Abstract: A power supply assembly, which is placed subsea and is connected to an umbilical from a platform, supplies electrical power to subsea equipment. The power supply assembly supplies power during drilling operations to a pump for pumping drilling fluid from the sea floor to the sea surface. During production operations, the power supply assembly provides power to a booster pump to pump the well fluid away from the subsea well for collection. The subsea power supply assembly optionally also provides power to electrically charged portions of subsea separators that remove water from the oil in the well fluid. The booster pump the pumps the oil from the separator away from the subsea wellhead for collection.

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

Abstract: The present invention generally relates to methods for drilling a subsea wellbore and landing a casing mandrel in a subsea wellhead. In one aspect, a method of drilling a subsea wellbore with casing is provided. The method includes placing a string of casing with a drill bit at the lower end thereof in a riser system and urging the string of casing axially downward. The method further includes reducing the axial length of the string of casing to land a wellbore component in a subsea wellhead. In this manner, the wellbore is formed and lined with the string of casing in a single run. In another aspect, a method of forming and lining a subsea wellbore is provided. In yet another aspect, a method of landing a casing mandrel in a casing hanger disposed in a subsea wellhead is provided.

Abstract: A subsea well intervention vessel including a dynamically positionable tanker and direct well intervention equipment mounted on a deck of the tanker. The direct well intervention equipment is mounted on a superstructure above the main deck of the tanker and includes equipment for underbalanced non-rotating drilling and hydrocarbon liquid separation. The liquid separation equipment is coupled to storage tanks of the tanker so as to receive separated hydrocarbon liquids for storage purposes.

Abstract: A boring device for producing a bore with a casing tube has a linkage, a boring tool, which can be fixed to the lower end of the linkage, a mounting frame for mounting on the casing tube, a drive and a connecting device, which is used for producing a rotary connection between the casing tube and the mounting frame. The linkage is hollow and has a first and a second flushing line. In the vicinity of the upper end of the link-age are provided a first connection for the supply of a fluid to the first flushing line and a second connection for removing the borings via the second flushing line. A boring method introduced the casing tube into the soil prior to an excavation.

Abstract: A floating rig or structure for drilling in the floor of an ocean using a rotatable tubular includes a seal housing having a rotatable seal connected above a portion of a marine riser fixed to the floor of the ocean. The seal rotating with the rotating tubular allows the riser and seal housing to maintain a predetermined pressure in the system that is desirable in underbalanced drilling, gas-liquid mud systems and pressurized mud handling systems. The seal is contemplated to be either an active seal or a passive seal. A flexible conduit or hose is used to compensate for relative movement of the seal housing and the floating structure because the floating structure moves independent of the seal housing. A method for use of the system is also disclosed.

Abstract: The present invention provides drilling systems for drilling wellbores. The drilling system includes an umbilical that passes through a wellhead and carries a drill bit. A drilling fluid system supplies drilling fluid into an annulus (supply line) between the umbilical and the wellbore, which discharges at the drill bit bottom and returns to the wellhead through the umbilical (return line) carrying the drill cuttings. A fluid circulation device, such as a turbine or centrifugal pump, is operated in the return line to provide the primary motive force for circulating drilling fluid through a fluid circuit formed by the supply line and return line. Optionally, a secondary fluid circulation device in fluid communication with the return line can cooperate with the fluid circulation device to circulate drilling fluid and/or a near bit fluid circulation device can be used to provide localized flow control or suction pressure to improve bit cleaning.

Abstract: A subsea well assembly has a guideframe that receives a control pod. The guideframe is in fluid communication with either a blow-out preventer (BOP), a lower marine riser package (LMRP), or both. The control pod is in communication with a vessel, and is used to control the functions of the BOP, the LMRP, or both. Electrical and hydraulic communications are established between the control pod with little or no assistance from a remote operated vehicle. A piston is used to extend a stab assembly into engagement with control panels that are in communication with the BOP and LMRP. The stab assembly can be locked in its upper position while being lowered and landed in the guideframe, and in its lower position after registering with the control panels. Springs and slideable plates help align electrical connections to the BOP and LMRP upon engagement of stab assemblies and stab receptor assemblies.

