Abstract: The system includes a containment housing with an open bottom which is configured to fit over an undersea oil well pipe which is spilling oil, the housing being lockable to a platform or ring surrounding the oil well pipe or positionable on the sea floor. A pipe is positioned internal of the housing into which the oil well pipe can be fitted, the vertical pipe being directed to or connectable to an evacuation pipe which extends to the surface of the sea, through which the oil from the well moves by means of an evacuation pump. The oil is pumped at a rate approximately at least as great as the rate of the oil spill. An infusion line and associated pump is connected to the chamber for pumping mud and/or cement and/or concrete into the chamber to stop and seal the spill and to ensure the housing remains positioned over the oil spill well pipe.

Abstract: Two functionally and physically integrated subsystems form a supplemental disaster preventive system for offshore oil wells. A multi-function well subsystem modifies the sea-floor and in-well equipment to provide maintenance access, tools to cap the well, seal/re-seal the well, drill/re-drill the well, kill the well from the top, improve BOP reliability, add BOP functional redundancy, improve the cementing process, incorporate a sea-floor pressure relief/diversion function and improve the well's life cycle safety. A dome top cylindrical sidewall structure encloses the well's sea-floor equipment providing improved structural strength as well as passive protection from natural/human induced disasters. An intrusion detection and response subsystem provides sensing, processing and communication devices to detect, track & classify the 3D aspects of air/surface/sub-surface objects around a specific oil well or group of oil wells and provides the means to evaluate and eliminate threats.

Abstract: A method and apparatus are described for exploiting the crushing power of the ocean, the principle of the lever, and the weight of a deep-sea oil drilling rig to provide a mechanism that is the simplest and most rapidly deployable way possible to plug a subsea leak. This mechanism for plugging subsea leaks has an inflatable plug and a folding reinforcement mechanism that are contained in a streamlining sheath so that they can be inserted into a leaking high-pressure subsea pipe, and a housing that, in a controlled manner, can be crushed by subsea water pressure to force fluid into the inflatable plug to cause it to inflate to plug the leak; and, depending on the pressure in the pipe, there is a weight basket available that can easily add weight to the mechanism, if necessary.

Abstract: A flow regulator includes a flow regulating part configured to receive at an inlet a working fluid at a first pressure and to release the working fluid at an outlet at a second pressure; a slide provided inside the flow regulating part and configured to move along an axis to reduce the pressure of the working fluid; a control part attached to the flow regulating part, the control part including a chamber; a spring housing provided in the chamber and connected to the slide though a shaft, the spring housing configured to move the slide along the axis; a cap provided in the chamber and facing the spring housing, the cap being configured to have plural blind holes; and plural pins extending along the axis and attached to the spring housing, the plural pins being configured to enter the plural blind holes.

Abstract: A subsea mud pump can be used to return heavy drilling fluid to the surface. In order to provide a less stringent requirement for such a pump and to better manage the bottom hole pressure in the case of a gas kick or well control event, the gas should be separated from the drilling fluid before the drilling fluid enters the subsea mud pump and the pressure within the separating chamber. The mud pump suction should be controlled and kept equal or lower than the ambient seawater pressure. This can be achieved within the cavities of the subsea BOP by a system arrangement and methods explained. This function can be used with or without a drilling riser connecting the subsea BOP to a drilling unit above the body of water.

Abstract: A well containment system is described, the system comprises a blow out preventer, the blow out preventer defining a throughbore and including at least one well containment barrier adapted to seal the throughbore, at least one first seal adapted to seal against the lower end of a riser, and at least one second seal adapted to seal against the upper end of a downhole tubular wherein the at least one first seal is located above the at least one well containment barrier and the at least one second seal is located below the at least one well.

Abstract: There is provided a high power shear laser module, which can be readily included in a blowout preventer stack. The shear laser module as the capability of delivering high power laser energy to a tubular within a blowout preventer cavity, cutting the tubular and thus reducing the likelihood that the tubular will inhibit the ability of the blowout preventer to seal off a well.

