Abstract: A subsea primary separating vessel (2,22) is installed close to the wellhead (1,31) of an oil producing well to effect primary separation of the liquid and gas phases of the fluids produced. A line (3,23) connected to the top of the separating vessel allows separated gas to flow to a gathering vessel (8,28) located at any gathering center. At least one flow line (4,5,24) connects the lower part of the separating vessel to a vessel (9,29) located at any gathering center. When the volume of liquid phase which separates out within the at least one flow line begins to exert a back pressure which adversely affects production from the well, pressurized gas can be injected into the flow line(s) for a specific period of time in order to promote the flow of liquid gas to the vessel (9,29). If it is desired that flow efficiency should be increased a mechanical interface driven by the pressurized gas may be used to encourage flow of the liquid phase.

Abstract: A pressure compensated plug for use with subsea trees is described in which a reservoir of compressible fluid is located from a cavity within a horizontal tree (10) whereby allowing temperature induced volume changes to be absorbed by the compressible fluid without resulting in significant increase in pressure. This is achieved by providing a pressure compensation apparatus (80) in the cavity, the apparatus comprising a housing (82) with a floating piston (86) in a chamber (84). The lower face (96) of the chamber is exposed to compressible fluid in the form of an inert gas, such as nitrogen, which is pre-charged at the surface to the appropriate hydrostatic pressure of the seabed. The volume of gas trapped between the lower piston face and the lower face of the cylinder forms the gas reservoir (94). A compensation cylinder can be attached to the upper section of the lower plug (70) and run and retrieved at the same time as the plug, thereby reducing the number of intervention runs.

Abstract: A heat pipe heat exchanger for regulating the temperature of a wellstream fluid conveyed in a subsea pipeline from a wellhead has an annular reservoir surrounding a section of pipeline adjacent the wellhead. One or more heat pipes extend from the annular reservoir into the seawater. In a heat removal configuration, a working fluid is contained within the annular reservoir. The working fluid boils and is evaporated by heat from the wellstream fluid and forms a vapor, which rises upwardly into and is condensed within the heat pipes, releasing heat into the surrounding seawater. The recondensed working fluid flows back down into the reservoir to repeat the cycle. In a heat providing configuration, the working fluid is contained in the heat pipes, where it is boiled by heat transferred from the surrounding seawater. The resulting vapor rises upwardly into the annular reservoir and the heat is transferred to the cooler wellstream fluids.

Abstract: A drill stem diverter tool for removing gelled drilling fluid and filter cake from the side of a well bore. The apparatus comprises a housing adapted to be connected into a drill string. The housing includes a plurality of diverter ports which communicate a central opening of the housing with a well annulus. A valve means which can be moved from a first position which blocks the diverter ports to a second position which opens the diverter ports is disposed in the central opening. The diverter ports are angled and offset from the center line of the housing so that the fluid exiting the ports creates a turbulent circular motion. A stop is provided to limit the movement of the valve means. The valve means may also be moved from its second position back to its first position to block communication to the well annulus through the diverter ports.

Abstract: A method to reduce vortex-induced vibrations in subsea risers is provided wherein a flexible fairing is provided surrounding the riser. The flexible fairing will reduce displacements caused by vortex induced vibrations regardless of the direction of the current and will be tolerant of marine life growth.

Abstract: A subsea abandoned wellhead protection system which may be installed underwater without the need for underwater assistance from divers or the like, the system allowing full site preparation and installation from the surface. The present invention teaches a new and unique system for the lowering and centering of the shelter over the wellhead, as well as a new system for the preparation of the installation site, including the removal of debris from the site and excavation of the ground surface area about the abandoned wellhead via a remote, fluid actuated, integrated excavation system.

Abstract: A gas venting apparatus for an offshore installation which vents excess gas produced from a liquid producing well. Said apparatus, including a flame extinguishing feature comprised of an elongated tube which depends from the flow tip of a gas venting conductor. To extinguish an accidentally ignited gas-fed flame, and to concurrently cool the flow tip, a weighted closure plate assembly is maintained in open position at the conductor flow tip. A high velocity stream of water directed against the closure assembly urges a closure plate into sealing engagement with the gas conductor, thereby choking off the flame, and terminating the gas flow.

Abstract: An electro-hydraulic control system for subsea wellheads provides a water tight housing carrying therewithin an electric motor drive which operates a valve that is positioned adjacent but outside the water tight housing. A high ratio gear box within the water tight housing interfaces the motor drive and the valve while maintaining the flow control position of the valve such as open flow, closed flow, or incremental flow opening positions of the valving member. A dual tone multi-frequency controller activates the electric motor drive using a key pad at a remote location so that both operation of the valve and an indication of valve position can be achieved from the remote location.