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

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

Abstract: The invention is a multiple lift hoist system for a drilling vessel and use on land made of a mast with a top side and a base connected to a drilling vessel, wherein the mast has a hollow construction for supporting a first and second hoisting device at the top side, a lift system with a first hoisting device located in a first firing line that manipulates a first drill string and s second hoisting device located in a second firing line that manipulates a second drill string both hoisting devices move the strings in the longitudinal direction of the mast, and a plurality of cables and winches disposed in the hollow construction to manipulate the position of the first and second hoisting devices relative to the mast so the first and second firing lines are accessible from the outside of the mast.

Abstract: The present invention provides drilling systems for drilling subsea wellbores. The drilling system includes a tubing that passes through a sea bottom wellhead and carries a drill bit. A drilling fluid system continuously supplies drilling fluid into the tubing, which discharges at the drill bit bottom and returns to the wellhead through an annulus between the tubing and the wellbore carrying the drill cuttings. A fluid return line extending from the wellhead equipment to the drilling vessel transports the returning fluid to the surface. In a riserless arrangement, the return fluid line is separate and spaced apart from the tubing. In a system using a riser, the return fluid line may be the riser or a separate line carried by the riser. The tubing may be coiled tubing with a drilling motor in the bottom hole assembly driving the drill bit.

Abstract: The present invention generally relates to methods for drilling a subsea wellbore and landing a casing mandrel in a subsea wellhead. In one aspect, a method of drilling a subsea wellbore with casing is provided. The method includes placing a string of casing with a drill bit at the lower end thereof in a riser system and urging the string of casing axially downward. The method further includes reducing the axial length of the string of casing to land a wellbore component in a subsea wellhead. In this manner, the wellbore is formed and lined with the string of casing in a single run. In another aspect, a method of forming and lining a subsea wellbore is provided. In yet another aspect, a method of landing a casing mandrel in a casing hanger disposed in a subsea wellhead is provided.

Abstract: A method of drilling sub-sea oil and gas production wells in which a liquid hydrocarbon substance, such as a natural gas liquid, is injected into the drilling mud supplied to the well in order to reduce the mud density. The method of the present invention enables reduction and control of the hydraulic pressure of the drilling mud while drilling production wells in deep water, thereby to require fewer casing runs which eventually yields better oil productivity.

Abstract: An underwater well system in which an initially vertical drilling riser conduit is fixed by a template at the seabed in a non-vertical orientation. Drilling is carried out through wellhead in the template which also includes a valve tree allowing the production fluid to be brought to the surface along a line separate from the drilling riser conduit. The template may be a junction template allowing several wells to be drilled from a single template, or allowing the template to be connected by one or more drilling conduits to further templates such that a wide area of the seabed can be covered for a single drilling riser conduit.

Abstract: A method of preparing and operating a subsea well (23), comprising the steps of: locating a drill-through subsea tree (24) on a subsea wellhead; sealingly connecting a high pressure drilling riser (22) between the tree and a drilling platform at the sea surface; mounting a blow out preventer (16) at the top of the riser (22); drilling the well through the drilling riser and the subsea tree; and establishing a production connection between the tree (24) and a production collection facility at the sea surface through a production riser (52) which is separate from the drilling riser (22).

Abstract: An apparatus and method for offshore riserless drilling are disclosed. The preferred embodiments comprise a system for riserless drilling of a subsea borehole from a platform and through a cased borehole, the system comprising a lightweight drill string suspending a bottomhole assembly and extending from the platform downwardly through a depth of water into the cased borehole; a first limiter limiting the range of motion of the drill string adjacent the platform; and a second limiter limiting the range of motion of the drill string adjacent the cased borehole. The preferred methods include lowering a bottomhole assembly suspended on a lightweight drill string from a platform through a depth of water; limiting the bend radius of the drill string adjacent the platform; guiding the bottomhole assembly into a cased borehole; limiting the bend radius of the drill string adjacent the cased borehole; maintaining the bottomhole assembly in the cased borehole, and drilling the subsea borehole.

Abstract: A cantilever beam of a jack-up unit is provided with constant force restraining members mounted on a deck of a jack-up unit forward from conventional hold-down cantilever beam clamp. A modified cantilever beam end plate engages a first end of constant force restraining member, which may be a hydraulic cylinder, with the second end of the hydraulic cylinder secured to movable padeye, which is releasably secured to the deck of the jack-up unit. If desired a fixed foundation may be secured to the deck to reinforce the area of attachment of a padeye to the deck. To allow extension of the cantilever beam even farther to a drill well, an extension member may be attached to the end plate between a free end of the end plate and the hydraulic cylinders.

