Abstract: Method and assembly for conducting wireline operations in a deep, subsea location. The method includes providing a rig on the surface of a body of water, having a riser extending from the rig floor to the sea floor; an annular preventer positioned on the end of the riser on the sea floor; a plurality of blowout presenters positioned below the riser to prevent a blowout into the riser; and, a wireline subsea blowout preventer control head. A lubricator is lowered into the riser, with the control head attached thereto, and wherein the wireline tool is disposed within the control head. The lubricator is position within the annular preventer. Wireline operations may then be conducted. If a blowout occurs during wireline operations, any pressure would be prevented from entering the riser, and would be contained by the control head.

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: 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: A riser recoil control system (10) adjusts tension forces (F1, F2) applied to a marine riser (60), which is attached to an anchored, floating vessel (30) and a wellhead (80). The riser (60) is attached to the vessel (30) using tension forces (F1, F2) asserted by riser tensioners (20). Each tensioner (20) has an air shutoff valve (110), and an orifice-controlled fluid valve (120). A disconnection sensing means (200) provides a disconnect signal when the riser (60) is disconnected from the wellhead (80), which closes the valves (110, 120) and adjusts the tension forces (F1, F2) applied by the tensioners (20). The invention includes a method for adjusting the tension forces (F1, F2) applied to the riser (60), including sensing the disconnect signal and adjusting the tension forces (F1, F2) supplied to the riser (60) by closing the air shutoff valves (110) and partially closing the orifice-controlled fluid valves (120).

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 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: Methods for moving drilled cuttings, the methods, in certain aspects, including conveying with air under positive pressure, drilled cuttings to flow conduit apparatus; applying air under positive pressure to the flow conduit apparatus to continuously move the drilled cuttings material therethrough; continuously moving the drilled cuttings material with the air under pressure to separation apparatus; with the separation apparatus continuously separating drilled cuttings from air; wherein, in certain aspects, the drilled cuttings are included in a low density slurry with drilling fluid, drilling mud, and/or oil and wherein, in certain aspects, the separation apparatus is a cyclone separator and the drilled cuttings moved into the cyclone separator are wet; and systems for effecting such methods.

Abstract: A vessel includes a riser and/or tendon tensioning construction. A connector, such as an arm or deck structure, is suspended from cables movable relative to cable guides. The connector carries two or more risers and/or tendons extending from a subsea structure to above water level. The free ends of the cables are attached to weights for exerting a tensioning force on the risers, which are substantially decoupled from pitch, roll and heave motions of the vessel.

Abstract: Platform for drilling after or production of hydrocarbons at sea, consisting of a semi-submersible platform body (2) which supports drilling and/or production equipment on its upper surface. The platform body (2) is designed as a vertical mainly flat bottomed cylinder which is provided with at least one peripheral circular cut-out (5, 30, 35, 36) in the lower section of the cylinder since the centre of buoyancy for the submerged section of the platform (1) is positioned lower than the centre of gravity of the platform.

Abstract: A drilling rig having a deck capable of being used offshore and a method for commissioning a well using the drilling rig and a method for decommissioning a well using the drilling rig, wherein the drilling rig comprises: a cantilever which is mounted so as to be moveable in a first direction and a second direction; a Multi Purpose Tower mounted on the cantilever; a supporting cart disposed between the cantilever and the deck which in turn is movably fixed on the deck of the drilling rig; at least two friction reducing devices attached to the supporting cart; and wherein the cantilever can slide relative to the drilling platform.

Abstract: An arrangement for transferring loads by means of one or more hydraulic cylinder-like actuators (19, 26, 40) in order to establish and maintain tension in a riser (1) of the type typically used in offshore petroleum production, where the riser (1) constitutes a connection between the sea bed (2) and an installation (4) on or near the surface of the sea (6), and where the required pressure difference between the pressure side(s) (18, 42) and the depressurised side(s) (17, 46) of the actuator(s) (19, 29, 40) is constituted by a hydrostatic pressure difference.

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: A floating drilling rig configured for performing drilling operations while floating on a body of water is modified to become a converted vessel configured for performing drilling operations while resting on bottom by attaching a support barge component adapted to add rest-on-bottom functionality. The support barge component has a ballast system that alone or by supplementing the ballast system of the floating drilling vessel enables the floating drilling vessel to be ballasted to rest on bottom. The ballast system of the support barge component is adapted to be opened to the water to fill and drain as the water level raises and lowers, and thereby maintain a constant soil pressure. The support barge component may also have a suction breaker system to break suction formed between the support barge and bottom.

Abstract: A method and a system are described for processing of drilling fluid from a drilling hole (10) in an underwater well to a floating drilling rig or drilling vessel, comprising a sealing device (12) connected to a well head, a pump module (14) to transport drilling fluid, a treatment plant for treatment of drilling fluid, or a storage installation. Before a blow-out valve is connected to the well head and before a riser is connected between the drilling hole and the floating drilling rig or drilling vessel, the pump module (14) placed on the ocean bed transports drilling fluid from the drilling hold (10) on the ocean bed to the floating drilling rig or drilling vessel.