Abstract: A slurry of oil-impregnated cuttings from the use of oil based drilling mud and other unwanted slurries and fluids may be injected into the annulus of a sub-sea well and then into a porous formation through which the well has passed using apparatus on a guide base surrounding the sub-sea well head. The guide base comprises a coupling for a pipe extending down from the drilling rig, a one-way isolation valve and pipework leading to the outermost housing of the well. The outermost housing has ports to carry the slurry into the outermost annulus and inner housings may also have ports to carry this slurry into inner annuli. Inter housings also have a one-way check valve to control the injection. The guide base may have a cement circulation pipework and a cement and dump valve. The guide base may also be a retrievable base so that the injection apparatus may be reused.

Abstract: A system for handling a reeled tubing including a guide, a shear for cutting the tubing and a tubing injector including upper and lower strippers and guides and an enclosure for the injector. The enclosure in one form excludes sea water in an open bottomed enclosure and the other maintains pressure in a completely closed enclosure.

Abstract: An offshore subsea well includes a wellhead to which is connected an elongated somewhat flexible riser extending to the sea surface. The riser pipe is unstayed and is buoyed at least partially by a buoyancy member connected to the riser between the sea surface and the wellhead. Flow control valves and well access components are disposed at the upper end of the riser pipe and extend only a few feet above the sea surface during a normal or calm sea condition. A production fluid flowline returns to the sea floor alongisde the riser for extension to a central platform for the reservoir. The well support system provides for a low cost surface disposed Christmas tree arrangement which does not require a fixed support platform. The buoyancy member is preferably an annular can which is connected to an upper end of an elastically bendable section of the riser and which supports a tower for a work platform and hazards to navigation aids.

Abstract: A system for handling reeled tubing including a guide, a shear for cutting the tubing, and a tubing injector including upper and lower strippers and guides and an enclosure for the injector. The enclosure in one form excludes sea water in an open bottomed enclosure and in the other maintains pressure in a completely closed enclosure.

Abstract: An improved method and apparatus for operating or setting equipment within a subsea marine wellhead from the surface having an indicating signal provided at the surface of the successful completion of such operation. The steps of the method include the lowering of a well component and the detecting and transmitting equipment on a running string from the surface; detecting the successful completion of the subsea operation, and transmitting to the surface of a signal signifying that the operations within the subsea well head have been successfully completed.

Abstract: System for the transport of an unprocessed well stream comprising a multiphase, multicomponent mixture over long distances from one or several subsea wells A to a terminal F. The well stream, which is transported in one or several pipelines (10), running via at least one well A and to the terminal F, is supplied transport pressure by means of one or several fluid driven pumps (26) in the vicinity of the wells and/or fluid driven pipeline pumps (27) along the pipelines.

Abstract: A sea bed oil producing and processing complex has a template with three bays housing pairs of modules, viz, well, gas and oil production modules. The complex includes a separator for separating oil and gas and a pump for the produced oil, and bars having pipework to carry fluids between the pairs of modules and to despatch separated gas and oil. Saddles may carry fluids across between individual modules of a pair and the complex may have facilities for artificial lift, water injection, chemical fluid injection and for test fluids. Multiples of the three bays and pairs of modules may be within a single template and a number of modules may surround a central piping template. The complex can be services and maintained in a diverless mode using a monohull vessel and an ROV.

Abstract: An arctic offshore platform adapted for use in hydrocarbon exploration and production operations conducted in relatively shallow waters with low to moderate ice environments. The arctic offshore platform of the present invention includes one or more support legs. Each support leg includes a base resting on the ocean floor, a central support column extending upward through the base to a position above the ocean surface and a sloped-sided member seated atop the base and extending upward around the central support column to a position above the ocean surface. In installation, the base and central support column are installed and secured to the ocean floor as a unit. Following this, the sloped-sided member is secured atop the base. The sloped-sided member causes ice sheets which may impact the support leg to fail in flexure, thus reducing the overall ice loadings on the support leg relative to the loading which would exist were the sloped-sided member absent.

Abstract: A marine riser anticollapse valve is disclosed for preventing a marine riser from collapsing under external sea water pressure in the event of a sudden loss of internal drilling fluid pressure. An external valve structure is provided for each of a plurality of openings in the wall of a riser pup joint. Each of the valve structures includes a cylinder having an opening in communication with a body wall opening. A piston in each cylinder is subject to sea water pressure but is prevented from opening when riser bore pressure of a sufficient magnitude is applied internally to the piston via the pup joint opening and cylinder opening. When the riser bore pressure falls, the piston is driven to an open position allowing sea water to enter the riser.

Abstract: A method for handling an underwater wellhead assembly by means of an offshore jack-up drilling rig or platform wherein the wellhead assembly is prepared on the shore or quay and is carried on the drilling rig to a preselected drilling location and lowered down therefrom to the ocean floor.