Abstract: Methods and apparatus for drilling subsea wells in deep water using dual-gradient drilling techniques. One preferred embodiment includes a high pressure riser running from a drilling platform at the surface to the seafloor. The base of the riser is connected to a wellhead that is anchored to the seafloor. Pressure control equipment is disposed on the upper end of the riser at the drilling platform. A coiled tubing drill string is run through the riser and into the subsea formation. The drill string preferably includes a pressure sensing device that can be used in transmitting real-time downhole pressure data to the surface. A riser injection system is provided to inject a lower density fluid into the riser annulus in order to reduce the density of the fluids in the riser annulus and therefore reduce the hydrostatic pressure within the wellbore.

Abstract: Methods and apparatus are disclosed for the open hole drilling of a borehole from an offshore platform and through a cased borehole at the seafloor. The drilling assembly includes a guide assembly extending from the platform to the seafloor and having a lower end extending into the cased borehole; and a bottomhole assembly disposed on a lightweight drill string extending through the guide assembly for drilling the borehole. The guide assembly is a pipe string and preferably includes a casing and a riser attached to the casing. The lightweight drill string may be a jointed pipe, a metal coiled tubing, or preferably a composite coiled tubing. The bottomhole assembly includes a formation displacement member adapted to drill a borehole having a diameter greater than the diameter of the guide assembly.

Abstract: The present invention generally relates to an apparatus and method for removing hydrocarbons and other material from a wellbore. In one aspect, a method of drilling a sub-sea wellbore is provided. The method includes circulating a drilling fluid through a drill string from a surface of the sea to a drill bit in the wellbore. The method further includes pumping the fluid and drill cuttings from the sea floor to the surface with a multiphase pump having at least two plungers operating in a predetermined phase relationship. In another aspect, a fluid separator system having a first and a second plunger assembly is provided. The fluid separator system includes at least one fluid line for removing a fluid portion from the at least one plunger assembly and at least one gas line for removing gas from the first and a second plunger assembly.

Abstract: A tubular piling apparatus and method for penetrating the soil comprises, in a preferred embodiment, elements such as a drive shoe and/or other earth displacing structures which may be, in one presently preferred embodiment, of larger outer diameter than the surface conductor pipe. In a preferred embodiment, the invention includes a collar mountable to the pilings having an earth displacing structure formed thereon. In another aspect, a drive shoe, being of a larger size than the conductor pipe and connected to the bottom section of the conductor pipe is provided with an exterior band mounted on the outer diameter of the drive shoe. The exterior band may be located proximate the lower end of the drive shoe. The drive shoe may include teeth formed such that causes compression of earthen formation away from the inner surface of the drive shoe.

Abstract: Systems and methods for time, and labor efficient construction and production of subsea wells include a surface blowout preventer stack, a high pressure riser, and a drill thru Xmas tree. The systems may further comprise a subsea shut off and disconnect device.

Abstract: A method and apparatus for installing conductor casing for offshore oil wells. In the preferred embodiment of the present invention, a retrievable suction embedment chamber assembly drives a string of casing into the seafloor using hydrostatic pressure by releasably forming a seal around the casing to be driven and using a pump to lower the pressure inside the chamber. The assembly may then be flooded with seawater, released from the casing, then repositioned at a higher point on the casing, and the embedment process repeated. The assembly may also be used to embed several subsequent strings of casing in series.

Abstract: A method of installing a pile 10 in a subsea substrate is provided, which method comprises the steps of providing a pile 10 with a drill bit 14 at one end, and rotating both the pile 10 and the drill bit 14 relative to a substrate to form a bore. Also provided is a subsea pile 10 in the form of an elongate member 12 with a drill bit 14 fixed at one end thereof. In certain embodiments, the elongate member 12 may be tubular, allowing fluids to be supplied to the drilling face via the pile. Such fluids may be drilling mud, sea water, or a settable material for fixing the pile in the bore.

Abstract: A method for driving a drive pipe into a subsea formation, the method being comprised of the following steps: suspending the drive pipe from a drill string; moving at least one mass in a direction having an upward component and within the drive pipe; accelerating at least one mass relative to the drive pipe, wherein the at least one mass is accelerated within the drive pipe; transferring energy from the accelerated at least one mass to the drive pipe; isolating the drill string from energy from the accelerated at least one mass; and removing a core of formation from within the drive pipe after the transferring.