Abstract: There is provided a high power laser assisted blowout preventer and methods of use. In particular, there are provided systems and assemblies for utilizing high power laser energy within a blowout preventer to cut tubulars that are present within the bore of the blowout prevent, reducing the risk that such tubulars will inhibit the ability of the blowout preventer to seal a well.

Abstract: There is provided a high power laser riser blowout preventer system and controller for operation thereof. The system utilizes high power laser cutters that are associated with the riser and the blowout preventer to provided an integrated operation to quickly weaken or cut tubulars to address potential emergency and emergency situations that can arise during deep sea drilling.

Abstract: A computerized monitoring system and corresponding method of monitoring the status and health of a blowout preventer. The system includes a graphics display at which a graphical user interface (GUI) displays the health of various sealing elements and control systems by way of “traffic light” indicators. The health indicators are evaluated, by the monitoring system, based on a risk profile for each of the indicated elements and control systems. The risk profiles are evaluated based on inputs such as measurement inputs, feedback signals, mechanical positions, diagnostic results, drilling conditions, and other status information of the blowout preventer at a given time and based on levels of redundancy and levels of deviation from normal conditions. The GUI includes recent history of changes in operating condition, and alarm indications such as poor health, along with the times of those events.

Abstract: A subsea safety system (50) for use during a well treatment operation. The subsea safety system (50) includes a tubular string having an inner flow passage (112). At least one valve assembly (116, 134) is positioned within the tubular string. The valve assembly (116, 134) is operable between open and closed positioned to selectively permit and prevent fluid flow therethrough. A frangible liner (134) is disposed within the valve assembly (116, 134). The frangible liner (134) has a close fitting but not fluid tight relationship with the valve assembly (116, 134). The frangible liner (134) is operable to protect the valve assembly (116, 134) from particle flow during the well treatment operation. In addition, the frangible liner (134) is operable to shatter responsive to closure of the valve assembly (116, 134), thereby allowing full operation of the valve assembly (116, 134).

Abstract: Year 2010 showed us that the oil/gas industry was not prepared to shut down in few days a high pressure oil/gas well. The Gulf of Mexico was polluted by thousands of barrels of oil that were leaking from a high pressure well. The environment damage was humongous as well as the economical loses. Here, I am presenting a method to shut down a high pressure oil/gas well in matter of days rather than in months. This method keeps the well integrity. This method is effective even if the well integrity was compromised.

Abstract: A subsea pressure control system can include at least one subsea choke which variably restricts flow of drilling fluid from a well annulus to a surface location, the choke being positioned at a subsea location, and a subsea process control system which automatically operates the subsea choke, whereby a desired pressure is maintained in the well annulus. Another subsea pressure control system can include at least one subsea choke which variably restricts flow of drilling fluid from a well annulus to a surface location, the choke being positioned at a subsea location, and a subsea pump which pumps the drilling fluid from the subsea location to the surface location.

Abstract: A containment system having a containment dome and a seal plate which is attached to an oil wellhead casing or riser to prevent oil spills and contamination when an oil leak occurs. The containment dome is sealed to the seal plate by a compression mechanism so that oil will not leak from the containment dome. The containment dome can provide a wellhead patch to a wellhead system wherein the wellhead patch can interface with a capping stack. Chemicals can be injected into the containment dome to prevent hydrates from forming. All aspects of controlling and operating an oil wellhead can be performed through the containment dome and seal plate, and all aspects of installation, regulation, and control of the containment dome can be performed by remote operating vehicles under water.

Abstract: A first method of controlling underwater oil well leaks is to place heavy metal javelins into the ruptured pipe. A second method is to fabricate or drop a series of self-stacking exterior collars around or over the ruptured pipe.

Abstract: Methods and systems for a backup emergency disconnect signal (EDS) transmission in an offshore oil and gas installation are provided. A backup EDS transmission system includes a pressure pulse generator located close to a water surface and configured to generate a predetermined pressure variation pattern including at least one of positive and negative pressure pulses and corresponding to an emergency disconnect signal, the signal being propagated downwards in a mud column. The pressure pulse generator is located at a surface end of the mud column. The backup EDS transmission system also includes a pressure pulse receptor connected to a controller of blowout preventers and configured to measure a pressure in the mud column, at a subsea location.

