Abstract: A packoff assembly for sealing the annulus between the outside surface of a tubing hanger and the internal bore of a subsea wellhead includes a packoff sleeve insertable in the annulus and a seal assembly on its lower end. A release sleeve is disposed around the upper end of the packoff sleeve and is axially movable with respect thereto. An internal shoulder on the packoff sleeve receives a lock ring on the tubing hanger when the seal assembly is set to lock the packoff assembly to the tubing hanger. Circumferentially spaced apart dogs on the packoff sleeve and radially slidable on the shoulder are forced inwardly by the release sleeve when it is pulled up to retract the lock ring from the shoulder and release the packoff assembly from the tubing hanger. A running tool for running the tubing hanger and packoff assembly into the well and setting the packoff includes telescoping upper and lower body members.

Abstract: A well tool for running, landing and setting a casing hanger and a packoff in a wellhead housing, and pressure-testing the integrity of the packoff seal, all in a single trip into the well.

Abstract: An improved subsea hanger and seal having a hanger body with an external landing shoulder and an upstanding sealing rim with external sealing teeth and multiple internal camming surfaces and an actuating ring which fits within the sealing rim and includes external multiple camming surfaces mating with the camming surfaces on the interior of the sealing rim to move said sealing rim into initial set position and allow subsequent pressure to be applied to the interior of the actuating ring to deform the sealing rim into positive gripping and sealing engagement with the interior of the subsea wellhead housing in which the hanger is landed.

Abstract: A subsea wellhead housing for an underwater well has a small, integral landing shoulder in the bore for supporting an intermediate casing string. The small landing shoulder permits passage of a standard 171/2 inch drill bit. Breech block teeth are provided in the wellhead housing bore above the small landing shoulder for attaching a separately installable landing shoulder insert. The breech block teeth also permit passage of a standard 171/2 inch drill bit. An intermediate casing hanger is landed on the small, integral shoulder, and the landing shoulder insert installed in the wellhead housing. The landing shoulder insert has a skirt at its lower end which is received in and sealed against the upper end of the hanger. The upper end of the landing shoulder insert is sealed against the wellhead housing bore. In one embodiment, the hanger for 17 inch casing is fluted on its outer surface to pass through breech block slots in the wellhead housing bore in order to reach its landing shoulder.

Abstract: A seal assembly for providing reliable sealing between a subsea wellhead and a casing hanger suspended within the wellhead which provides a metal band between the top and the bottom of the seal section for strength, setting force acting against the portion of the seal outside of the metal band, collapsing of the metal band by pressure generated in the portion of the seal, and the movement of the metal band setting the seal within the seal onto the casing hanger.

Abstract: An improved subsea wellhead seal assembly include an annular body having a pair of lower annular skirts, one extending downwardly and outwardly and the other extending downwardly and inwardly, a lower landing ring and means movably securing the lower landing ring to the annular body so that, when the lower landing ring is landed, the annular body continues its downward movement to deform the annular skirts outwardly and inwardly into sealing engagement with the walls of the annulus. A reaction ring is provided above landing ring for engagement by the ends of skirts and spacer rings may be used to preselect the level of the sealing surface engagement by the skirts.

Abstract: The improved wellhead seal assembly includes an annular metal seal ring having upper spaced apart inner and outer rims with an upper energizing ring positioned between such rims and movable axially between them, a resilient seal embedded in and extending through ports in the central portion of the seal ring, lower inner and outer seal rings connected to said central portion of said seal ring by inner and outer bellows and a wedging ring depending from the central portion of the seal ring between such bellows and adapted to move downward between the inner and outer seal rings to wedge them apart into sealing engagement with the inner and outer sealing surfaces, such movement being responsive to downward movement of the upper energizing ring and the flexing of the lower bellows legs and continued movement of said upper energizing ring wedging said upper rims apart into sealing engagement with the inner and outer sealing surfaces, the upper energizing ring being releasably connected to the upper seal rims so tha

Abstract: An improved annular seal between tubular members in a subsea wellhead having an annular seal member with a U shape in section with the opening facing upwardly and two interengaged annular wedges for energizing the sealing surfaces of the inner and outer portions of the seal member at different levels. The interengagement of the wedges includes sufficient play to provide proper energizing of both inner and outer sealing surfaces at the same time. Further, the inner sealing surface is positioned at a much higher level than the outer sealing surface and close to the upper end of the inner member in which it is to seal to minimize the setting force for the inner sleeve and to minimize the amount of drag the seal will incur when retrieved. Also, the location of the outer sealing surface close to the inner member shoulder minimizes the reaction path of the lockdown sleeve.

