, with the same floating platform, the drilling riser is disconnected and moved to a second well. While performing operations on the second well, the operator lowers a production tree from the floating platform on a lift line, and connects it to the first wellhead housing. An ROV assisted subsea plug removal tool is used for plug removal and setting operations required through the production tree.

Abstract: A tieback connector connects a riser between a subsea wellhead housing and a floating platform. The tieback connector has a tubular body that stabs into and seals with a casing hanger. A latch member on the tieback connector engages a locking profile to secure the tieback connector to the wellhead housing. A sleeve is slidably carried on the tubular body between a running-in position and a set position. The lower end of the sleeve lands on an upper rim of the casing hanger prior to the seal engaging the seal surface. Continued downward movement of the tubular body relative to the sleeve causes the seal to engage the seal surface and the sleeve to move to the set position. The sleeve has upper end that engages a lower end of the latch member to limit any upward movement of the casing hanger in the wellhead housing.

Abstract: An inner riser adjustable hanger and seal assembly are provided for applying tension to a casing string secured at a lower end within a well and supported at an upper end by a wellhead housing. The wellhead housing has a locking member on an inner surface thereof. A tensioning mechanism tensions the casing string and secures the upper end to the wellhead housing. A seal body locking member is radially moveable into engagement with the housing locking member to fix the axial position of the seal body relative to the wellhead housing. An upper seal assembly seals between the seal body and the wellhead housing, and a lower assembly seals between the seal body and the casing string. The casing string is tensioned without appreciable rotation of the hanger body or the upper and lower seal assemblies.

Abstract: A subsea wellhead assembly has a tubing hanger with a tubing annulus passage and a production passage. A metal-sealing shuttle valve is mounted in the tubing hanger for blocking upward flow through the tubing annulus passage. The shuttle valve has a retention mechanism that prevents the shuttle from moving to the open position when fluid pressure is applied from above. The running tool releases the retention mechanism after testing has been completed, causing the shuttle to close. The tree has an engaging member that can be stroked downward into the tubing hanger annulus passage to move the shuttle valve to the open position for communicating with the annulus.

Abstract: A holding member provides for releasably positioning a rotating control head assembly in a subsea housing. The holding member engages an internal formation in the subsea housing to resist movement of the rotating control head assembly relative to the subsea housing. The rotating control head assembly is sealed with the subsea housing when the holding member engages the internal formation. An extendible portion of the holding member assembly extrudes an elastomer between an upper portion and a lower portion of the internal housing to seal the rotating control head assembly with the subsea housing. Pressure relief mechanisms release excess pressure in the subsea housing and a pressure compensation mechanism pressurize bearings in the bearing assembly at a predetermined pressure.

Abstract: A wellhead housing has a bore with a support shoulder, a ramp surface extending upward and outward from the support shoulder, and a recess extending upward from the ramp. A split, resilient load ring is carried in an initial position in the recess. A retractable and axially movable latch ring is carried in the recess above the load ring. A casing hanger has a profile that engages the latch ring as the casing hanger moves downwardly in the bore, causing the latch ring to move downward and pushing the load ring to the set position.

Abstract: A method for installing a subsea completion system comprises installing a conductor housing on the sea floor, landing a wellhead in the conductor housing, securing a BOP to the wellhead, landing a casing hanger in the wellhead through the BOP, connecting a tubing hanger to a THRT, landing the tubing hanger in the wellhead or the casing hanger through the BOP, installing a wireline plug in the tubing hanger production bore through the THRT, retrieving the THRT, retrieving the BOP, securing an ROSL to the christmas tree, landing the christmas tree on the wellhead, and retrieving the wireline plug from the tubing hanger production bore using the ROSL.

Abstract: A wellhead assembly for use on a well with a blowout preventer stack having a bore therethrough that utilizes an intervention spool sealingly secured between a horizontal tree and the blowout preventer stack to allow the use of a removable valve package positioned in the intervention spool with valve actuators mounted on the exterior of the intervention spool is disclosed.