Abstract: Wellhead-based systems, apparatus, and methods for controlling a well are provided. During a failure of an emergency system such as a blowout provider, a wellhead based emergency control apparatus according to an embodiment of the invention can be employed to control the well. A casing strings compression assembly can radially compress each of the casing strings and/or drilling pipe extending through the wellhead housing to restrict or stop well fluid passage. A casing strings penetrator of an emergency well fluid diversion assembly can also or alternatively be employed to form an aperture in the casing strings. A diverter, integral with or connected to the penetrator, is extended through an aperture in a side of the wellhead housing and one or more of the apertures cut by the penetrator to divert well fluid from within the wellhead housing through a passageway in the diverter and to an external conduit.

Abstract: Method and deadman test circuit for testing a functionality of a shearing blowout preventer. The circuit includes a solenoid valve configured to be electrically controlled and to receive a fluid under a first pressure; a sub plate mounted valve configured to be hydraulically controlled by the solenoid valve and to receive the fluid under a second pressure; and a selector valve fluidly connecting an output of the sub plate mounted valve to a shearing blowout preventer and to a device. The selector valve is configured to be operated by an operator.

Abstract: Systems for accessing a well bore including a BOP stack with a universal intervention interface are disclosed. In some embodiments, the system includes a BOP stack and a valve assembly. The BOP stack has a throughbore and is installable on a well such that the throughbore is in fluid communication with the well bore. The valve assembly is coupled to the BOP stack and includes a fluid flowpath in fluid communication with the BOP stack throughbore, two valves connected in series and disposed along the fluid flowpath, the valves operable to control flow through the fluid flowpath, and a ROV panel including ports accessible by a ROV for operation of the two valves.

Abstract: A method and apparatus are described for containing an oil spill caused by a subsea blowout, (i.e., a source of pollution located on a floor of an ocean, (e.g., a defective blowout preventer (BOP) that caused the oil spill)). A cylindrical containment assembly may be positioned such that a wall of the cylindrical containment assembly circumvents a portion of a floor of an ocean where the subsea blowout occurred. At least one mud flap may be configured to selectively protrude from the wall or retract into the wall when activated to control the depth that the cylindrical containment assembly sinks to below the ocean floor. A valve assembly may be positioned on the top perimeter of the wall. The top perimeter of the wall may have the same diameter as the outer perimeter of the valve assembly.

Abstract: System and method for controlling a blowout preventer (BOP) stack and a tree attached to a wellhead of a well. The system includes at least a MUX pod configured to receive electrical signals and a fluid under pressure, and to provide a first set of functions to the LMRP part, and a second set of functions to a lower BOP part; a pod extension module configured to receive the fluid under pressure from the MUX pod, and to provide a third set of functions to the tree based on the received fluid under pressure; and a control part configured to be attached to the tree and to communicate with the pod extension module. The third set of functions for the tree is different from the second set of functions provided to the lower BOP part.

Abstract: A method and apparatus are described for containing an oil spill caused by a subsea blowout. A blowout preventer (BOP) stack, located on a floor of an ocean, may be circumvented with a hollow wall of a cylindrical containment assembly. The containment assembly may be reinforced by filling the wall with cement. A valve assembly having a hollow cavity may be positioned on a top perimeter of the wall and may be reinforced by filling the cavity with cement. Alternatively, a cylindrical containment assembly may be positioned such that a wall of the assembly circumvents a portion of a floor of an ocean where a subsea blowout occurred and at least one of oil or gas is spewing into the ocean. The wall may be reinforced with cement, a valve assembly may be positioned on a top perimeter of the wall, and the valve assembly may be reinforced with cement.

Abstract: A collector for capturing flow discharged from a subsea blowout includes a tubular housing having a containment chamber; a seal connected to the housing; a tubular chimney connected to the housing, having a portion of a subsea connector, and having a diameter less than a diameter of the containment chamber; and a head connected to the housing and the chimney.