Abstract: A packoff assembly for sealing the annulus between the outside surface of a tubing hanger and the internal bore of a subsea wellhead includes a packoff sleeve insertable in the annulus and a seal assembly on its lower end. A release sleeve is disposed around the upper end of the packoff sleeve and is axially movable with respect thereto. An internal shoulder on the packoff sleeve receives a lock ring on the tubing hanger when the seal assembly is set to lock the packoff assembly to the tubing hanger. Circumferentially spaced apart dogs on the packoff sleeve and radially slidable on the shoulder are forced inwardly by the release sleeve when it is pulled up to retract the lock ring from the shoulder and release the packoff assembly from the tubing hanger. A running tool for running the tubing hanger and packoff assembly into the well and setting the packoff includes telescoping upper and lower body members.

Abstract: A tubing hanger alignment system for a subsea well, periodically subjected to treatment by removing the well tubing and inserting treating tools therein, wherein a tubing guidance system cooperating with the wellhead for engaging a downwardly moving tubing hanger running system thereby to rotate said tubing hanger sufficiently to position the carried tubing at a predetermined relationship with the wellhead, thereby providing access into the tubing hanger for sealing elements of an over-positioned subsea tree co-operative with the wellhead.

Abstract: A running tool is used to set a seal on a casing hanger in a wellhead. The running tool has a holder for connecting the running tool to the casing hanger as it is lowered into the wellhead. A piston is carried on the running tool above the seal. An actuating passage extends from an axial passage in the running tool to the piston. A release passage extends from the axial passage to the holder. A pin and slot enables the upper section of the tool to be lowered relative to the lower section. The combination of a sliding valve, moved by a plug pumped from the surface, and the pin and slot, places the running tool in a mode for setting the seal and a mode for releasing the running tool from the casing hanger.

Abstract: A subsea wellhead structure including a casing hanger having an exterior downwardly facing shoulder for landing within a well bore, a central bore, means for connecting a casing thereto, an upper exterior surface tapering downwardly and outwardly, and an external surface below said shoulder tapering downwardly and inwardly for centering said hanger on landing, a seal assembly with a metal seal sleeve having downwardly extending fingers, an internal metal annular bulbous sealing surface and an external metal cylindrical sealing surface, means for latching said seal sleeve in sealing position, a protector sleeve and means for releasably securing said protector sleeve to said seal assembly and said latching means, the latching means including retaining means preventing premature setting or movement of the latching means prior to the setting of said sealing means.

Abstract: A method and apparatus comprising a mudline casing hanger tieback adaptor with an adjustable load ring for connecting an installed subsea wellhead on the mudline suspension system.The mudline casing hanger tieback adaptor (180) includes a mudline hanger adaptor body (182) with an adjustable load ring 184, a packoff nut (104) and packoff (102), casing pup (186), and a tieback tool (190), all of which are lowered on a running tool to be connected to an already installed subsea wellhead (80) and sealably connected to an already installed casing hanger (64) on the innermost casing of a mudline supsension system. The adjustability of the load ring compensates for any tolerance buildup in the already installed casing (32) and adjustably shouldering the load ring (184) on the wellhead (80) transfers the load imposed on the innermost tieback tool (190) and casing hanger (70) back to the wellhead (80) during the high pressure testing of the packoff seal (202) between the tieback tool (190) and casing hanger.

Abstract: The subsea wellhead system includes a wellhead, a housing seat disposed in and connected to the wellhead, a casing hanger supported by the seat, a holddown and sealing assembly in the annulus between wellhead and hanger, a running tool attached to the hanger for lowering it into the well and initially actuating the holddown and sealing assembly, and apparatus for applying hydraulic pressure to further actuate the seal. The housing seat and wellhead are connected by breech block teeth. The seat maintains 360.degree. bearing surface with the hanger. The holddown and seal assembly includes an upper rotating member threadingly engaging the hanger and suspending a lower stationary member. The latter includes a Z-shaped portion having a plurality of frustoconical metal rings positively connected by links. The rings form grooves housing resilient elasotmeric members.

Abstract: The subsea wellhead system includes a wellhead, a housing seat disposed in and connected to the wellhead, a casing hanger supported by the seat, a holddown and sealing assembly in the annulus between wellhead and hanger, a running tool attached to the hanger for lowering it into the well and initially actuating the holddown and sealing assembly, and apparatus for applying hydraulic pressure to further actuate the seal. The housing seat and wellhead are connected by breech block teeth. The seat maintains 360.degree. bearing surface with the hanger. The holddown and seal assembly includes an upper rotating member threadingly engaging the hanger and suspending a lower stationary member. The latter includes a Z-shaped portion having a plurality of frustoconical metal rings positively connected by links. The rings form grooves housing resilient elastomeric members.