Abstract: A wellhead has, instead of a conventional Christmas tree, a spool tree (34) in which a tubing hanger (54) is landed at a predetermined angular orientation As the tubing string can be pulled without disturbing the tree, many advantages follow, including access to the production casing hanger (21) for monitoring production casing annulus pressure, and the introduction of larger tools into the well hole without breaching the integrity of the well.

Abstract: A subsea well assembly includes a wellhead housing 50 having a cylindrical inner sealing surface and a tubular hanger 10 having a tapered external sealing surface. The running tool 30 includes a central stem 40 connected to the running string. A setting piston 72 is responsive to fluid pressure in the annulus about the running string, and has a radially outer surface and a radially inner surface each for sealing with the running tool body. Fluid pressure to set the seal assembly may be applied to the setting piston through an annulus about the running string, and may also act directly on an initially set seal assembly 20.

Abstract: A wellhead has, instead of a conventional Christmas tree, a spool tree in which a tubing hanger is landed at a predetermined angular orientation. As the tubing string can be pulled without disturbing the tree, many advantages follow, including access to the production casing hanger for monitoring production casing annulus pressure, and the introduction of larger tools into the well hole without breaching the integrity of the well.

Abstract: A subsea wellhead assembly has the capabilities of communicating from a tree assembly mounted on an inner wellhead housing to a casing annulus. A passage in the wellhead assembly extends within the bore of the wellhead housing from the casing annulus to the tree assembly. A portion of the passage is located within a casing hanger. The passage is opened and closed by a valve. The valve does not open the passage until the tree assembly is connected to the wellhead housing and a tubing hanger orientation sleeve lands in the wellhead assembly. The tubing hanger orientation sleeve actuates the valve when it lands to open the passage. When the passage is opened, the casing annulus is in fluid communication with the interior surface of the wellhead housing, which is in communication with the tree assembly.

Abstract: The annulus pressure is controlled by displacing incompressible fluid with compressible fluid in the annulus. The displaced fluid is filtered to avoid clogging small lines. The presence of compressible fluid minimizes the thermal effect of warm fluid in the production tubing on annulus pressure. As a result, thinner wall casing can be used, for considerable savings in material and installation cost.

Abstract: In a subsea wellhead assembly, a collet ring assembly is used with a hanger for suspending a string of conduit in a subsea wellhead assembly. The ring assembly includes a collet that extends around an outer surface of the hanger. The collet has an upper portion that rotates radially between locked and unlocked positions. The ring assembly has a protruding lower portion extending radially outward from the hanger for engaging an interior surface of the wellhead assembly, which causes the upper portion of the collet to rotate radially outward to engage the interior surface of the wellhead assembly in a locked position. The ring assembly includes a back-up ring that engages the interior of the collet, which the collet rotates around between its locked and unlocked positions.

Abstract: A running tool 10, a lockdown sleeve 27, and a seal ring 24 are provided for axially fixing upward movement of a tubular hanger with respect to a subsea wellhead. The running tool 10 includes a tool latching and unlatching mechanism 51 for axially connecting the running tool to the subsea wellhead housing, a tool force applicator 64 for exerting a downward setting force, and a sleeve latching mechanism 73 for securing the lockdown sleeve to the subsea wellhead housing 20. The seal 24 is provided between the lockdown sleeve and one of the tubular hanger and the wellhead housing. The method of the invention includes running the tool and sleeve in open water to the subsea wellhead housing, locking the tool to the housing, setting the seal, locking the sleeve to the housing, then retrieving the tool in open water.

Abstract: A pre-tensioning arrangement for inner and outer elongate concentric members includes a load member which is axially movable in an actuating direction relative to the inner member and has an outer surface which tapers in the actuating direction, a laterally expansible ring which is engaged by the load member in an inclined engagement zone during the actuating movement, and an engagement zone between the laterally expansible ring and the outer member, the engagement zones providing a mechanical advantage between the movement of the load member and movement of the outer member.

