Abstract: There is disclosed an apparatus for use in drilling an offshore well wherein the upper end of a riser is intermittently supported from a floating vessel to permit the lower ends of additional pipe sections to be connected thereto and then lowered through the table for connection at its lower end to an underwater wellhead. The riser is supported from the vessel in such a manner as to absorb the load of the riser as an additional section is landed on its upper end, and then carry the load of the riser as the vessel tilts or rolls without imposing undue bending loads on the riser.

Abstract: A passive tensioner is described for accommodating the tensile loading between a floating oil production platform and a riser. The tensioner includes a stack of strut elements, each of which has a plurality of struts of an elastomeric material individually configured to respond to a compressive load by buckling in a predetermined direction, means for constraining the stack during such buckling in a direction generally orthogonal to the direction of the compressive load and means for translating the tensile loading because of ocean wave, current or other liquid action on the platform into a compressive load and applying the same to the stack.

Abstract: A subsea wellhead tieback connector actuated solely by axial motion to achieve connection to and disconnection from the wellhead. The connector includes interconnected inner and outer bodies, a split lock ring surrounding the inner body, and an energizing mandrel for non-rotary axial movement to expand the lock ring into engagement with a wellhead component.

Abstract: A method for drilling offshore wells in deep water with greater safety and with fewer casing strings, maintaining a maximum diameter wellbore in the early stages of drilling to facilitate casing operations in and beyond deviated sections, and providing full well control while setting surface casing. This method utilizes a two-riser system for drilling in which the surface casing interval is run and set within a large diameter, light duty riser. Thereafter, drilling proceeds with a heavy duty riser.

Abstract: A concentric riser parallel bore subsea well assembly for controlling production from a subsea wellhead to a floating production facility. The invention utilizes a concentric riser and tubing string in combination with a dual parallel bore production tree. The production tree communicates with a parallel bore tubing hanger that communicates with the production tubing string and the casing annulus.

Abstract: The improved structure of the present invention is provided to utilize the drilling riser tension ring and rig tensioning to tension a completion riser. A tension sleeve is provide which is secured to the upper end of the completion riser and is designed to have a diameter sufficiently small to allow it to pass through the spider in the rotary table. An adapter tension ring is also provided which is secured to the drilling riser tension ring and has a design allowing the tension sleeve to pass therethrough and be secured therein so that raising the sleeve may raise the adapter tension ring and tension exerted on the drilling riser tension ring or the adapter tension ring may be utilized in tensioning the completion riser.

Abstract: Riser clamps are installed onto fixed or compliant offshore platforms by a diverless technique. Each riser clamp is rigidly or hingedly attached to a heavy tapered wedge. Mating tapered receptacles are built into the platform, preferably at various levels along a corner leg. Only one lift line is utilized which may be either a drill string or wire rope, and one remotely operated vehicle (ROV) for observation, to lower and stab each riser clamp into one of the tapered receptacles on the platform.

Abstract: A hydraulic control umbilical is disclosed for supporting a plurality of hydraulic control lines along a riser between a surface facility and a subsea completion. The umbilical provides a skin encircling the riser substantially its entire length with means for supporting the skin about the riser and means for supporting the hydraulic control lines within the skin. A method for deploying and retrieving the hydraulic control umbilical is also disclosed.

Abstract: A swivel-less coupling suitable for producing oil from an underwater well through a riser to a floating vessel or for transferring fluids to or from such a vessel is formed of an inner drum and a surrounding annular surface. The surface carries one or more flexible pipes which can wind and unwind helically across it to accommodate limited relative rotation as between the inner end(s) of the pipe(s) which is fixed to the drum and the outer end(s) and the pipe(s) which is fixed at a point which is rotatable relative to the drum. The pipe or pipes may be carried on cradles which can move across the surface. Relative movement as between the inner and outer ends of the pipe may be regulated by a motor, which may be controlled by sensors noting any tendency for change in the relative positions due to forces acting on the vessel.