Abstract: An offshore drilling rig contains a heavy-duty support cart that straddles the moonpool and rides on rails. A funnel-shaped hole extends through the support cart, and a cutout on one side of the cart provides lateral access to the hole. The cart can be moved to the region of the rotary assembly, where a length of tubulars can be suspended from the cart. For instance, when the BOP is pulled out for installation of the Xmas tree assembly, the BOP and attached riser can be pulled up above the seabed and hung from the support cart, then moved laterally out of the way while the Xmas tree assembly is installed. This lateral movement lowers the possibility of collision between the BOP and Xmas tree assembly. The BOP assembly can then be disassembled and at a later time, or hung until is needed for an adjacent borehole. In a preferred embodiment, the cart is included on multi-activity rigs with more than one load path, hoist, and rotary assembly.

Abstract: An end piece arrangement is mounted on an end of a pipe sleeve to close off the annular passage between the pipe sleeve and drill stem and to divert an upward flow of sludge, cuttings and gas into a conduit system to transport the flow to a remote location. In one embodiemnt, the arrangement is a self-contained unit that houses seal rings to seal against the drill stem. In another embodiment, the arrangement includes separate components; i.e. a housing mounted on the pipe sleeve to divert the upward flow and a seal unit mounted on the drill stem and rotatably mounted in the housing.

Abstract: A method for addressing the problem known as formation breathing occurring during the drilling of a subsea well in an earth formation in performing a series of leak off tests to determine the earth formation fracture propagation pressure and the earth formation fracture reopen pressure and maintaining the hydrostatic pressure on the earth formation in a range between the fracture reopen pressure and the fracture propagation pressure.

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

Abstract: A method is disclosed for controlling pressure in a wellbore during drilling. The method includes operating a drilling system to have a first fluid pressure gradient inside a drillstring extending from the earth's surface to a drill bit at the bottom of the wellbore. The drilling system has a second fluid pressure gradient lower than the first fluid pressure gradient in an annular space between the drillstring and the wellbore from a selected depth in the wellbore to the earth's surface. Introduction of drilling fluid to the inside of the drillstring is stopped, and fluid flow in the annular space from a point below the selected depth to a point above the selected depth is selectively controlled to cause a substantially constant fluid pressure at a predetermined depth in the wellbore.

Abstract: A method and apparatus for controlling drilling mud density at a location either at the seabed (or just above the seabed) or alternatively below the seabed of wells in deep water and ultra deep water applications are disclosed. The present invention combines a base fluid of lesser density than the mud required at the wellhead to produce a diluted mud in the riser. By combining the appropriate quantities of drilling mud with base fluid, a riser mud density at or near the density of seawater may be achieved. The present invention also includes a wellhead injection device for attachment to the wellhead and for injecting the base fluid into the rising drilling mud at a location below the seabed. The riser charging lines are used to carry the low density base fluid to the injection device for injection into the drilling mud below the seabed. The cuttings are brought to the surface with the diluted mud and separated in the usual manner.

Abstract: A drilling system for drilling subsea wellbores includes a tubing-conveyed drill bit that passes through a subsea wellhead. Surface supplied drilling fluid flows through the tubing, discharges at the drill bit, returns to the wellhead through a wellbore annulus, and flows to the surface via a riser extending from the wellhead. A flow restriction device positioned in the riser restricts the flow of the returning fluid while an active fluid device controllably discharges fluid from a location below to just above the flow restriction device in the riser, thereby controlling bottomhole pressure and equivalent circulating density (“ECD”). Alternatively, the fluid is discharged into a separate return line thereby providing dual gradient drilling while controlling bottomhole pressure and ECD. A controller controls the energy and thus the speed of the pump in response to downhole measurement(s) to maintain the ECD at a predetermined value or within a predetermined range.

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

Abstract: Systems and methods for time-, and labor-efficient construction and production of subsea wells are disclosed. The systems generally comprise a surface blowout preventer stack, a high pressure riser, and a drill thru Xmas tree. The systems may further comprise a subsea shut off and disconnect device.