Abstract: A large bore Christmas tree includes a production outlet that is split into multiple separate outlets, each controlled by a separate, standard sized valve and valve actuator.

Abstract: A wellhead has, instead of a conventional Christmas tree, a spool tree in which a tubing hanger is landed at a predetermined angular orientation. As the tubing string can be pulled without disturbing the tree, many advantages follow, including access to the production casing hanger for monitoring production casing annulus pressure, and the introduction of larger tools into the well hole without breaching the integrity of the well.

Abstract: A horizontal spool tree wellhead system 10 utilizes a casing 18, 19 installed in a well bore and a wellhead housing 20 at the upper end of the casing. A spool 23 of the horizontal tree 22 is connected to the upper end of the wellhead housing, and includes at least one radially extending side port. The BOP 28 is also installed at the upper end of the housing with a bore aligned with the wellhead housing bore. After drilling the well, the casing string 19 carrying a casing hanger 42 may be lowered through the bores of the BOP, the spool tree, and the wellhead housing and into the well. An orientation/isolation sleeve 60 may be installed in a predetermined rotational orientation with the spool tree. A tubing hanger 70 having a side port is landed onto the orientation sleeve and is automatically oriented to align the tubing hanger side port with the spool side port.

Abstract: A subsea wellhead assembly has a tree that connects internally to the bore of wellhead housing. The tree has a lower end that has a lock member that is moved radially outward into engagement with a profile in the bore of the wellhead housing. The tree is a monobore, having a production passage but no tubing annulus passage extending through it. The tubing hanger has a tubing annulus passage and a production passage. A valve is mounted in the tubing hanger for controlling flow through the tubing annulus passage.

Abstract: In a subsea wellhead assembly, a connector attaches a production riser or subsea tree to a wellhead housing. The connector includes a piston that cams a plurality of dogs into and out of engagement with the wellhead housing while sliding axially upward and downward relative to the wellhead housing. The piston is typically actuated by injecting hydraulic fluid into either an upper chamber or lower chamber to move the piston axially up or down. While in the axially downward, or locked position, the piston houses an override chamber. Hydraulic fluid is injected into the override chamber to move the piston axially upward and unlock the connector when the seals of the lower chamber fail.

Abstract: A subsea wellhead assembly allows communication between a production tubing annulus and a conduit in fluid communication with a platform above. The wellhead assembly has a tubing hanger that is held relative to a tubular wellhead member of a subsea well by a tubing hanger support. A string of tubing extends from the tubing hanger into the well, defining an annulus around the tubing. The conduit communicates with the tubing annulus through a tubing annulus passage. The tubing annulus passage has a portion extending through the tubing hanger support. The wellhead member supports a valve block located between the tubing hanger support and the riser. The tubing annulus passage has another portion that registers with the portion of the passage in the tubing hanger support. The conduit stabs into valve block portion of the tubing annulus passage when the riser connects to the upper end of the valve block.

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 subsea wellhead assembly has a tubing hanger with a tubing annulus passage and a production passage. A metal-sealing shuttle valve is mounted in the tubing hanger for blocking upward flow through the tubing annulus passage. The shuttle valve has a retention mechanism that prevents the shuttle from moving to the open position when fluid pressure is applied from above. The retention mechanism is released by the running tool after testing has been completed, causing the shuttle to close. The tree has an engaging member that can be stroked downward into the tubing hanger annulus passage to move the shuttle valve to the open position for communicating with the annulus.

Abstract: A horizontal spool tree wellhead system 10 utilizes a casing 18, 19 installed in a well bore and a wellhead housing 20 at the upper end of the casing. A spool 23 of the horizontal tree 22 is connected to the upper end of the wellhead housing, and includes at least one radially extending side port. The BOP 28 is also installed at the upper end of the housing with a bore aligned with the wellhead housing bore. After drilling the well, the casing string 19 carrying a casing hanger 42 may be lowered through the bores of the BOP, the spool tree, and the wellhead housing and into the well. An orientation/isolation sleeve 60 may be installed in a predetermined rotational orientation with the spool tree. A tubing hanger 70 having a side port is landed onto the orientation sleeve and is automatically oriented to align the tubing hanger side port with the spool side port.

