Abstract: A subsea wellhead assembly for a subsea well including a low pressure wellhead housing having a string of conductor piping extending therefrom. A high pressure wellhead housing, having a string of outer casing suspended therefrom, lands within the low pressure wellhead housing. The high pressure wellhead housing has a housing bore. An adapter is positioned within the housing bore. The adapter has an external load shoulder that lands on a housing load shoulder of the high pressure wellhead housing. The adapter also has an adapter bore with an inner adapter load shoulder formed thereon. A casing hanger is carried in the adapter bore, and has a string of inner casing suspended therefrom and is cemented in the well. The casing hanger lands on the inner adapter load shoulder.

Abstract: A method of unloading a well using a modular adapter having a pump, a pump suction line, and a pump discharge line. The adapter is connected to a subsea wellhead assembly so that the pump suction line communicates with a main bore in the wellhead assembly and the pump discharge line communicates with a production line attached to the wellhead assembly. The production line is isolated from the main bore and the pump draws fluid from within the well and discharges it into the production line. After unloading the well, the adapter can be removed and moved to another location for well unloading.

Abstract: An improved subsea manifold system that is capable of being used in an early production system for producing hydrocarbons from a plurality of wells from a common riser system. The subsea manifold is able to control the fluid from a multiple of subsea wet-tree wells while at the same time giving the operator the option to isolate production from a single subsea well for production evaluation. The subsea manifold also includes a pigging loop which enables efficient pigging of the flowline(s) of the early production system.

Abstract: A subsea insulation device is described. The device includes a frame coupled to and at least partially enclosing a subsea component. A bag may be at least partially enclosed in the frame. The bag may substantially seal against at least one surface of the subsea component when the bag is at least partially inflated. A port may be attached to the bag. The port may allow the bag to be coupled to a fluid provider connector so that fluid can be provided into the bag to inflate the bag.

Abstract: Methods and apparatus for diverting fluids either into or from a well are described. Some embodiments include a diverter conduit that is located in a bore of a tree. The invention relates especially but not exclusively to a diverter assembly connected to a wing branch of a tree. Some embodiments allow diversion of fluids out of a tree to a subsea processing apparatus followed by the return of at least some of these fluids to the tree for recovery. Alternative embodiments provide only one flowpath and do not include the return of any fluids to the tree. Some embodiments can be retrofitted to existing trees, which can allow the performance of a new function without having to replacing the tree. Multiple diverter assembly embodiments are also described.

Abstract: An annular seal assembly for forming a seal between two annular surfaces. The seal assembly includes an annular base including a sealing surface. The seal assembly also includes a pair of spaced apart rims extending from the annular base opposite the base sealing surface and in opposite directions, the rims also including sealing surfaces. The base is elastically deformable and the rims are elastically deformable relative to the base to effect a self-energized seal between the two annular surfaces.

Abstract: A horizontal tree has a lateral passage extending from its bore. A tubing hanger having a lateral passage lands in the bore of the tree. The tubing hanger has an orientation guide mounted to it. A retractable pin is mounted in the sidewall of the tree. The orientation guide on the tubing hanger engages the pin to rotate the tubing hanger as it is being landed.

Abstract: A locking device for locking an exchangeable unit in an insertion opening of an associated housing, particular in maritime mineral oil or mineral gas extraction, comprises locking elements adjustable between an insertion opening and a locking position, wherein in its insertion direction the unit can be inserted into the insertion opening, and is locked in the locking position within the insertion opening and relative to the housing. The locking elements are formed as thread segments spaced apart by insertion gaps in the circumferential direction and arranged on the outer side of the unit and being aligned with the insertion opening, said thread segments being arranged in the insertion opening at a gap and being in thread engagement in the locking position.

Abstract: A wellhead seal assembly forms a metal-to-metal seal between inner and outer wellhead members. A metal seal ring has inner and outer walls separated by a slot. An energizing ring has a C-ring captured on its outer surface. When the energizing ring is moved further into the slot, the C-ring is forced from its pocket and engages a profile on the seal ring, locking the energizing ring to the seal assembly.