Abstract: Disclosed is a method for disconnecting a marine riser assembly from a subsea wellhead when the marine riser assembly contains substantially gas, the marine riser assembly comprising a riser and a wellhead connector having an internal shoulder for abutting against the top of the subsea wellhead. The method comprises equalizing the pressure acting on the internal shoulder of the wellhead connector and the seawater pressure acting external to the wellhead connector.

Abstract: There are disclosed several embodiments of a marine riser having means for disrupting smooth flow of seawater along its length of the riser and thus damping vertical oscillation of the riser when its lower end is released from a subsea wellhead.

Abstract: Apparatus for performing drilling operations and for servicing an underwater well from a surface installation comprises a main string that is removable from the top of the wellhead in a way that is totally independent of auxiliary hoses which are hoses suspended from the surface installation independently of the main string and at a distance from it, from separate elements making possible the continuous advance of the hoses. The length of the hoses is adjusted in service so that they form, in the water, a plurality of catenaries supported by the surface installation and connected to the top of the wellhead with interposition of curvature-limiting elements.

Abstract: A guidelineless reentry system for a subsea well uses a downward facing funnel. The well has a mandrel surrounded by a guide frame. A funnel and a mandrel connector are carried by the riser. Retracting rollers are mounted to the funnel. Once the riser lands on the guide frame, the rollers are extended to latch the funnel to the guide frame. The funnel is rotated along with the riser to orient the mandrel connector. The mandrel connector is lowered relative to the funnel into engagement with the mandrel.

Abstract: A guidelineless reentry system for a subsea well uses a downward facing funnel. A guide ring is mounted to the guide frame, which in turn is mounted around a mandrel on the well. A funnel and a mandrel connector are carried by the riser. Once the riser lands on the guide ring, latches are actuated to connect the funnel to the guide ring. Then, the mandrel connector is lowered relative to the funnel into engagement with the mandrel. A cam moves dogs outward to engage grooves of the mandrel to lock the mandrel connector to the mandrel.

Abstract: A guidelineless reentry system for a subsea well uses a downward facing funnel. The well has a mandrel surrounded by a guide frame. A guide ring is mounted to the guide frame. A funnel and a mandrel connector are carried by the riser. Rollers mounted to the funnel engage the guide ring to allow the mandrel connector and funnel to be rotated to orient the mandrel connector. Once the orientation is achieved, the mandrel connector is lowered relative to the funnel into engagement with the mandrel. A cam moves dogs outward to engage grooves of the mandrel. The mandrel protrudes upward from the guide ring.

Abstract: Subsea template and method for using the same. A subsea template includes a plurality of gimballed joints for receiving piles therethrough which are anchored in the sea floor. Also included are a plurality of gimballed joints for receiving well conductors therethrough. A template is lowered to the sea floor. The piles and well casings are inserted into their associated gimballed joints from a substantially vertical axis and when finally positioned, are fixedly connected to the gimballed joint associated therewith thus obviating the need for leveling the template.

Abstract: A floating drilling platform having dual work stations is disclosed for performing deep sea drilling and/or hydrocarbon production operations. The structure of the platform is designed to accommodate replaceable modules which facilitate the installation and removal of either a drilling derrick or production equipment. Thus, during the drilling phase of a reservoir's development, the platform may be outfitted with dual drilling derricks while at later times the platform may be outfitted with a drilling derrick and a full production facility. Various expedients are available to permit the equipment of one work station to be used in conjunction with the equipment of one other. Simultaneous management of dual conductors is enabled by a dual riser management system which models in real time riser behavior under varying environmental and other operational conditions. The dual riser management system includes a riser analysis subsystem, a mooring analysis subsystem and a vessel stability analysis subsystem.