Abstract: This invention provides apparatus and methods for controlling the particle size of the solid mass present in the circulating drilling fluid returning from an underwater wellhead during the drilling of a subsea wellbore. The system may include a separator at the sea floor adjacent the wellhead, which separates solids above a predetermined size from the wellstream. The wellstream then enters one or more underwater pumps, which pump the wellstream to the surface. A crusher, as a separate unit, integrated in the separator or in the pump, receives the separated solids and reduces them to relatively small-sized particles. The small particles are then pumped or moved to the surface by the pumps utilized for pumping the wellstream to the surface or by a separate underwater pump. Alternatively, the separated solids are collected from the separator into a container, which container is then transported to the surface by a suitable method.

Abstract: A method and system for cable-based communication between the drilling rig and the bottom hole assembly is disclosed. A cable is provided along the outside of an upper portion of the drillstring. The cable is connected to a cross-over sub assembly below which is attached a second cable that extends down towards the bottom hole assembly. During drilling the cable rotates with the drillstring, and the unused cable is stored in a reel mounted on the top drive unit. New pipe stands are connected and the cable is clamped to the outside of the drillstring. The method and system are particularly well suited for use in deep-water drilling environments.

Abstract: A method for controlling subsea drilling operations which, in at least certain aspects, includes controlling the subsea drilling operations with a control system having three subsea pod containers of a control system, each with apparatus for controlling the subsea drilling operations, the system also having activation apparatus for activating a chosen one of the subsea pod containers and maintenance apparatus for maintaining the two subsea pod containers other than the chosen one in a standby mode so that triple redundancy of control of the subsea drilling operations is provided, so that the subsea drilling operations are not interrupted during retrieval of a pod whose apparatus for controlling the subsea drilling operations has failed; and methods with such a system for retrieving a subsea pod from a lower marine riser package platform.

Abstract: An underwater well system in which an initially vertical drilling riser conduit (5A) is fixed by a template at the seabed in a non-vertical orientation. Drilling is carried out through wellhead in the template which also includes a valve tree allowing the production fluid to be brought to the surface along a line separate from the drilling riser conduit. The template may be a junction template allowing several wells to be drilled from a single template, or allowing the template to be connected by one or more drilling conduits to further templates such that a wide area of the seabed can be covered for a single drilling riser conduit.

Abstract: An apparatus for pointing twist drill bits includes a processing unit which has a rotary index plate on which are mounted a plurality, e.g., five, of drill bit holders which are circumferentially spaced apart at equal, e.g., 72-degree intervals, and a loading unit which has located adjacent to the index plate a rotary pedestal on which are mounted an equal number of transfer arms. Located around the periphery of the processing unit and loading unit are a plurality of processing stations and loading unit operation stations, respectively.

Abstract: A semisubmersible multipurpose unit (MPU) having a deck, a multipurpose tower secured to the deck, supports, pontoons connected to the supports with each pontoon adapted for ballast transfer, at least two hawsers connected to the MPU for connecting the MPU to an object at sea having a mooring system, a hawser guidance system to direct each hawser to the object at sea, a crane secured to the deck of a semisubmersible MPU, and at least an 6-point mooring system, wherein the combination of the semisubmersible MPU, hawsers and 6-point mooring system create a global equilibrium between the mooring system of an object at sea and the at least 6-point mooring system and the hawsers have both an elasticity sufficient to accommodate the wave frequency between the object at sea and the MPU and a stiffness adequate to synchronize the average and low frequency movements during a 10-year storm.

Abstract: A self-elevating drilling unit has dual cantilever assemblies that move longitudinally and transversely in relation to the jack-up platform to allow drilling operation to be performed from two drilling floors. The twin cantilever assemblies permit simultaneous drilling on an 8 feet×8 feet spacing. The cantilever assemblies are retained attached to the platform by a hold down beam that extends over and across the cantilever assemblies. The hold down beam is positioned in a stationary manner on the platform deck. A movable strut that engages the underside of the hold down beam moves along the beam to counteract upward bending forces acting on the beam when the cantilever assemblies are extended from the platform. The cantilever assemblies are made of tubular truss work and can be moved to an infinite number of horizontal positions.

Abstract: A method of conducting operations to an offshore field from multiple separated drill centers using a floating vessel having a turret-mounted mooring element and a workstation separate from the mooring element in which the vessel is moored at a central mooring element location and operations are sequentially carried out at separate drill centers associated with the mooring element location by allowing the vessel to weathervane to a heading associated with a subsequent drill center once operations have been completed at a first drill center.