Abstract: Production and drilling may be achieved by a system which uses a rotating head coupled to surface blowout preventer stack for fluid flow control. A casing connects these surface components to a subsea shutoff assembly with a pair of ram shear devices to cut off the string to the wellhead. Both the casing and an alternate line may be latched so that they may be released if necessary. The rotating head may include a rubber packer to prevent upward flow of drilling fluid and production hydrocarbons and, at the same time, provide rotation to the drill string. Managed pressure drilling or under balanced drilling may be used in some embodiments.

Abstract: An emergency control system (ECS) for a subsea blowout preventer (BOP) includes a frame having a mud mat for engaging a seafloor; an ECS accumulator connected to the frame; a BOP interface connected to the frame and operable to connect to a stack interface of a BOP stack; a valve connected to the frame and operable to supply hydraulic fluid from the ECS accumulator to the interface; an acoustic receiver; and a controller operable to receive an instruction signal from the acoustic receiver and open the valve.

Abstract: A method for installing a pipe closing apparatus in an oil well rig system positioned at least partially in a body of water, comprising the steps of shutting off a flow of oil through a well head, removing a section of riser pipe from the oil well rig system and connecting the pipe closing apparatus to a remaining portion of riser pipe and positioning the pipe closing apparatus between the remaining portion of riser pipe and the well head.

Abstract: An umbilical field connect assembly comprising: a first umbilical portion comprising two or more first bundled members chosen from electrical cables, fluid conduits, and optical fibers; a second umbilical portion comprising two or more second bundled members chosen from electrical cables, fluid conduits, and optical fibers; a first housing assembly having a first end coupled to the first umbilical portion and a second end comprising a first coupling plate having a plurality of first couplings chosen from male and female couplings positioned therein, one of the plurality of first couplings being positioned at an end of each of the first bundled members; a second housing assembly having a third end coupled to the second umbilical portion and a fourth end comprising a second coupling plate having a plurality of second couplings chosen from male and female couplings positioned therein, one of the second couplings being positioned at an end of each of the second bundled members.

Abstract: A subsea connection apparatus to allow connecting a surface blowout preventer stack and riser to a subsea wellhead is disclosed. The subsea connection apparatus uses a single cavity blowout preventer with a set of shearing blind rams. Hydraulically actuated wellhead connectors are secured to the top and bottom of the blowout preventer to allow connection to a subsea wellhead below the subsea connection apparatus and a well head hub profile on the lower end of a riser above the apparatus. A control system can operate both of the hydraulically actuated connectors and the blowout preventer independently. A frangible bore protector is disposed in the bore of the blowout preventer to protect the shearing blind rams from pipe, tools, and fluids being passed through the blowout preventer and can be sheared by the shearing blind rams along with any drill pipe in the bore.

Abstract: A pair of rescue vehicles are deployed on deployment cables to force the shear ram of a sub-sea BOP to shut if it should malfunction. The rescue vehicles may be provided with a camera for remote operation from the surface. The rescue vehicles include securing arms to mate with receiving means on the BOP or its enclosure. The securing arms actuate hydraulic means to release the BOP shear ram piston from hydraulic lock. The rescue vehicles carry their own hydraulic fluid under pressure, or hydraulic fluid pressure may be supplied from the surface or from an ROV, in order to actuate a rod which strikes the accessible BOP shear ram tail rod, forcing the shear ram shut. The rescue vehicles also carry their own securing wedges to slide down behind the vehicle rod, securely holding the BOP shear ram shut.

Abstract: A subsea well safing method and apparatus adapted to secure a subsea well in the event of a perceived blowout in a manner to mitigate the environmental damage and the physical damage to the subsea wellhead equipment to promote the ability to reconnect and recover control of the well. The safing assembly is adapted to connect the marine riser to the BOP stack. Pursuant to a safing sequence, the well tubular is secured in the upper and lower safing assemblies and the tubular is then sheared between the locations at which it as been secured. Subsequently, an ejection device is actuated to physically separate the upper safing assembly and connected marine riser from the lower safing assembly that is connected to the BOP stack.