Abstract: An improved riser for a multiple bore subsea well providing wireline access to each of the bores through a single opening at the upper end of the riser and including an upper tubular member having a single bore, a tubular housing surrounding the lower portion of said upper tubular member, bearing means within said tubular housing for supporting rotation of said upper tubular member with respect to said tubular housing, a lower housing member having multiple bores which mate with the multiple bores of the tubing hanger running tool or the christmas tree running tool, said upper tubular member having an offset portion within said tubular housing which, when rotated can align with the opening of the upper end of the bores through said lower housing member, means securing the lower end of said tubular housing to said lower housing member, a skirt connected to said upper tubular member within said tubular housing and extending into sealing engagement with said lower housing member and being in surrounding relation

Abstract: A device for connecting lines associated with offshore drilling equipment comprises at least one support (24, 24') hinged to the platform by tie rods (25, 25') and movable between a position of withdrawal away from the drilling column and an operating position, near the drilling column, enabling the lines (19, 20) to be connected. A jack (35, 35') enables the support (24, 24') to be moved. In the operating position, the upper sections of the lines (19, 20) carried by the telescopic joint (2) of the drilling column have their joining members (17, 18, 21) located in concordance with the joining pieces (31) of the end parts (30) of the lines connected to the platform.

Abstract: A system and method for servicing subsea wells with a flexible riser. The flexible riser can be modified for use either with wireline or through the flow line tools. The flexible riser eliminates the requirement for motion or heave compensating equipment associated with rigid marine riser systems. The flexible riser, lower riser package and associated surface support equipment can be used to obtain vertical access to a subsea well without the need to use a drill ship or semisubmersible.

Abstract: An upper marine riser package (10/10A) comprising a diverter (D) for diverting uncontrolled gas and return drilling mud therethrough, a flexible joint FJ for allowing tilting motion between a vessel and a riser string (RS), a self-tensioning slip joint (SJ) and riser rotation bearing joint (RB) suspended below said vessel (V) to compensate for vertical motion between a subsea well (W) and a floating vessel (V). The upper marine riser package (10/10A) is sized to be run through a confined opening such as a riser handling spider (HS) and rotary table (RT) and to be suspended and operated below the deck of the vessel (V). The upper marine riser package can be used to eliminate the conventional riser tensioners normally above the platform and can be used in combination with such conventional riser tensioners normally above the platform for deeper and deeper drilling opertion.

Abstract: An apparatus and method useful in offshore well drilling operations for cleaning the annular space between mudline suspension risers during and after cementing operations to assure that riser backout may be accomplished if a temporary abandonment of a well is to take place. A two-section drive pipe having a quick stab connector between the upper and lower sections of the pipe is provided with ports around the periphery of the lower section and above the mudline. Circulation of fluid down high pressure hoses connected to these ports and up the annulus between the drive pipe and well conductor string within the drive pipe is established using rig pumps located on the deck of the rig. Simultaneously, cement slurry is pumped down the well conductor string to the bottom of the well and up the annulus between the drive pipe and well conductor string.

Abstract: An apparatus for connecting a riser to a wellhead housing for a tie-back connection allows connection without rotation or hydraulic actuation. A connector body is mounted to the lower end of the riser for lowering over the wellhead housing. Dogs are carried in the connector body, each having grooves on its interior for mating with grooves formed on the wellhead housing. Guide surfaces in the connector body allow the dogs to retract and extend, but only in directions perpendicular to the upper flanks of the wellhead housing grooves. Springs urge the dogs inwardly and downwardly to lock the connector body to the wellhead housing. A release mechanism allows the connector body to be pulled upwardly and removed from the wellhead housing.

Abstract: An off-shore floating oil production system is provided with an improved riser support.The oil production system comprises a floating vessel 2 having a moonpool 3 and a support system for supporting a riser 16 running through the moonpool 3. The support system comprises guides 7 in the moonpool 3, a carriage 6 which runs on the guides 7 and means 11 for supporting the carriage 6 which contains a pivoted support (12,13) for the riser 16. Means 17 are also provided for permitting rotation between a section of the riser 16 and the carriage 6.Vertical movement of the carriage compensates for heaving of the vessel, movement of the pivoted support for pitching and rolling and movement of the rotatable means for "weathervaning".