Abstract: Methods of gravel packing a subterranean well located subsea utilizing through-the-flowline techniques are disclosed in which a sand slurry is pumped downwardly through one pipe of a dual pipe string and outwardly through an H-type crossover member (14, 15) into a perforated casing area (20) until the area is fully packed. In one method, the H-type crossover member (14) is provided with a flangible plug (14h) to allow bypass of the sand slurry once the perforated casing area is filled with aggregate. In another method, the gravel packing of the perforated casing area is accomplished utilizing a special TFL tool (25) which provides for injection of the sand slurry through an H-type crossover member (15) into the perforated casing area (20).

Abstract: Apparatus for use in drilling a well from a floating vessel by means of a riser, which connects the vessel's drilling equipment to a wellhead assembly adjacent to the ocean floor. The riser moves substantially vertically in relation to the vessel, as the vessel responds to wave action. The present riser position indication apparatus is comprised of a load cell and a chain attached beneath the load cell. Movement of the riser relative to the vessel alters the length of chain suspended from the load cell, thereby altering the signal from the cell. The signal can be subsequently calibrated to represent riser position.

Abstract: A system for controlling the deviation of the path of oil or gas well conductor casing at a desired angle, curvature and orientation in the sea bottom stratum through which it is driven from an offshore platform involving the use of conductor guide(s) equipped with longitudinally disposed anti-twist bar(s) fixedly mounted thereon to prevent or arrest any twisting motion along the longitudinal axis of the casing sections which have like, anti-twist bar as the conductor sections are being lowered or driven down from the platform. Motion is arrested by means of the bars on the conductor guide(s) contacting the similar bars fixedly attached to the casing sections being driven through the conductor guides on the platform support structure. By arresting any twisting motion at this relatively elevated point, any undesired twist is minimized in the driven casing sections minimizing any undesired horizontal deviation in the enplacement of the conductor casing which would have otherwise been caused by the twisting.

Abstract: A subsea caisson or silo for housing wellhead equipment and methods of installing it is disclosed. A caisson which is sized to receive equipment that is to remain subsea has a closed top and open bottom. The caisson is lowered to the seabed and hydrostatic pressure in combination with a suction jet is used to remove the internal soil. If required the caisson may include a conical suction head located near the bottom of the caisson wall and rotatable cutting heads are fixed to its lower surface so as to cut into sea bottom material of hard consistency.

Abstract: A well head protector for a well which is located at the floor of an offshore body of water. The protector includes a plurality of discrete sub-assemblies which, for installation purposes, are initially transported to a drilling vessel and positioned above the well head. The sub-assemblies are sequentially lowered from the vessel deck and assembled above the water surface into a composite unit. The completed unit is guidably lowered by the vessel's drilling derrick to its position surrounding the well head. The deflecting elements are then lowered into place.

Abstract: Novel copolymers of N,N-dimethylacrylamide and acrylamide are disclosed where the ratio of NNDMA to AM ranges from 10:90 to 95:5. The hydrolyzed copolymer is also disclosed where hydrolysis ranges from 5% to 65% and the ratio of NNDMA to AM is 5:95 to 95:5. These hydrolyzed copolymers are useful in enhanced oil recovery operations.

Abstract: A subfloor comprising leg-supported modules and drop in panels adapted to be installed in and around a grid of Christmas trees in the well bay area of a production platform.

Abstract: A bottom-positioned well drilling platform is provided with an enclosure in the lower part thereof which forms a chamber into which returning drilling mud and cuttings can be discharged. A pump and separate return line raise the mud alone from the chamber to the top of the platform while the cuttings remain in the chamber.

Abstract: Disclosed are methods and apparatus for generating electric and hydraulic power adjacent an undersea oil well for use in operating the well-head equipment. The difference in the temperature of the oil being extracted from the well and the temperature of the surrounding sea water is utilized to generate such power.

Abstract: A novel guide member and guide member support arrangement for guiding a drill conductor from a deck portion of an offshore platform into the bottom of a body of water is disclosed. The guide member is snugly nestled against and positioned within the guide member support which directly provides lateral and vertical support for the guide member. The guide member has an upper funnel-shaped portion and a lower cylindrical portion. The guide member support comprises the plurality of connected structural members arranged in a plane for defining a support opening for the guide member. The guide member is connected to the guide member support at at least three positions.

Abstract: Described is an ocean thermal energy conversion system wherein floating, submerged and fixed drilling platforms installed offshore primarily for exploration and/or production of hydrocarbons serve also as working and supportive bases for means for producing electricity by the adiabatic expansion of hydrocarbon gases which are thereby cooled. The cooled gases are then heated by contact with the solar heated surface layers of water and thermally expand thereby actuating a turbine and an electricity producing generator. Pipelines usually installed for the transmission of gases and crude oil to the shore are used dually by running electric cables with them to bring the electricity produced by the system to on-shore consuming or storage facilities. The system also includes means for increasing the surface water temperature such as insulated pipes bringing heat-containing effluent streams from on-shore treating plants.