Abstract: The improved wellhead system includes a wellhead housing with an internal annular shoulder having a plurality of removed arcs to form an interrupted support shoulder. A casing hanger is provided with an external annular shoulder having a plurality of removed arcs which correspond with those on the wellhead housing. In a first orientation, the removed arcs of the casing hanger shoulder align with the arcs of the support shoulder in the wellhead housing to allow the casing hanger to pass through the wellhead housing or the wellhead housing to be lowered below the casing hanger. In a second orientation the remaining shoulder arcs of the casing hanger align with the support shoulder arcs to support the casing hanger. The casing hanger also includes a thread for attaching a tool whereby the casing hanger and casing attached thereto can be tensioned. An alternate embodiment of the improved wellhead system includes a wellhead housing with an internal support groove.

Abstract: A tubing hanger assembly having a metal-to-metal seal assembly for sealing the annulus between the tubing hanger assembly and an outer casing hanger assembly. The metal-to-metal seal assembly includes a static metal-to-metal seal for sealing with the tubing hanger assembly and a dynamic metal-to-metal seal for sealing with the casing hanger assembly. The static metal-to-metal seal sealingly engages the body of the tubing hanger assembly as a part of the factory assembly procedure. Thus, the static metal-to-metal seal may be tested at the factory and replaced if leakage is detected. The dynamic metal-to-metal seal has a non-sealing position when run into the well and a sealing position upon actuation downhole. The metal-to-metal seal assembly includes actuation means engageable with the outer casing assembly that actuates the dynamic metal-to-metal seal from the non-sealing position to the sealing position.

Abstract: An improved clamp and clamp supporting apparatus includes a clamp of semicircular arcuate segments with enlarged ear portions having bolt studs positioned thereon in a staggered pattern. Through holes are drilled in the ear portions in a complementary pattern to receive the bolt studs of adjacent clamp segments with nuts threaded thereon to secure the clamps around abutting clamp hubs and maintain the hubs in sealed relationship. One of the clamp hubs has paired guide rods extending therefrom on opposite sides engaging mating holes in the clamp to allow positioning the clamp in a desired position without requiring additional support means.

Abstract: A break-away flowline fitting for protecting a subsea Christmas tree to which the flowlines are connected when the flowlines are subjected to an externally applied axial load and/or bending moment. The fitting comprises a tubular member having a reduced wall thickness section integrally formed in the member and designed to part or separate axially at an externally applied load less than what would be necessary to harm the tree. A clamp closely surrounds the reduced wall thickness section and limits the pressure induced hoop membrane stress in the reduced wall thickness section to about the same value as in the adjacent normally configured fitting portions, thereby maintaining the pressure integrity of the fitting. A frame having supports disposed on the normally configured fitting portions and axially beyond each end of the reduced wall thickness section has removable reinforcing members which span the reduced wall thickness section prior to placing the fitting in service.

Abstract: A double walled riser extends from a platform to a subsea well and is connected, through a suitable connector, to the top of the wellhead housing. The wellhead housing has annulus access passageways therein. The connector has passageways therethrough which communicate at one end with the annulus access passageways in the wellhead housing and at the other end with small diameter annulus access tubes carried between the two walls of the double walled riser. The inner wall of the double walled riser comprises a pressure containing member, and the outer wall comprises a structural support member. The small diameter annulus access tubes disposed in the annulus between the inner and outer walls of the riser communicate at one end with one of the respective passageways through the connector, and extend at the other end to the platform.

Abstract: A hydraulic casing hanger and packoff installation tool includes a central tubular member with a drill pipe upper connection and an annular chamber at the lower end thereof with a pair of concentric axially movable pistons mounted therein. A plurality of fluid passages are positioned in the wall of the tubular member and extend from the piston annular chamber to the middle portion of the tubular member where it exits. The pistons have a lower tubular extension which carries releasable latching mechanism which connects the tool to the packoff to be installed and transmits the axial force of the pistons to the packoff. A drill pipe stinger extends through the annular chamber with a releasable latch mechanism mounted on an enlarged lower portion. The releasable latching mechanism connects the tool to the casing hanger for lowering the casing and hanger into the well bore.