Abstract: An assembly for landing a tubing hanger in a subsea well includes a riser extending from a subsea wellhead assembly to a vessel at the surface of the sea. A tubing hanger having a string of tubing suspended therefrom is lowered through the riser with a string of conduit, and the tubing hanger lands within the subsea wellhead assembly. A sensor is positioned adjacent the subsea wellhead assembly to monitor the axial position of the tubing hanger within the subsea wellhead assembly. The sensor also communicates the axial position of the tubing hanger to the surface. A locking mechanism is carried by the tubing hanger and is selectively operable to lock the tubing hanger in place relative to the subsea wellhead assembly when the tubing hanger reaches a predetermined axial location.

Abstract: A DC voltage converting device is on the output side connected to a DC voltage source and, on the output side, supplies a converted DC voltage to at least one electrical consumer via a cable connection. To improve such a DC voltage converting device in that also with high DC voltages on the input side, a conversion into another DC voltage is possible without any special constructional efforts and high costs while complicated cooling means or the like, are avoided at the same time, the Dc voltage converting device comprises a plurality of DC voltage converting units of which each is serially connected to the DC voltage source on the input side and connected in parallel with the cable connection on the output side for supplying the converted DC voltage.

Abstract: During the completion of a subsea horizontal tree, a tubing hanger and internal tree cap are run together with the same running tool and running string. The running tool has a linking assembly that connects the tree cap to the tubing hanger during running, retrieval, or workover, so that the tree cap supports the weight of the tubing hanger and string of tubing. The linking assembly can be retrieved with the running tool or retrieved on wireline through the running string.

Abstract: A subsea production tree has an external annular profile formed on an upper portion of the tree. A vertical passage extending from a lower end of the tree to an upper end of the tree for communicating with a string of tubing extending into the well. A lateral passage in the tree extending from the vertical passage. A flow path in fluid communication with the lateral passage extends laterally from the tree, the flow path having an upward facing receptacle. An adapter lands on the upper portion of the tree and connects to the profile, the adapter having a passage that registers with the vertical passage of the tree while the adapter lands on the tree. A flow interface device mounts to and lands with the adapter, the flow interface device having an inlet conduit and an outlet conduit, one of the conduits being connected to the passage in the adapter, the other of the conduits stabbing into sealing engagement with the receptacle as the adapter lands on the tree.

Abstract: A pressure driven pumping system includes a piston disposed within a first bore of a housing to separate a process chamber from a working chamber. A rod member coupled to the separating member extends into a reduced pressure chamber. The piston has a first face exposed to the process chamber and a second face exposed to the working chamber. The second face has an effective area less than an effective area of the first face. The housing may be placed in seawater at a selected depth. The process chamber can be in fluid communication with a well to pass well fluid into the process chamber at well pressure to move the piston, to discharge seawater from the seawater chamber. The working fluid, typically seawater in a subsea application, is pumped into the working chamber to move the piston, which discharges well fluid from the process chamber.

Abstract: A method and system for performing intervention and workover operations on a subsea well are provided, as well as an adapter for connecting a lower end portion of a conduit extending from a vessel with an upper portion of a lower marine riser package associated with a subsea tree. The method includes providing a lower marine riser package connected to an upper portion of a subsea tree associated with a subsea well, and a conduit extending from a vessel toward the lower marine riser package. The conduit is connected to the lower marine riser package with an adapter. A portion of a conduit bore of the conduit above the adapter is sealed from a chamber in the adapter, and a portion of a bore extending through the lower marine riser package is sealed from the chamber. The adapter is opened for access to the chamber from the sea.

Abstract: An apparatus and corresponding method of use extracts, cools, and transports effluents from subterranean, sub-sea oil formations to distant shore based processing facilities. The effluents, mostly crude oil, are conveyed rapidly to a cold flow generator near the oil wellhead on the sea bottom using the cold seawater to chill the effluents to a dispersed mixture including generated solids. The mixture is transported close to sea bottom temperatures, slowly, with small pressure drops, in low-cost submerged bare pipes over long distances to on or near shore processing facilities that can produce useful hydrocarbon products more cost effectively than at sea processing facilities. The apparatus eliminates or minimizes the need for heated or insulated pipe, the need for large floating processing structures, the need for sub-sea processing equipment, and/or the need for chemical additions to production flow.