Abstract: A running tool 10, a lockdown sleeve 27, and a seal ring 24 are provided for axially fixing upward movement of a tubular hanger with respect to a subsea wellhead. The running tool 10 includes a tool latching and unlatching mechanism 51 for axially connecting the running tool to the subsea wellhead housing, a tool force applicator 64 for exerting a downward setting force, and a sleeve latching mechanism 73 for securing the lockdown sleeve to the subsea wellhead housing 20. The seal 24 is provided between the lockdown sleeve and one of the tubular hanger and the wellhead housing. The method of the invention includes running the tool and sleeve in open water to the subsea wellhead housing, locking the tool to the housing, setting the seal, locking the sleeve to the housing, then retrieving the tool in open water.

Abstract: A horizontal spool tree wellhead system 10 utilizes a casing 18, 19 installed in a well bore and a wellhead housing 20 at the upper end of the casing. A spool 23 of the horizontal tree 22 is connected to the upper end of the wellhead housing, and includes at least one radially extending side port. The BOP 28 is also installed at the upper end of the housing with a bore aligned with the wellhead housing bore. After drilling the well, the casing string 19 carrying a casing hanger 42 may be lowered through the bores of the BOP, the spool tree, and the wellhead housing and into the well. An orientation/isolation sleeve 60 may be installed in a predetermined rotational orientation with the spool tree. A tubing hanger 70 having a side port is landed onto the orientation sleeve and is automatically oriented to align the tubing hanger side port with the spool side port.

Abstract: In a subsea wellhead assembly, a tubing hanger in communication with the subsea well has a hanger port extending through its side. A diverter surrounds the tubing hanger and diverts well fluid transmitted from the hanger port around a portion of the tubing hanger. The diverter transmits the well fluid to the inner surface of a wellhead member. A production port extending through a side of the wellhead member transmits the well fluid from the tubing hanger and diverter to an exterior of the wellhead member.

Abstract: An outer wellhead housing has an external locator member initially oriented in a desired direction. An inner wellhead housing lands in the outer wellhead housing. A BOP orientation spool with an external orientation member and an internal orientation member lands on the inner wellhead housing and orients via the external locator member. A tubing hanger with an orientation member and associated tubing hanger running tool with another orientation member lower through the BOP orientation spool and orient as they land in the inner wellhead housing. A production tree with an orientation member on a lower end lands on the inner wellhead housing. The orientation member of the production tree engages the orientation member of the tubing hanger to rotate the tree to a desired orientation.

Abstract: A horizontal spool tree assembly 10 is provided for supporting a production tubing string 22 within a well below a BOP. The spool body 12 includes a laterally extending passageway 36 which is in fluid communication with a similar laterally extending passageway 34 provided in a tubing hanger 20. The tubing hanger includes a central bore for fluid communication with the production tubing string, and a workover flow path 30 extending axially through the tubing hanger, with a workover valve 32 provided for controlling the fluid flow in the workover passageway. An annulus port 70 extends laterally through the spool body, and an annulus valve 72 controls fluid flow through the annulus port.

Abstract: A method for installing a subsea completion system comprises installing a conductor housing on the sea floor, landing a wellhead in the conductor housing, securing a BOP to the wellhead, landing a casing hanger in the wellhead through the BOP, connecting a tubing hanger to a THRT, landing the tubing hanger in the wellhead or the casing hanger through the BOP, installing a wireline plug in the tubing hanger production bore through the THRT, retrieving the THRT, retrieving the BOP, securing an ROSL to the christmas tree, landing the christmas tree on the wellhead, and retrieving the wireline plug from the tubing hanger production bore using the ROSL.