Abstract: Various embodiments of underwater wellhead closure systems are described that include a template having first and second anchoring ports and that is configured to be secured to a floor of a body of water. A suction pile having a cylindrical body with a head portion and an open bottom can be coupled to the first anchoring port, such that the suction pile can provide additional hold down force to the template. The system can also include a suction cap coupled to the second anchoring port, and having a cylindrical body with an open bottom and a head portion having at least one suction pump.

Abstract: An apparatus which includes a housing defining a chamber, the chamber being sealed from an exterior of the housing, wherein the housing further defines an opening in fluid communication with the chamber and the exterior of the housing. The apparatus further includes a valve in fluid communication with the opening and positioned between the chamber and the exterior of the housing and a member at least partially positioned within the chamber and moveable relative to the housing such that opening of the valve allows fluid to enter the chamber from the exterior of the housing and move the member. A method to operate the same is provided.

Abstract: The usual safety feature of oil pipes is the shut-off valve. Whenever there is a need, such a valve can be closed, and oil is prohibited from spilling into the surroundings. However, the shut-off valve may sometimes be inaccessible. It may be buried deep in the mud, or even worse, there may be no shut-off valve. Such an oil spill could prove disastrous. Fortunately, our invention would provide a solution to just such a situation. We would need to send submarine robots to the scene of the accident. These robots, controlled from the ship on the surface, would insert our specially designed hydraulic head into the pipe. This head would then seal the pipe, stopping any further oil spill.

Abstract: Several, preferably three, deflection elements are placed and fixed around the wellhead, preferably in equal circumferential distances around the wellhead. For each deflection element a guiding cable is lowered with its head end from one or several, preferably three workspaces in the direction of the wellhead. Each guiding cable is looped with its head end through the corresponding deflection element, wherein each deflection element forms a point of reversal. Each guiding cable is pulled back with its head end side to the corresponding workspace while in return additional guiding cable is supplied and passed through the corresponding deflection element. A sealing element which is fastened to each guiding cable is lowered in the direction of the wellhead by pulling the guiding cables at their head end sides upwards and, in return, supplying the guiding cables in the direction of the wellhead on the lowering side.

Abstract: A method and apparatus are described for containing oil and/or gas spewing from a defective blowout preventer (BOP) stack located on a floor of an ocean using BOPstopper assemblies. A BOPstopper containment assembly is submerged below a surface of the ocean and positioned on a portion of the ocean floor that circumvents the defective BOP stack. Then, a BOPstopper valve assembly is submerged below the ocean surface and positioned on top of the BOPstopper containment assembly to contain the oil and/or gas. Each of these BOPstopper assemblies may comprise a plurality of flooding valves used to submerge the BOPstopper assemblies. Furthermore, each of these BOPstopper assemblies may comprise a plurality of reinforcement material input valves for reinforcing the assemblies with reinforcement material (e.g., cement and/or mud). The flooding valves and the reinforcement material input valves may be remotely controlled from a vessel floating on the ocean surface.

Abstract: A method and apparatus are described for containing oil and/or gas spewing from a defective blowout preventer (BOP) stack located on an ocean floor. In one scenario, a containment assembly having a hollow wall is lowered below the ocean surface, and positioned on a portion of the ocean floor that circumvents the defective BOP stack. The hollow wall of containment assembly is filled with reinforcement material (e.g., cement). Then, a valve assembly is lowered below the ocean surface and positioned on top of the reinforced containment assembly. The valve assembly has a hollow cavity surrounding at least one large diameter high pressure valve that is maintained in an open position. The hollow cavity of the valve assembly is also filled with reinforcement material (e.g., cement). The large diameter high pressure valve is then closed to contain the oil and/or gas within the reinforced containment assembly.