Abstract: A flow diverter tool assembly is employed for flushing debris from a portion of the bore of a subsea production tree. The flow diverter tool assembly has a housing having a passageway there-through and a seal disposed on an exterior surface of the housing. The seal contacts the inner wall surface of the bore of the production tree, dividing a lower portion of the bore below the seal from an upper portion of the bore above the seal. One or more outlets from the passageway through the exterior surface are disposed along the housing below the seal. A bypass device such as a slip-joint is disposed above the seal to facilitate removal of the flow diverter tool assembly from the bore of the production tree after its use.

Abstract: A ROV-deployable gas hydrate diverter comprising a body having a circular disc shape with a center hole, and a handle attached to and protruding from a surface of the body, wherein the handle is adapted to be grasped by the grasping arm of an ROV to facilitate installation of the gas hydrate diverter over a subsea wellhead.

Abstract: A power slip extends a joint from tubing disposed in casing at a well so that a casing head can install on the casing and the tubing can be packed-off from the casing. The joint attaches to an inner sleeve having collet members that fit onto the inner tubing so that the joint extends thereabove. An outer sleeve and interlocking collet assemble together and install onto the inner sleeve. The collet threads onto the inner sleeve and forces the outer sleeve downward onto the inner sleeve. Being forced, the outer sleeve causes the collet members to engage around the inner tubing. The casing head then installs on the casing with the joint extending up through the head's bowl. An H-plate installs in the open bowl around the extended joint, and another pack-off installs on the joint to pack it off from a spool attaching to the casing head.

Abstract: A subsea wellhead assembly provided over a wellbore, the assembly having a wellhead housing, a tubing hanger in the housing, a production tree on the wellhead housing above the tubing hanger, and a control circuit that passes axially downward from the production tree and through the tubing hanger. A tree stab assembly may be included that is set between the tubing hanger and production tree. The wellhead assembly can also include a casing hanger landed in the housing, casing attached to the casing hanger, and tubing attached to the tubing hanger.

Abstract: In accordance with certain embodiments, the present inveniton provides a connector for attaching to a multi-toothed profile on a wellhead features a tooth profile that staggers loading preferably starting at a loading surface furthest from the connector body sitting on the wellhead and moving toward the connector body. The staggered loading more evenly distributes stresses on the matching loading surfaces as compared to the result of using a tooth profile on the connector that nearly exactly matches the profile on the wellhead. The joint can then take advantage of an increased preload and exhibit improved stress characteristics when operating at high loading conditions.

Abstract: Pressure-balanced accumulator apparatus for use in subsea operations is disclosed which comprises a housing and an accumulator within the housing at the first end of the housing. The accumulator has first and second chambers that are hermetically sealed from one another, with a pressurized gas in the first chamber and a pressurized fluid in the second chamber. A third chamber in the housing abuts the accumulator and contains silicon oil fluid. A movable piston is located within the housing proximate the second end of the housing. Ambient pressure is communicated to one end of the piston, and ambient pressure plus the pressure in the second chamber is communicated to the second end of the piston. The cross-sectional areas of the two ends of the piston are selected to optimize the pressure at which the piston begins to expel fluid from the second chamber.

Abstract: A retrievable tree cap for use on a subsea tree having a concentric bore. The tree cap may be installed and retrieved using a remotely operated vehicle. Hydraulic pressure may be used to lock the tree cap onto the subsea tree and to set the tree cap seals. The tree cap is locked onto the subsea tree before setting the seals within the concentric bore. The tree cap includes a locking means that may engage a profile within the subsea tree regardless of the radial orientation of the tree cap. The tree cap may be used to hydraulically isolate an annulus bore from the production bore of the subsea tree. The tree cap may provide for the injection of a corrosion inhibitor within a cavity of the tree cap and may also provide for the removal of water trapped between the tree cap and the subsea tree.

Abstract: A subsea well production system has a natural drive mode and a lift-assist mode using a submersible pump. The submersible pump can be installed while the well is live. The well system has a downhole safety valve in the production tubing. The operator closes the downhole safety valve and lowers an electrical submersible pump assembly into the production tubing. Once landed, the valve is opened and the pump assembly placed in operation.