Abstract: Methods and devices are described for efficiently installing sea-borne wellhead components and tying back sub-sea wellhead components with them. In specific aspects, a single running and setting tool is used to land a tubing head housing upon the stem of a floating platform and tension and pressure testing casing string risers extending between a subsea wellhead and a floating vessel.

Abstract: A tubing spool has an internal landing profile for a reduced diameter tubing hanger which is arranged and dimensioned to pass through the bore of a slimbore marine riser and BOP of a subsea completion system. The tubing spool is arranged and designed for securement to a wellhead at the sea floor. The tubing hanger is arranged and designed to be sealingly positioned in the tubing spool landing profile and has a production bore and a relatively large multiplicity of electrical and hydraulic passages which terminate at a top end of the hanger with vertically extending electrical and hydraulic couplers. A passage is provided, independent of the tubing hanger, which provides communication from above the tubing hanger to the well annulus below the hanger. The tubing spool may have a slim bore BOP or a conventional xmas tree attached at its top end.

Abstract: An apparatus and technique for use in spacing out tubular strings within a well includes a casing that has an inner wall and at least one profile that is disposed within the inner wall. A tubing hanger is attached to the well tubing and if capable of landing within a target location, such as a wellhead. When the landing tool is seated within the profile, the length of well tubing needed to land the tubing hanger within the target location can be determined. A landing tool is linked to well tubing and is sized so as to seat within the profile.

Abstract: An apparatus for use in a subsea well including a bore, wherein the apparatus has a tubing hanger body having an annulus therethrough, a ball valve in the annulus adapted for opening and closing the annulus, comprising a ball valve body within a valve chamber in the tubing hanger body which forms a continuation of the tubing hanger passageway at one end and is closed at its opposite end; a tubular valve housing for the ball valve; the ball valve body having a ball valve closure member substantially in the form of a spherical ball defining two annular valve seats concentric with the annulus for the ball valve; the spherical ball being longitudinally movable and rotatable extending transversely in alternating positions between spherical upstream and downstream valve seat preventing flow through the passage; and a remote source for hydraulically moving the spherical ball.

Abstract: There is disclosed subsea well apparatus in which a wellhead member body is adapted to be lowered into and latched within the bore of a conductor by means of split locking and ratchet rings carried by the body in response to the weight of the casing suspended from the body. The locking ring has locking teeth engageable with locking grooves in the bore, and the ratchet ring has ratchet teeth engageable with ratchet grooves within the locking ring. Upper and lower coaxial downwardly and inwardly extending wedge surfaces are tightly engaged as the body is latched within the conductor.

Abstract: A completion system for a subsea well includes a tree having a generally cylindrical wall forming an internal bore therethrough and a production port extending laterally through the wall in communication with the internal bore. The internal wall has a landing arranged to support a tubing hanger having seals for sealing the production port between the tubing hanger and the internal wall, the production port being arranged to communicate with a lateral production fluid outlet port in the tubing hanger. A workover port extends laterally from an opening in the internal wall below the production port and the production port seals and a tubing annulus seal sealing the workover port from the tubing annulus. A tubing annulus port extends from an opening in the tree below the tubing annulus seal and the tubing annulus port and workover port being arranged to be in fluid communication externally of the internal bore.

Abstract: A flow completion system for controlling the flow of fluid from a well bore, the flow completion system comprising a tubing spool, a 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 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 is positioned in the production bore above the first closure member; and a second annular seal wherein the second closure member and the second seal comprise a second pressure-containing barrier between the well bore and the environment; and wherein both the first and the second barriers are associated with the tubing hanger.

Abstract: A method for drilling and completing oil wells of small intermediate diameter, in particular for application in ultra deep water. The method includes two drilling and running stages. The first stage of drilling and running provides for drilling the well and running at least first and second casings. The second stage provides for drilling and running at least two and more preferably three suspended liners.