Abstract: A method and apparatus for the protection of downhole equipment from excessive pressure conditions which includes providing structures of volume compensating material which are designed to resist normal pressures expected in the well bore. One form of the invention has a plurality of half sections of volume compensating material positioned around one of the tubular member in the annulus which has fluids that can increase in pressure to a point approaching damage to the interior of exterior member of the annulus. In another application a resilient seal includes a recess into which a ring of volume compensating material is placed to allow a place for fluids to flow when they are subjected to overpressure conditions.

Abstract: The improved annular seal of the present invention provides a seal across an annular space between facing cylindrical surfaces and includes an outer annular ring, inner annular ring, the gap between the outer annular ring and the inner annular ring being suitably sealed at one end thereof so that the open end is open to admit pressure which is to be sealed between the two rings, an outer sealing element on the exterior of said outer annular ring, and an inner sealing element on the interior of the inner annular ring so that pressure exerted between the annular rings urges them apart and their sealing elements against the surfaces of the annular space. In another form of the invention three annular rings are provided with one end of the inner and outer rings being sealing to the end of the intermediate ring and with sealing elements on the exterior of the outer ring and on the interior of the inner ring so that the sealing elements are urged into sealing engagement with the surfaces of the annular space.

Abstract: An improved wellhead casing hanger for suspension of successive casing strings with particularly small annular spacings having an adapter sleeve of double wall construction which is utilized with a load bearing shoulder on the inside of the inner member for receiving a conventional expanding type hanger, with the annulus between the inner and outer walls providing an improved fluid return path without restricting the bore of the sleeve, packoff for sealing the annulus at the appropriate time and an installation tool.

Abstract: An improved subsea wellhead including a wellhead housing landed at a subsea well location and having a plurality of hangers landed therein, each of the hangers having a seal assembly to define an annulus in the area between the exterior of the hanger and the interior of the wellhead housing below the seal provided by the seal assembly and a passage in said wellhead housing communicating with each of the annuli, the passages extending through the wellhead housing and communicating with the space above the upper surface of the wellhead housing, a spool connected to the upper end of the wellhead housing, inner and outer seals between the upper end of the wellhead housing and the spool to define the space into which the passages communicate, a passage extending upward through the spool to communicate the pressure changes in the space between the spool and wellhead housing to the surface, and check valves in each of the passages allowing flow upwardly therethrough and preventing flow downwardly therethrough to iso

Abstract: An improved well structure such as a well housing on which a casing hanger is to be landed which housing includes a high strength landing shoulder insert which allows the housing to support the casing hanger, its casing and the heavy loads associated therewith and with substantial pressure loads experienced in new wells. In one form of the invention an insert is provided in an internal recess in the housing and held therein by a housing ring threaded on the interior of the housing body. In another form an insert is introduced into an internal housing recess in the form of seat segments and bypass segments which are secured in place by the radial forming of a high strength seat ring. In still another form of the invention the high strength seat insert is segmented, positioned as segments in the internal housing recess and secured therein by the radial forming of a metal ring outwardly into internal recesses in each of the high strength seat insert segments.

Abstract: A packoff assembly for sealing an annulus between an inner tubular member and an outer tubular member including a sealing means rotatably connected to a packing nut. The sealing means includes an upper actuation ring rotatably retained on the packing nut. A sealing member having a ring-like metal body is rotatably mounted on the upper actuation ring with a roller ball connection which permits limited relative axial movement between the upper actuation ring and the sealing member. A lower actuation ring is rotatably mounted on the body of the sealing member by another roller ball connection which permits limited relative axial movement between the lower actuation ring and the body of the sealing member. The metal body of the sealing member includes a pair of frustoconical-shaped outer seal lips and a pair of frustoconical-shaped inner seal lips. An elastomeric seal ring is disposed on the body of the sealing member between each pair of metal seal lips.