Abstract: A system includes a Christmas tree assembly mounted to a hydrocarbon well, an optical feedthrough module, and a plurality of optical sensors. The optical feedthrough module is operable to communicate through a pressure boundary of the Christmas tree assembly. The plurality of optical sensors is disposed within the Christmas tree assembly for measuring parameters associated with the Christmas tree assembly and is operable to communicate through the optical feedthrough module.

Abstract: Apparatus and methods for insulating a connector that connects a first tubular member having a first flange with a second tubular member having a second flange. The apparatus comprises a generally tubular body forming a generally tubular cavity therein adapted to enclose the connector. The body has a longitudinal opening adapted to receive the first tubular member and a closure member for closing said opening. The body and the closure member are lined with insulation and include first and second seals for sealing with the first and second flanges so as to seal around the connector.

Abstract: The invention concerns a dual-type plug to be used in a wellhead. The plug has a separate retrievable inner plug (50). Retrieving only the inner plug allows the use of lighter workover equipment than if the whole plug (10) must be pulled.

Abstract: A subsea gas compressor module having a housing comprising a sealing element generally defining within the pressure housing a first compartment holding as compressor and a second compartment holding an electric motor, the compressor and motor being driveably connected by at least one shaft. The first compartment is connected to an inlet line and an outlet line for sealing hydro carbon gas and for discharging gas. The second compartment has magnetic bearings for supporting the at least one shaft, and a pressure and volume regulator is fluidly connected to the second compartment and a gas supply, and includes elements for sensing respective pressures in the inlet and outlet lines whereby, based on the magnitude of sensed pressure, the pressure and volume regulator controls the pressure at which gas is injected into the second compartment.

Abstract: A hydraulic control system for controlling an external device (4) at a well installation includes a control module (2) for generating electrical and/or optical control signals. A control pod (8) receives the control signals, the control pod controlling the external device. A hydraulic line (10) links the control pod to the external device (4) for controlling it.

Abstract: A subsea wellhead assembly has separable tree modules that interconnect together. The lower tree module has a lower tree member having a bore with a valve for controlling production fluid flow. The upper tree module has an upper tree member with a bore and interface devices for monitoring the fluid flow as well as controlling the flow. A production line sub is carried alongside the upper tree member. The sub has a stab interface that stabs sealingly into a stab interface mounted alongside the lower tree member.

Abstract: A tool is employed with a subsea wellhead assembly for preventing the collapse of a wear bushing located in a drill-through tubular member due to external test forces being applied to it. The tool has a connector that connects to the drill-through tubular member. A stem extends downward from the connector and has a reacting member at its lower end. The reacting member engages an inner diameter of the wear bushing to resist inwardly directed forces due to fluid pressure on the exterior of the wear bushing. The tool can be incorporated with a running tool or with a blowout preventer isolation test tool.

Abstract: A method and system for retrieving a wear bushing from within a subsea wellhead assembly. The system includes a retrieval tool deployable on a wireline that inserts within the bushing. Latches on the tool radially project outwards and mate with a groove on the bushing inner surface. A hydraulically actuated jack is included with the tool and projects downward to the wellhead assembly to pull the bushing from its temporary coupling in the wellhead assembly. A remotely operated vehicle can be used to assist deploying the tool and for supplying hydraulics and/or control for operating the latch and the jack.

Abstract: A wellhead connector for connecting a riser or production tree to a wellhead of a subsea well utilizes a singular annular piston to lock the connector onto the wellhead. The wellhead connector includes a housing that contains dogs for engagement with the exterior of the wellhead housing. A cam ring is also included, which has an inner side for engaging the dogs and moving them inward into a locked position with the wellhead housing. The cam ring is of a reduced proportion relative to prior art. As such, the cam ring outer side is dimensioned to contact the inner side of the connector housing under load. Connecting rods connect the piston to the cam rings. As the piston moves downward, the cam ring also moves downward, forcing the dogs inward into a locked position. As the piston moves upward, the cam ring also moves upward, thereby unlocking the connector. A secondary annular piston is also provided to guarantee unlocking.