Abstract: A torque multiplier subsea tool for setting a seal between a casing hanger and a subsea wellhead includes a mandrel having a sun gear with axial elongate teeth. An outer barrel is disposed around the mandrel forming an annulus therebetween. A planetary gear assembly is disposed in the annulus between the barrel and the sun gear to transmit to the barrel a torque which is higher in magnitude than that applied to the mandrel. A connector body disposed around the mandrel, below the planetary gear assembly, includes radially movable dogs for engaging the casing hanger. The barrel engages the sealing assembly and transmits the increased torque thereto to advance the sealing assembly downwards and to set the seal. The mandrel advances downwards with the sealing assembly and releases the dogs from the casing hanger. An emergency release mechanism is provided to advance the mandrel downwards to release the dogs in the event such downward movement is prevented during normal seal setting operation.

Abstract: A torque multiplier subsea tool for setting a seal between a casing hanger and a subsea wellhead includes a mandrel having a sun gear with axial elongate teeth. An outer barrel is disposed around the mandrel forming an annulus therebetween. A planetary gear assembly is disposed in the annulus between the barrel and the sun gear to transmit to the barrel a torque which is higher in magnitude than that applied to the mandrel. A connector body disposed around the mandrel, below the planetary gear assembly, includes radially movable dogs for engaging the casing hanger. The barrel engages the sealing assembly and transmits the increased torque thereto to advance the sealing assembly downwards and to set the seal. The mandrel advances downwards with the sealing assembly and releases the dogs from the casing hanger. An emergency release mechanism is provided to advance the mandrel downwards to release the dogs in the event such downward movement is prevented during normal seal setting operation.

Abstract: Method for completing an underwater well includes locating drilling apparatus at the well site, and installing conductor casing in the floor of the body of water with a wellhead, blowout preventer stack, and riser attached thereto at a point near the floor, with the riser extending upwardly to the drilling means. A drill string and standard 171/2 inch drill bit is then run through the wellhead and conductor casing, and a hole is drilled for suspending 16 inch casing within the wellhead and conductor casing. A hanger-support member having a casing string attached thereto is lowered into the well until it lands in the wellhead, and it is then rotated less than 360.degree. to connect it within the wellhead. The hanger-support member is then latched within the wellhead. A hole is then drilled for suspending another casing within the wellhead, and a casing hanger with casing string is run through the riser and into the wellhead, and the casing hanger is landed on the hanger-support member.

Abstract: An improved method of completing a well having production and service strings of different sizes including the steps of running the production string on a main tubing hanger while controlling the well with a variable bore blowout preventer and running the service string into the tubing hanger while controlling the well with a dual bore blowout preventer.

Abstract: A method and apparatus is disclosed for eliminating vertical motion of a downhole tool in a subsea borehole as the tool is being operated by a drill string from a floating vessel. A vertical motion elimination means is incorporated into the drill string at a point which will be adjacent a blowout preventer stack on the marine bottom when the downhole tool is positioned at a desired point in the borehole. The vertical motion elimination means is comprised of a sleeve which is rotatably mounted on the drill string at a fixed vertical position. The sleeve is adapted to be engaged by the blowout preventer stack to fix the sleeve against vertical movement with respect to the preventer. Since the sleeve, itself, is fixed against vertical movement on the drill string, that portion of the drill string which lies below the preventer (hence, the downhole tool) will also be fixed against vertical motion within the borehole.

Abstract: There is disclosed apparatus for use in suspending concentric strings of casing of an offshore well at the ocean floor, wherein at least one hanger for suspending an intermediate casing string is provided with a plurality of vertically spaced, upwardly facing seating surfaces which extend radially inwardly from its bore, and the outer side of such hanger body has a recess thereabout in which a radially expandable ring having a plurality of vertically spaced, downwardly facing landing surfaces is received. As the intermediate hanger body is lowered into the bore of an outer hanger having vertically spaced, upwardly facing seating surfaces extending radially outwardly from its bore, the ring expands radially outwardly to move its landing surfaces into supported positions on the seating surfaces of the outer hanger.

Abstract: Method and apparatus for installing multiple strings of pipe in underwater wells in which, just prior to landing of the hanger for the multiple pipe strings, the weight of the strings is carried by a support ring releasably secured to a body member through an antifriction bearing so that rotational orientation can be accomplished.

Abstract: In a remotely installed underwater well apparatus, a tubular body, typically a multiple string tubing hanger, is landed in a position oriented rotationally with respect to a reference point on the apparatus and a seal device is then energized by the same tool employed to land and orient the tubular body.

Abstract: Method and apparatus for multiple string well completions by remote operations in underwater installations, by which the tubing strings are installed independently rather than simultaneously.

Abstract: A well system and method for completing petroleum oil and gas wells having special application to extreme environmental settings such as platform, sub sea, and floating vessel operations, and frozen regions such as the Arctic. The system effectively defines a downhole wellhead including weight supporting apparatus in which the tubing hanger is supported and a pack-off with the casing for minimizing the effects of structural damage at the surface end of the well system.