Abstract: A method and apparatus are described for containing an oil spill caused by a subsea blowout. A cylindrical containment assembly may be positioned such that a wall of the cylindrical containment assembly circumvents a portion of a floor of an ocean where the subsea blowout occurred. A valve assembly may then be positioned on a top perimeter of the wall. The cylindrical containment assembly may form a watertight seal with the ocean floor. At least one mud flap, located on the wall of the cylindrical containment assembly may be activated to control the depth of the cylindrical containment assembly below the ocean floor. Further, a source of pollution, (e.g., a defective blowout preventer (BOP) that caused an oil spill), may be encased by positioning a valve assembly on a top perimeter of a containment wall after the containment wall is positioned to circumvent the source of pollution.

Abstract: A method and apparatus are described for controlling valves of a subsea oil spill containment assembly. In one embodiment, a control unit is configured to control at least one reinforcement material input valve of the subsea oil spill containment assembly. In another embodiment, the control unit is configured to control at least one flooding valve of the subsea oil spill containment assembly. In yet another embodiment, the control unit is configured to control a large diameter high pressure valve of the subsea oil spill containment assembly. The control unit may be configured to control each reinforcement material input valve, flooding valve and large diameter high pressure valve of the subsea oil spill containment assembly, either wirelessly or via a wired interface, such that each valve may be maintained in an open position, a partially open position or a closed position, as desired.

Abstract: Systems and methods for quick access and control of a blown-out well or well that is flowing uncontrollably into the environment. Preferred embodiments of the present invention provide a re-entry of the casing of the blown-out well below the mud line and the inoperable blowout preventer. The present invention also provides a method to re-enter a production, or injection well, either subsea below the mud line or above the mud line for surface facility applications. According to a preferred embodiment of the present invention, a miniature wellbore is created from the outer casing through the various smaller casing strings into the final wellbore to protect the structural integrity of the well. Once the casing is safely penetrated, coil tubing and or kill weight fluid can be introduced to stop the uncontrolled flow of reservoir fluid. The well can then be sealed with cement and abandoned as normal practice dictates.

Abstract: The method of providing increased motive force for one or more rams of a subsea blowout preventer comprising providing a one or more pistons connected to the one or more ram, the pistons having a distal side and a proximate side with respect to the ram, providing a tank contain a first pressure less than the ambient pressure of seawater at the location of the subsea blowout preventer, and communicating the first pressure with the proximate side of the one or more pistons to cause or enhance the differential pressure across the one or more pistons to urge the rams toward the center of the bore of the subsea blowout preventer.

Abstract: A method and apparatus are described for stopping oil and/or gas from spewing from a defective blowout preventer (BOP) stack located on a floor of an ocean by entombing the defective BOP stack. A containment assembly, which is lowered below a surface of the ocean, includes a hollow wall and a large diameter high pressure valve mounted on an upper opening of the containment assembly. The large diameter high pressure valve is maintained in an open position. The containment assembly is positioned on a portion of the ocean floor such that a hollow inner cavity of the containment assembly circumvents the defective BOP stack. The hollow wall is filled with reinforcement material via a first set of valves, and the hollow inner cavity is filled with reinforcement material via a second set of valves. The upper opening may also then be filled with reinforcement material.

Abstract: An apparatus, system and method for releasing fluid from a subsea marine riser is disclosed. A housing defines an interior space and an exterior region. The housing includes first and second ends adapted for respective sealed connection in a marine riser assembly. The housing may be defined on its interior space by a central cavity adapted for passage of a drill string. A plurality of ports may be provided for fluid release from the housing upon emergency disconnect of the riser from a subsea well. One or more gates may be provided in mating configuration with the housing. The gates may be moveable from a sealed position that restricts fluid flow through the ports to an open position that facilitates fluid release from the riser through the ports.

Abstract: A drill ship is provided for conducting subsea operations, including intervention, maintenance and workover operations. The ship includes a hull having a substantially wide beam-to-length ratio and a deckspace. An automated system for handling tubulars and risers is mounted to the deck space, along with a pipe racking system. The deckspace includes a heavy-lift heave crane for handling seafloor operations and a medium duty crane mounted over the deckspace. The ship is configured to provide heavy lift subsea construction operations including 16-inch riser well intervention and workover programs, connected riser completion operations, and riserless tophole drilling and casing operations. The ship is also able to perform connected riser remedial drilling and slim hole well construction. The ship maximizes environmental efficiency in both construction and use, and provides a stable and safe work and living environment for operations personnel.