Abstract: A tie-back connector for a subsea well allows the tie-back connection to be made without rotation. A set of threads is located on an inner wall of the outer conduit into which the tie-back connection is to be made. An annular latch is carried by the inner conduit which is being tied back from the surface to the outer conduit. The latch has threads on its exterior which ratchet past the threads on the inner wall as the inner conduit is lowered into the outer conduit. After the threads of the latch are ratcheted fully into alignment with the threads in the outer conduit, the inner conduit is pulled upwardly relative to the latch to secure it in tension. A retainer is actuated when the inner conduit is in the upper position to prevent the inner conduit from moving downwardly again relative to the latch. The inner conduit can be removed by rotation relative to the outer conduit.

Abstract: A watertight compartment at a floating production plant handing crude oil and/or gas has at least one remotely releasable two-part connecting piece for a riser conduit between the sea floor and the plant. The compartment includes a sealing collar mounted in the bottom plating of the plant. The collar provides a sealing with respect to an upper half of the connection piece in relation to the compartment, as well as with a lower half of the connection piece, which is surrounded by water.

Abstract: There is disclosed a type of riser to connect subsea hydrocarbon production equipment to a floating storage, process or control facility which combines the advantages of integral and non-integral risers previously used. This is achieved by a locking mechanism which allows the individual tubes to be freed once each section of riser is added, and a subsea remotely operated connector that allows individual tubing to be released. Improvements in the design of collet connectors are also disclosed. There is also disclosed a guidelineless method of connecting risers or other equipment to subsea installations. The method uses a cone on the subsea equipment and a guideframe on the riser. The guideframe aligns itself with the subsea cone prior to the riser being connected. As the riser is drawn to the subsea mandrel the guideframe aligns the riser connector with the mandrel. A still further embodiment disclosed herein is a flexjoint consisting of a series of flexjoints in an outer case with a high pressure tube inside.

Abstract: In an arrangement including remotely releasable couplings for riser conduits between the sea floor and a floating plant processing crude oil and/or gas, the couplings are located in at least one chamber below the water line of the plant. This chamber is closed towards the atmosphere and provided with at least one downwardly directed opening communicating with the surrounding water. Structure is provided for governing the air pressure in the chamber, which is accessible through an air lock.

Abstract: A circular guide table is provided for a marine production riser comprising an opening for the central tube having a ball joint allowing angular movement of the tube in any direction with respect to the table and two radial arms offset from each other by an angle close to 90.degree. fixed to the table and whose ends each support a sliding device, such as a roller carriage capable of sliding along vertical rails fixed to the platform. The table is formed from an inner collar in the form of a hub to which are fixed spokes between which the peripheral production stringers pass, the opposite ends of the spokes being joined together by an external collar provided with radial arms.

Abstract: A method and means for storing a marine riser is disclosed for relocating an offshore mobile unit from a drilling or production site. The riser is disconnected from a subsea port and lowered into an auxiliary borehole. Means are provided for the lowering and raising of the marine riser and positioning of same.

Abstract: A system is provided for guiding the central tube connector of a production riser for positioning same on an underwater well head installation. The central tube carries, during lowering, a support integral with the tube and formed by a horizontal plate having on its periphery a truncated cone shaped collar widening out towards the bottom, a guide funnel which freely rests on said support having a shoulder also widening out towards the bottom. The tube is lowered until said funnel is engaged on the installation head then, continuing the descent, the tube no longer supports the weight of the funnel and the connection may take place in a conventional way.

Abstract: A marine heave compensating device comprises a hydraulic piston and cylinder unit (15,16) with its cylinder (15) secured to a support (10,11). The piston is connected via a piston rod (16) to a cross-head (17) on which a first set of pulleys (18) are rotatably mounted. Chains (19) secured at one end to the support (10,11) are entrained around pulleys (18) and support a yoke (20) on which is mounted a crown block (21). A cable (22) is reeved around crown block (21) and around a travelling block (23) which carries a tool carrier (24). The two ends of cable (22) are reeved around two second pulleys (26A,26B) rotatably mounted on the cross-head (17). End (22A) of cable (22) is connected to a draw-works and end (22B) of cable (22) is connected to a tie-down.