Abstract: A cap for a subsea tree having a re-entry hub (1) and for use with a tubing hanger (25) deployed within the tree comprises an outer sleeve (3) for fitment over the hub and an inner sleeve (19) adapted to extend within the hub. The sleeve has communication couplers (27, 37) for cooperation with the tubing hanger. Preferably the communication couplers are located at the extremity of the inner sleeve. The couplers can accommodate dummy plugs or live couplers to suit the mode of application. The inner sleeve (19) supports at least one annular seal (21, 22) which provides a barrier between the inner sleeve and the inner periphery of the hub. The outer sleeve (19) includes releasable engagement fittings (16) for securing the outer sleeve to the hub. The cap is adapted for use as a running tool.

Abstract: Pressure-balanced accumulator apparatus for use in subsea operations is disclosed which comprises a housing and an accumulator within the housing at the first end of the housing. The accumulator has first and second chambers that are hermetically sealed from one another, with a pressurized gas in the first chamber and a pressurized fluid in the second chamber. A third chamber in the housing abuts the accumulator and contains silicon oil fluid. A movable piston is located within the housing proximate the second end of the housing. Ambient pressure is communicated to one end of the piston, and ambient pressure plus the pressure in the second chamber is communicated to the second end of the piston. The cross-sectional areas of the two ends of the piston are selected to optimize the pressure at which the piston begins to expel fluid from the second chamber.

Abstract: The device described herein combines a subsea wellhead and a tree mandrel into a single piece. The wellhead includes a tree valve block having an upper and lower section. The lower valve block section is integral with the wellhead and includes access between the production line and the tubing annulus to the main bore of the wellhead.

Abstract: A wellhead assembly includes a tree cap having a production mandrel extending down into a production passage of a Christmas tree to form a seal. The tree has an annulus bore and an annular cavity at the upper end of the tree surrounding the upper ends of the production and annulus bore. A communication gallery leads between the annulus bore and the cavity. The tree cap also includes an annular sealing member that enters the cavity for sealing a communication gallery.

Abstract: In accordance with certain embodiments, the present invention provides a connector for attaching to a multi-toothed profile on a wellhead features a tooth profile that staggers loading preferably starting at a loading surface furthest from the connector body sitting on the wellhead and moving toward the connector body. The staggered loading more evenly distributes stresses on the matching loading surfaces as compared to the result of using a tooth profile on the connector that nearly exactly matches the profile on the wellhead. The joint can then take advantage of an increased preload and exhibit improved stress characteristics when operating at high loading conditions.

Abstract: An internal tree cap having a running configuration and a latched configuration to be selectively secured to a tree spool. The tree cap may include an inner sleeve movable between upper and lower positions. The movement of the inner sleeve to the lower position may simultaneously engage a locking profile within the tree spool and energize a sealing element around the exterior of the tree cap. The tree cap may be a low profile tree cap that is flush with the top of the tree spool when installed. The tree cap may provide a collateral beneficial locking means to secure a tubing hanger within the tree spool. A lower housing may be attached to the tree cap to seal on the exterior of the upper neck of the tubing hanger. The tree cap may include a profile to accept a wireline plug.

Abstract: A subsea wellhead assembly has a tubing annulus path that extends partly through the tubing hanger and partly through the wellhead housing. A tubing hanger tubing annulus passage extends through part of the tubing hanger from a lower port on the lower end of the tubing hanger to an upper port on the exterior surface of the tubing hanger below the tubing hanger seal. A wellhead housing tubing annulus passage within the sidewall of the wellhead housing has a lower end at the bore below the tubing hanger seal and an upper end at the bore above the tubing hanger seal. A valve is mounted to the wellhead housing and accessible by an ROV from the exterior for opening and closing the inner wellhead housing tubing annulus passage.

Abstract: A subsea wellhead assembly includes a wellhead housing, a production tree, a tubing hanger adapted to land in the wellhead assembly inside the wellhead housing without a need for angular orientation, a bridge member on the tubing hanger in the production tree, a port radially formed through the tubing hanger or the bridge member, a production port radially through the tree head housing, and an annular production flow passage that circumscribes the bridge member lower portion on one end and optionally circumscribes the tubing hanger on its other end. The annular production flow passage is in communication with both the production port and the radial port in the tubing hanger or bridge member so that fluid can be produced from the well via the annular production flow passage without necessity to orientate the tubing hanger.