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: A system for drilling wells includes a plurality of platform modules, which are interconnected to one another on site to form a unitary platform structure. The interconnected platform modules are elevated above a surface on plurality of legs coupled to at least some of the platform modules. The elevated interconnected platform modules support drilling and auxiliary equipment. The system is well adapted for use in arctic, inaccessible, shallow water or environmentally sensitive locations.

Abstract: A system 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 offshore and land-based drilling applications is disclosed. The present invention combines a base fluid of lesser/greater density than the drilling fluid required at the drill bit to drill the well to produce a combination return mud in the riser. By combining the appropriate quantities of drilling mud with a light fluid, a riser mud density at or near the density of seawater may be achieved to facilitate transporting the return mud to the surface. Alternatively, by injecting the appropriate quantities of heavy fluid into a light return mud, the column of return mud may be sufficiently weighted to protect the wellhead. At the surface, the combination return mud is passed through a treatment system to cleanse the mud of drill cuttings and to separate the drilling fluid from the base fluid.

Abstract: A Jack Up drilling rig having a deck capable of being used offshore made of a cantilever which is mounted so as to be moveable in a first direction and a second direction, a Multi Purpose Tower fixably mounted on the cantilever, a supporting cart disposed between the cantilever and the deck of the Jack Up drilling rig, and at least four friction reducing devices, wherein the Jack-Up drilling rig is also used in methods for installing and decommissioning drilling equipment on a sub-sea well.

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: A method for assembling and delivering a drivepipe to a drill site. The method has the following steps: The drivepipe is assembled at a shoreline assembly station. Floatation devices are attached to the drivepipe and the drivepipe is floated in the ocean. The drivepipe is towed with tow vessels to a drill site. The drivepipe is delivered in a horizontal orientation to a drilling vessel at the drill site. An upper end of the drivepipe is attached to the drilling vessel and the tow vessels are detached from the drivepipe. The drivepipe is pivoted about its point of attachment to the drilling vessel until the drivepipe is vertically oriented. The buoyancy function of the floatation devices attached to the drivepipe is deactivated. The floatation devices are removed from the drivepipe. The drivepipe is equipped with a driving mechanism and the drivepipe is lowered with a running string from the drilling vessel to the sea bed.

Abstract: Improved method for the drilling of the initial phase of deep water oil wells with an underwater well head consisting in the positioning and cementation of the conductor pipe and anchorage casing by means of a single drilling phase. A tapered hole (with a double diameter) is drilled using a drill string consisting of a motor driven pilot bit and a reaming bit.

Abstract: A floating offshore platform configuration is provided, which decouples pitch, roll, and heave motions from acting on tensioned risers and accommodates the angular displacement induced by floating offshore platform surge and/or sway excursion without inducing bending in the riser at its entrance to the floating offshore platform. The risers are guided by an inner structure that is tethered from the sea floor and centered inside an outer hull structure. Outer hull structure heave, pitch and roll motions are substantially isolated from acting on the inner structure through a connection mechanism, and each riser is allowed to individually expand or contract.

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: The present invention provides a method for drilling, analyzing, and stabilizing subsurface formations. The system is generally formed around a reusable bottomhole assembly (BHA) that provides an anchoring and thrust mechanism, furnishing the necessary downward force needed to provide comminution of geological material in a borehole. The BHA is conveyed into the borehole via a communications link wireline equiped with internal power and data telemetry lines. The BHA permits the use of multiple comminution sampling and analysis tools via a coupling device. The BHA and communications link wireline are mounted so as to couple with different tools. The main drilling mechanism is a torque drive assembly powered coring tool. A borehole televiewer and/or logging analysis tool may follow each coring period. The final step in each coring period is a wellbore consolidation technique. This series of steps is then repeated, each time coring the wellbore to a deeper depth.

Abstract: A method and apparatus for controlling the riser base pressure and detecting well control problems, such as kicks or lost circulation, during drilling of an offshore well using a gas-lifted riser. The pressure control apparatus preferably includes two separate control elements, one to adjust the pressure at the surface (prs) and the mass flow rate out of the top of the riser ({dot over (m)}o) to compensate for changes in riser base pressure (prb) and the other to adjust either or both of the boost mud flow rate (qb) and lift gas flow rate (qg) to maintain a constant or nearly constant mass flow rate entering the base of the riser ({dot over (m)}i). According to the method of the present invention, the well return flow rate (qw) is preferably determined by directly measuring various other parameters and then computing qw from the measured parameters. The computed value of qw may be compared to the drill string flow rate (qc) to detect well control problems, such as kicks or lost circulation.

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 system for drilling wells includes a plurality of platform modules, which are interconnected to one another on site to form a unitary platform structure. The interconnected platform modules are elevated above a surface on plurality of legs coupled to at least some of the platform modules. The elevated interconnected platform modules support drilling and auxiliary equipment. The system is well adapted for use in arctic, inaccessible, shallow water or environmentally sensitive locations.