Abstract: Methods for deploying a subsea blowout preventer stack system comprising a lower marine riser package, a blowout preventer stack with a first ram blowout preventer, and an additional blowout preventer package releasably coupled to the blowout preventer stack and comprising a second ram blowout preventer. The subsea blowout preventer stack assembly can be deployed by coupling a drilling riser to the lower marine riser package that is releasably connected to the blowout preventer stack. The lower marine riser package and blowout preventer stack are then toward a subsea wellhead and then landed on the additional blowout preventer package that is coupled to the subsea wellhead.

Abstract: Apparatus for improving the safety and recovery of wells to be installed in oil wells comprising a Deep Set Well Head (DSWH), a Casing Receptacle (1), a Deep Set Tubing Hanger (DSTH) (2), Sub-Surface Safety Valves (SSSVs) (12) (13) with one or two independent Control Lines and Connection elements between the DSTH and well head

Abstract: An accumulator for a subsea blowout preventer unit including a blowout preventer includes a body. The body includes a hydraulic fluid chamber and a gas chamber. The hydraulic fluid chamber has a smaller inner diameter than the gas chamber. The accumulator further includes a hydraulic fluid port in fluid communication between the hydraulic fluid chamber and the subsea blowout preventer, a hydraulic piston slidably and sealingly mounted in the hydraulic fluid chamber, and a charge piston slidably and sealingly mounted in the gas chamber. A pressure port receives pressure to provide a force on the opposite side of the charge piston from the hydraulic piston.

Abstract: A technique enables protection of subsea wells. The technique employs a subsea test tree designed to ensure control over the well in a variety of situations. The subsea test tree is formed with at least one shut-off valve to protect against unwanted release of fluids from the subsea test tree. The subsea test tree also is coupled with and controlled by a control system having a subsea control module mounted to an interior mandrel.

Abstract: Methods and systems for drilling subsea wells bores with dual-gradient mud systems include drilling the subsea well bore while employing a subsea pumping system, a subsea choke manifold and one or more mud return risers to implement the dual gradient mud system. When a well bore influx is detected, the well bore is shut in, and components determine if pressure control may be used to circulate the influx out of the well bore, the size of the influx, and how much the mud system weight will need to be reduced to match the dual gradient hydrostatic head before the influx reaches the subsea pump take point. The subsea pumping system, subsea choke manifold, and mud risers are isolated while the influx is circulated up one or more fluid passages in the drilling riser package using the surface pump, through the wellhead, and out the surface choke manifold.

Abstract: A method for the extinction or oil well-killing or killing of an underwater well for the extraction of hydrocarbons under uncontrolled fluid discharge conditions, also called blowout, by assembling, in correspondence with the lower end portion of a string of pipes for the extinction or killing string, a constraint group for rigid connection between a plurality of remote-operated underwater vehicles and the killing string; detecting the position of a flow of fluids and positioning the killing string substantially in correspondence with said flow; lowering a plurality of remote-operated vehicles close to the lower end portion of the killing string; connecting the remote-operated vehicles to the constraint group; detecting in real time the relative position of the flow of fluids with respect to the vehicles and calculating the position of the outlet hole of the flow; on the basis of the calculated position of the outlet hole, coordinately piloting the vehicles so as to bring the lower end of the string in corres

Abstract: A subsea cutting device for a subsea blow-out preventer or wellhead comprises a tubular body having an axial throughbore, and configured to be fitted to a casing string, the cutting device further comprising a shearing mechanism in the form of a radial cutting system rotatably mounted within a pressure-containing housing, and comprising a plurality of movable cutters arranged around the throughbore and configured for deployment during rotation successively inwards. The cutting device is useful in a subsea shut off device which is latched to a template at surface and run to the sea floor on a casing string which is drilled into place and converted into a riser on a single trip. For the event when emergency disconnection is required, the device may be used to cut the casing and seal in the well. The system then allows a conventional subsea reconnection of the riser.