Abstract: Method and apparatus for use in drilling a well from a floating vessel by means of a riser, which connects the vessels drilling equipment to a wellhead assembly adjacent the ocean floor. The riser is capable of being disconnected from the wellhead assembly, and having its upper end locked to the vessel. The present riser locking apparatus is made up of selectively-positionable resiliently-moveable locking beams adapted to be remotely actuated to lock the upper elements of the riser to the vessel, thereby preventing lateral or vertical movement of the riser relative to the vessel.

Abstract: Production from a subsea wellhead to a floating production facility may be realized with the use of a substantially neutrally buoyant flexible production riser which includes biasing means for shaping the riser in an oriented broad arc. The broad arc configuration permits the use of wireline well service tools through the riser system.

Abstract: A support and connection system for a riser run from a subsea well to a floating vessel has a female housing supported from the vessel that receives a male termination head secured to the riser string. The termination head fits within a tapered bore in the termination housing. Radial ports connect with radial passages in the termination head for transmitting fluids to and from the vessel and subsea well. A compound curved seat prevents jamming of the termination housing in the termination head due to the high tension placed on the termination housing. The seat is annular and also curves in a vertical direction.

Abstract: This invention concerns the connection and disconnection of well-pipes in an articulated structure level with the articulation.The device comprises a length of flexible pipe, at one end of which is an adapter containing a sealing device, a positioning device and a locking device, and at the other end of which is another adapter containing a sealing device and a locking device, these sealing, positioning and locking devices being designed to fit into upper and lower receptacles, the upper receptacle consisting of the lower end of the tubing pipe, and the lower receptacle consisting of the upper end of the seabed pipe, the whole connection-disconnection device being able to pass through the upper receptacle.This connection-disconnection device is specially designed for use in articulated hydrocarbon-production installations.

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

Abstract: A buoyancy assembly for mounting on a pipe such as a marine riser having service lines, such as choke and kill lines extending therealong, the assembly including discontinuous clamping band members shaped to encompass the pipe and having brackets disposed to join the ends of the band members and tighten their grip on the pipe when bolts joining the band members to the brackets are tightened, the brackets having opposed walls extending outwardly therefrom and supporting cradles to receive and clamp the service lines, and the assembly including arcuate flotation modules of syntactic foam shaped to lie against the riser pipe and removably occupy the spaces between the service lines and form a generally cylindrical outer contour, the modules being held in place against the pipe by tensioning belts each comprising a strap anchored to the adjacent brackets and being tensioned by a tension bar gripping an end of a strap and bolted by tensioning bolts to a link which is pivotally connected to the adjacent bracket.

Abstract: An improved system for anchoring a floating vessel which is anchored only by parallel and essentially vertical conduits. The anchoring load is carried by units of concentric pipes including an outer riser pipe and inner strings of casing. Drilling wells and/or production of oil and gas or like operations are conducted through these casings. The tension of the inner casing string is transmitted to the floating vessel through the upper end of the outer riser pipe. The system prevents excessive buildup of stresses in the upper end of the inner casing due to the bending caused by excursions caused by the waves, the wind and the current.

Abstract: A marine riser having a pair of hydraulic lines, such as choke and kill lines, secured thereto and substantially parallel to one another providing track means extending along substantially the full length of a multiple joint riser string for transporting a carriage along the riser from near the top to the bottom. The invention also includes a carriage adapted to travel along such track and also includes television camera and lights as well as manipulator means for performing various functions on a blow-out preventer stack and wellhead connector as well as associated equipment positioned at the lower end of the marine riser.

Abstract: An oil production system for producing oil at an offshore location comprises a floating storage vessel to receive the produced oil, the vessel having means for dynamic positioning and being connectable to a subsea well head by a riser and having means for separating the associated gas from the produced oil and employing the separated gas as fuel for the dynamic positioning.Re-entry of the subsea well is effected by providing the riser with means for effecting a simultaneous stab connection with the production bore and hydraulic control system lines without orientation.