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: A method of drilling an offshore underwater well comprising the steps of installing a riser conduit so that it is substantially vertically supported at a production deck. The riser conduit deviates progressively further from the vertical with increasing sea depth, so that its end can be anchored at the seabed by a skid either at an oblique angle so that drilling into the seabed can be carried out at the oblique angle, or horizontally, so that the riser conduit can extend some considerable distance across the seabed before drilling is carried out.

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: An improved method and apparatus for removing proppant from fluid used in an oil and gas well for reuse in future operations. The proppant is separated from the well fluid and transported to a materials collection tank. A crane then transports the materials collection tank onto a processing boat. On the processing boat, the proppant is vacuumed from the materials collection tank to a hopper. The proppant is then discharged from the hopper into a holding tank for treatment and reuse. In a first alternative embodiment, two hoppers are positioned above each other so that the proppant can be added to the upper hopper and then fed by gravity to the lower hopper. A valving arrangement maintains vacuum within the interior of at least one hopper at all times to provide a continuous vacuum operation. A conduit discharges from the lower hopper into the holding tank.

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 multi-gradient system for drilling a well bore from a surface location into a seabed includes an injector for injecting buoyant substantially incompressible articles into a column of drilling fluid associated with the well bore. Preferably, the substantially incompressible articles comprises hollow substantially spherical bodies.

Abstract: The drilling vessel includes at least one floating body and a platform which is supported by one or more support columns on the floating body and includes a drilling installation. The vessel is provided with storage provisions for tubular drilling equipment. The storage provisions include one or more shafts which are disposed in one or more of the support columns, extend downwards from the platform and in which a number of items of the drilling equipment can be vertically disposed.

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 vessel includes a riser and/or tendon tensioning construction. A connector, such as an arm or deck structure, is suspended from pivot arms on the vessel. The connector carries two or more risers and/or tendons extending from a subsea structure to above water level. The free end of the pivot arms is attached to a weight for exerting a tensioning force on the riser which is substantially decoupled from pitch, roll and heave motions of the vessel.

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: A subsea well intervention vessel comprising a dynamically positionable tanker and direct well intervention equipment mounted on a deck of the tanker. The direct well intervention equipment may be 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 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 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: An apparatus and method are provided for controlling hydrostatic pressure in drilling fluid in a subsea well. A main pump forces drilling fluid down the drill pipe, out of the end of the drill pipe, and upward in an annulus surrounding the pipe. A rotating drilling head is attached to a wellhead assembly at the sea floor. The drilling head has an inner body rotatably carried in an outer body landed in a bore of a housing. An energizable gripper in a bore of the inner body grips an outer surface of the drill pipe. The drilling head diverts the drilling fluid into a lateral passage in the sidewall of the housing. An auxiliary pump forces seawater through a venturi into a conduit, creating a lower pressure to draw drilling fluid into the conduit to be carried back to the surface vessel. Pressure and flow rate measurements are sent to a control system that modulates the speed of each pump to control hydrostatic pressure.

Abstract: A drilling riser for use at great sea depths for drilling of wells in the seabed using a drill string, with the drilling riser arranged to be connected between a wellhead at the seabed and a vessel, and arranged for use with a drilling fluid with sufficiently high density to balance the fluid pressure from the geological formations, with a sensor arranged to detect the level of the drilling fluid's level in the drilling riser, and a return riser pipe with an adjustable return riser pump. The return riser pipe extends up to the vessel, from an outlet on the riser, from a depth which is substantially below the sea surface, and at the same time at a height substantially above the seabed.

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: A method for drilling a well below a body of water as disclosed which includes injecting into the well, at a depth below the water surface, a liquid having a lower density than a density of a drilling mud producing a mixture of drilling mud and low-density liquid in the well. The mixture of drilling mud and low-density liquid is withdrawn from an upper end of the well. The drilling mud and the low-density liquid are separated, with at least a portion of the separated low-density liquid returned to the depth below the water surface and at least a portion of the separated drilling mud returned to an upper end of the drill string.

Abstract: A drill cuttings injection system injects cuttings from drilling a well into a wellhead assembly. The wellhead assembly has a tubular housing mounted to an upper end of a well and a casing hanger concentrically located in the housing, defining an annular clearance. A port extends through the housing for injecting a stream of drill cuttings into the annular clearance. A sleeve is mounted in the port. The sleeve has a cylindrical sidewall and an inner end containing a deflection plate. The sleeve has an aperture in the sidewall adjacent the deflection plate for discharging the stream after the stream contacts the deflection plate. The deflection plate protects the casing hanger from erosive contact with the stream.

Abstract: Method of, and apparatus for, sinking bore holes, in particular exploratory and extraction bore holes, in the sea bed (40). The material from the sea bed is loosened with the aid of a rotating drill head (10) which is arranged at the bottom end of a drill string (5) which is suitable for transmitting a torque. The top end of the drill string is mounted on a floating platform (1), it being the case that the drill string (5) comprises at least two telescopically interengaging drill-string parts (6, 7) which, during a vertical movement of the platform, induced for example by the sea swell, execute a movement relative to one another, with the result that the drill head (10) rests with an essentially constant force on the surface which is to be cleared away.