Abstract: A surface vessel is anchored almost geostationarily by a turret rotatable relative to the vessel about a vertical axis and having mooring cables extending to the seabed. A well is drilled from a drilling section in the vessel at a distance from the axis of rotation of the turret. The drilling is performed using a drill string through a riser extending from the seabed to the drilling section, which riser can be broken and shut off between the seabed and the vessel. By manipulating (hauling in and slackening) the mooring cables, the vessel is held in position so that the derrick is kept almost geostationary relative to the well during drilling operations. The system includes a surface vessel, a turret rotatable relative to the vessel about a vertical axis and which can be anchored to the seabed by a plurality of mooring cables, and a riser extending from the seabed to the vessel through which the well can be drilled with a drill string from a derrick in a drilling section on board the vessel.

Abstract: A method is disclosed for controlling pressure in a wellbore during drilling. The method includes operating a drilling system to have a first fluid pressure gradient inside a drillstring extending from the earth's surface to a drill bit at the bottom of the wellbore. The drilling system has a second fluid pressure gradient lower than the first fluid pressure gradient in an annular space between the drillstring and the wellbore from a selected depth in the wellbore to the earth's surface. Introduction of drilling fluid to the inside of the drillstring is stopped, and fluid flow in the annular space from a point below the selected depth to a point above the selected depth is selectively controlled to cause a substantially constant fluid pressure at a predetermined depth in the wellbore.

Abstract: A dual riser assembly for use with an offshore multi-activity drilling assembly to conduct drilling operations from a deck above the surface of a body of water into the bed of the body of water utilizing two risers, a first and a second, which extend from a location above the surface of a body of water to a common location adjacent to the bed of the body of water. Each riser terminates, at a distal end, into a dual riser assembly, allowing for selective open internal communication between each of the two risers and a single wellhole.

Abstract: A wellhead assembly has an inner wellhead that lands in an outer wellhead, the inner wellhead having first and second internal passages. Each passage has an upper opening at the outer surface of the inner housing and a lower opening at the inner surface. An external shoulder of a casing hanger lands on an internal shoulder of the inner housing, the lower opening of the first passage being below the internal shoulder, the lower opening of the second passage being above the internal shoulder. The casing hanger has a substantially-vertical passage located in its sidewall, an upper port registering with the lower opening of the second passage, a lower port being located below the external shoulder for communicating with the annulus. Valve assemblies at the upper openings control the flow of heavy fluid injected into a casing annulus through the second passage and of cuttings injected into the annulus through the first passage.

Abstract: An apparatus, system and method of manufacturing a marine riser constructed of an aluminum alloy having a high strength-to-weight ratio is provided. The inventive riser apparatus comprises a plurality of riser sections coupled serially end-to-end, wherein each of the riser sections comprises a pipe having a first end and a second end, a first flanged coupling welded to the first end of the pipe, and a second flanged coupling welded to the second end of the pipe, wherein the pipe is constructed of an aluminum alloy having a strength-to-weight ratio greater than that of steel. The riser apparatus may optionally include one or more auxiliary lines providing hydraulic communication with a blowout preventer.

Abstract: A tubing handling for subsea oilfield tubing operations, includes an isolation tube to mechanically and/or chemically protect the drill string and improved passage of the drill string and fluid return line to the drilling vessel that further protects them during drilling use. In addition, the improvements include an automatic safety apparatus to hold against unintended movement of the tubular members under extreme length and weight conditions as well as against human error at the rig. Further, the invention includes multi-segment coiled tubing drill strings that can be adapted to drilling requirements in a deep wellbore.

Abstract: A drilling and production template for sub-sea wells comprises a plurality of individual limbs (1-4) each with a central hub (10-14) at one end of an arm (11-41) and a drilling receptable (12-42) on the other end of the arm. The hubs are of different diameters such that they fit within each other in a telescopic manner. They have cut-out (27, 37, 47) accommodate the arms of the other limbs when installed. The template may be deployed onto a pre-installed foundation with the arms stacked vertically above the other, in such manner as to pass through the moonpool of a drilling vessel. The complete assemblies are installed on a mechanical running tool attached to a drilling string. After the template is disposed on the foundation, the drilling string is rotated, causing the running tool to rotate the limbs (1-4) so that the hubs telescope into each other, providing a splayed multi-well drilling and production template.