Abstract: A tubing hanger including a tubing hanger body having a tubing string which is adapted to be supported in the bore of the wellhead housing wherein the apparatus comprises a flapper valve disposed in or below the tubing hanger, wherein the valve further comprises a flapper valve having a flapper valve closure member substantially in the form of a concave spherical segment defining an annular valve seat concentric with the tubing for the flapper valve; a flapper plate disposed in the valve chamber for rotatable movement from a valve position in which the flapper plate is removed from the annular valve seat to a valve position in which the flapper plate extends transversely across the flow passage for the flapper valve and forms a sealing engagement with the annular valve seat and the sealing surface is substantially in the form of a convex spherical segment, wherein the convex spherical segment is disposed intermediate between the first and second planar surfaces.

Abstract: A gate valve for a component which includes an elongated body and a flow passage extending generally longitudinally through the body, the flow passage including a generally lateral first branch connected to a generally longitudinal second branch. The gate valve comprises a gate which is moveable generally longitudinally 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; a conduit which extends through the body from the gate; an actuating mechanism positioned in the conduit for moving the gate from a first position to a second position; and a return biasing mechanism for moving the gate from the second position to the first position; wherein one of the first and second positions corresponds to the open position of the gate and the other position corresponds to the closed position of the gate; and wherein the conduit extends generally longitudinally through the body.

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: A wellhead load ring constructed in the shape of a C-ring is pre-installed in a wellhead in a storage position that maintains full bore of the wellhead. The load ring is secured in this position by shear pins. The shear pins are sheared by a tool that pushes the load ring into an operational position where it rests on a landing shoulder of a support ring. The load ring is further secured in this position by one of several latching methods.

Abstract: A wellhead apparatus which includes a spool for use in a horizontal tree and having a vertical bore therethrough, and a tubing hanger adapted to be lowered into and landed within the bore of the spool to suspend a tubing string on the lower end of the tubing hanger within the wellbore. The spool has a radial opening therethrough to receive a bellows which forms a fluid passageway removably mounted within the opening by means of a flange on the outer end of the bellows releasably connected to the outer side of the spool. The tubing hanger has an opening therethrough which includes a lateral portion connecting with its outer diameter and a vertical portion leading to a pressure responsive operator for a tubing safety valve. The passageways have seal surfaces on their opposing ends, and the end of the stem is engaged by the seal surface of the bellows to open the poppet as the hanger is lowered.

Abstract: A mid-water tethered buoyant support assembly for a riser system for use in water is described to bring fluids from seabed equipment to a production vessel at the surface. The tethered buoyant support assembly comprises at least two tethers (6) from seabed anchors, at least one beam assembly (2) extending between and connected to the tops of the tethers, buoyancy means (7) to maintain tension in the tethers, and hangers (10) for lower riser portions mounted at spaced positions along the beam assembly, each hanger (10) being positioned so that the line of action of the tension due to the weight of the suspended lower riser portion is close to or on a line extending between the connections of the beam to the tethers (6) to minimize or eliminate turning moment to the beam assembly (2) tending to cause rotation of the beam around its major axis as a result of the weight of the suspended lower riser portion. The assembly is particularly designed for use in deep water.

Abstract: A landing adapter is used to softly land a tubing hanger in the bore of a production tree. The landing adapter makes initial contact so that the tubing hanger does not have to absorb the harsh impact. The landing adapter has a hydraulic sleeve that strokes axially relative to the tubing hanger. Initially, the sleeve is extended and locked when it is run into the well so that the landing adapter can be hard-landed in the bore. When the sleeve lands in the bore, the impact is absorbed by a landing adapter buffer, not by the tubing hanger. After the hanger with the landing adapter has landed in the bore, hydraulic fluid is bled off so that the tubing hanger gradually descends axially relative to the sleeve and the tree to the retracted position. The landing adapter buffer remains in the tree after the tubing hanger is landed in the bore.

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.