Abstract: A tubing hanger suspension assembly for an oil and gas well completion system and a method of installing same. The tubing hanger suspension assembly includes a tubing hanger housing which is positioned in the wellhead housing. The tubing hanger assembly includes a sealing and lockdown mechanism capable of providing sealing and load support of the production tubing in the production casing string. A stab sub assembly connected to the upper end of the tubing hanger suspension assembly and lower end of the Christmas tree assembly provides downhole hydraulic and electric functionality and annulus access to the production tubing.

Abstract: A subsea wellhead assembly that includes a wellhead housing, a production tree, a tubing hanger adapted to land in the wellhead assembly inside the wellhead housing, and a bore formed through the production tree having an inner diameter greater than the tubing hanger outer diameter. A hanger adapter may be included having an annular body disposed on the tubing hanger upper surface and a flange member projecting radially outward from the annular body.

Abstract: A wellhead assembly having a data sensor circuit for transmitting sensed data from within a wellbore to the well surface. The circuit includes a signal conduit axially inserted within the wall of a stab unit with connectors at the top and bottom portions of the stab unit. Corresponding connection leads are included within the wellhead assembly to connect with the stab unit connectors. The connectors may comprise a gallery ring wet connect.

Abstract: A removable module for actuating elements, such as valves, within a subsea production tree. The module can include a motor, a drive shaft, and a ball screw. Embodiments exist where only the motor is removable, optionally the motor and drive shaft and/or all module elements are removable. A fail safe system is included that moves the production tree element into a pre-designated fail safe position.

Abstract: A completion system, and a corresponding method, for completing a subsea well, where the well includes a wellhead and a tubing hanger disposed in the wellhead and supports a string of production tubing, allows for angular alignment-free assembly of the subsea well. The completion system includes a series of circumferential channels formed in a well completion device at a boundary between the tubing hanger and the well completion device. The circumferential channels provide complete circular fluid paths with respect to the tubing hanger and the well completion device. At least one supply bore is in communication with each circumferential channel and is and oriented to supply a fluid to the circumferential channel, and at least one drain bore in communication with each circumferential channel and is oriented to remove fluid from the circumferential channel. Finally a circumferential electrical connector couples the tubing hanger and the completion device.

Abstract: A system for controlling gas in a subsea drilling operation is disclosed in one embodiment. The system includes a subsea blow-out preventer, riser coupled to the blow-out preventer, a gas sensor, a controller, and a signal pathway. The gas sensor is configured for placement below the riser and configured to contact wellbore fluids during normal drilling operation. The controller configured to automatically cause manipulation the blow-out preventer based upon information from the gas sensor. The signal pathway couples the gas sensor with the controller.

Abstract: A dual bore well jumper establishing fluid communication between a subsea well and a subsea flowline. The dual bore well jumper comprises a first pipe comprising a first pipe bore and a second pipe comprising a second pipe bore, the second pipe being located within the first pipe bore or side-by side with the first pipe. The dual bore well jumper further comprises termination couplings at each for establishing fluid communication with either the subsea flowline or the subsea well. The first and second pipe bores isolate fluid flow in the first pipe bore from fluid flow in the second pipe bore. The dual bore well jumper may optionally further comprise junction assemblies allowing a change in fluid flow direction. The dual bore well jumper may further optionally comprise a bore access module attached to a junction assembly for selective fluid communication with the first and second bores.

Abstract: A subsea production system on a sea floor has a pump flowline jumper with a straight intermediate portion and two end portions. Each end portion has a connector for ROV assisted connection between production units. A submersible pump assembly is mounted in the straight portion of the flowline jumper and is lowered along with the flowline jumper into engagement with the production receptacles. The pump assembly boosts pressure of fluid flowing from one of the receptacles to the other. A gas separator may be mounted in the same flowline jumper or in a separate flowline jumper.

Abstract: A utility skid tree system for subsea wellheads enables a tree to be mounted by and interface with utility skids. Production bore access is provided through an extended production wing block. The system reacts and transfers installation loads and potential snag loads to the conductor. The tree accepts skids for flow boosting, metering, water-oil separation, etc. A conventional choke may be fitted outboard of the utility insert profile.