Abstract: A marine compliant riser system is provided for attaching a flexible flowline to a buoyed conduit riser section. The improved system includes a novel yoke assembly for receiving flexible flowline with a means for retaining a terminal portion of the flexible flowline at a substantially vertical catenary departure angle. Pivotally-mounted loading gates or a yoke beam support the flexible flowlines during installation and/or replacement on the yoke. Connection means are mounted on the buoy section for establishing fluid communication between the flexible flowline and conduit at the buoyed riser section.An installation method is disclosed for completing the improved riser system in deepwater. This system is particularly adapted for oil and gas flowlines, service lines, hydraulic control and electrical conduits for connecting a subsea wellhead or production gathering eqiupment to a surface facility.

Abstract: Underwater well apparatus in which the handling string for manipulating a handling tool to, e.g., orient and land a multiple string tubing hanger includes a power portion in the form of a single metal piece having a plain cylindrical outer surface to be presented to the blowout protectors, so that orientation of the handling string relative to the protectors is not necessary, and also having through passages for communicating with the tubing strings, and coupling means for attaching the handling tool to the handling string.

Abstract: A method for drilling wellbores from an offshore platform to penetrate a subterranean formation using a combination of surface drilling techniques and subsea drilling techniques to achieve an improved effectiveness by avoiding the necessity for large conduits communicating the ocean floor and the offshore platform.

Abstract: A cable clamp for securing a control cable to a kill or choke line in a mud riser used in offshore drilling of oil and gas wells is described. The cable clamp is comprised of two portions, a fixed portion which remains secured to the kill or choke line and a removable portion which can be engaged to or quickly released from the fixed portion to secure or disengage the control cable. The fixed portion includes a U-clamp, and the removable portion includes cooperating hinged members, each member mounting resilient pad and both members for securing said hinged members together to clamp said cable.

Abstract: An offshore marine structure for drilling wells into the ocean floor including a floating vessel which carries the necessary drilling equipment. A riser which extends from the vessel to a well head at the ocean floor, encloses a drill string and permits circulation of the drilling mud and fluids. The riser is comprised of at least two detachably connectable segments, one of which can be moved with the floating vessel, while the other remains buoyantly in place until such time as the two segments are reconnected.

Abstract: A tensioner device which operates in conjunction with an oil production riser incorporates a gimbal device having two relatively movable elements. One of said elements is connectible to the riser and to one of the relatively movable members of at least one pair of tensioner cylinder and piston units and the other member is connectible to a platform supporting the tensioner device. Guiding members carried by the other element of the gimbal device are operative to guide the gimbal device in a direction axially of the riser.

Abstract: A riser for production of oil and gas in a marine location with the riser connected to the casing supported at the mud line of a body of water and extending upward in the water to a tension moored floating structure. The riser includes a flexible joint near its connection to the casing and is supported at its upper end from the floating structure and is also supported from the floating structure at a point between 50 and 175 feet below the water level. A production string extends upwardly from the producing zone through the casing, the flexible joint and the riser to the floating structure and wellhead equipment is supported on such riser. Centralizers are provided for the production string with the centralizer immediately above the flexible joint being between 35 to 65% of the total distance between such centralizer and the centralizer positioned immediately below the flexible joint.

Abstract: A riser column particularly for use in deep water comprises a central tube connectable by its lower end to a submerged installation, for example a well, and including means permitting the central tube to oscillate relative to the installation, and connected at its upper end to a suspension table associated with a surface support, for example a platform, and bearing support means intermediate its ends at a level below that at which waves are effective, and a plurality of satellite tubes arranged around the central tube, each satellite tube having a bottom part extending from the intermediate support means to the submerged installation and a removable top part extending from the support means to suspension table and releasably connected to the bottom part thereof for withdrawal from the column following disconnection of the column from the installation, for example, in the event of a storm.

Abstract: A blowout prevention system for an offshore structure positioned on the underwater bottom in a body of water which contains moving ice masses that could force the structure off location wherein a surface blowout preventer stack for conventional well control is connected to the upper end of a riser with the lower end of the riser being disconnectably connected to a subsurface blowout preventer stack which provides the necessary well control should the structure be forced off location. The subsurface stack is positioned on a wellhead located in a chamber in the subsea bottom and is disconnectably connected to the riser so that the riser may be quickly removed from the subsea bottom should the structure be forced off location.