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: Apparatus for connecting portions of subsea flow conduits includes a stab member with a body and having a bore therethrough, one end of which exits from the stab body through a side port. A stab receptacle includes a bore for receiving the stab body, and a flow bore intersecting the receiving bore and leading to the exterior of the receptacle. The side port communciates with the receptacle flow bore when the stab member is landed in the receiving bore. Seals above and below the side port seal the receiving bore above and below the intersection of the receptacle flow bore and receiving bore. The cross-sectional areas of the seals exposed to internal fluid pressure are substantially equal, resulting in zero blow-apart force on the stab connection. Alternatively, the lower seal can have a larger exposed cross-sectional area than the upper seal, resulting in a net force tending to hold the connection teogether.

Abstract: A packer unit and packer insert adapted for use in an annular blowout preventer. The packer insert includes a generally longitudinal web with its leading edge facing the axial bore of the packing unit sloping from top to bottom in a generally radially outward direction.

Abstract: A test tool adapted for use during pressure testing of a subsea blowout preventer stack is disclosed. The tool has an upper and a lower body connected in a first connection by left hand threads. A check valve landed in the bore of the tool prevents downward fluid flow from the interior of the tool, but allows upward flow through the tool and the attached drill pipe for the detection of leakage of the wellhead sealing tool about the wellhead during pressure testing of a blowout preventer in the stack. During testing of a shear ram blowout preventer, the upper body is disconnected from the lower body by turning the drill pipe to the right. Raising the drill pipe then causes the upper body to shift a second set of right hand threads into position and moves the upper body and the drill pipe from the bore of the shear ram allowing it to be closed for pressure testing.

Abstract: A safety valve is disclosed which may be installed on an offshore wellhead above the tubing head and below the Christmas tree. The valve has a housing with upper and lower vertical passages and a lateral housing passage. A cylindrical gate is disposed within the lateral passage and includes a "T" shaped passage therein. The gate may be moved laterally and angularly within the lateral passage. During completion or workover of the well, the gate is moved laterally until the upper and lower vertical passages are in full open communication to run drills, hangers or other large diameter devices into the well via a BOP which may be attached to the top of the housing. During normal production, the gate may be laterally moved into the intersection of the vertical and lateral passages and the small through head part of the "T" passage serves to provide a vertical flow path through the production bore which is sealed off from the larger upper and lower vertical passages.

Abstract: A coupling for first and second pipe sections where end portions on the first and second pipe sections are shaped and dimensioned so that the end portion of the first pipe section can be inserted in the end portion of the second pipe section. Penetration of the first section is limited relative to the second section. The outer surface of the end of the second pipe section adjacent to the other section includes at least a first set of continuous helical spin-up threads. A female union box is connected to the first section, the inner surface of the box including at least a first set of continuous helical spin-up threads interengaged with the set of threads on the second pipe section, the union box further including an additional set of helical power threads. A power ring is located around the first section and includes a set of helical power threads interengaged with the helical power threads on the union box.

Abstract: A connector for releasably securing end pin and box portions of adjacent pipe sections in a telescopic relationship along aligned longitudinal axis to provide an internal fluid flow passageway. One of the end portions is provided with a plurality of threaded openings disposed in a radial relationship about the longitudinal axis and adjacent the other end portion, the other end portion having a similar plurality of openings that align with the threaded openings when the end portions are positioned for connection, each of said thread openings having a threaded latch screw operably positioned therein for movement to extend from said threaded opening into the aligned opening on the other end portion for securing the end portion together.

Abstract: A method and apparatus is disclosed for controlling a well drilled from a floating drilling vessel during the time that the marine riser is removed and conductor casing is being lowered and cemented into the well. An annular blowout preventer having a bore substantially equal to that of the structural casing is provided in a stack above the structural casing wellhead. A kill line is provided to the drilling vessel and is connected to the wellbore conduit below the blowout preventer. A spool is attached to the top of the blowout preventer. A casing stripper is attached to the top of the spool and has a mandrel extending from its top about which a wellhead connector attached to the marine riser system is connected. The marine riser system includes a flow diverter at its top disposed on the drilling vessel.The hole to be lined with conductor casing is drilled through the marine riser to a depth of about one thousand (1000) feet below the sea bed.