Abstract: A method and apparatus for connecting riser between a floating vessel and a subsea structure that reduces the size of the air tanks used and thereby allow closer positioning of the well slots and overall reduction in size of the floating vessel is disclosed. The apparatus includes an inverted hydraulically actuated connector positioned on the subsea structure and oriented to receive and sealingly attach to a complementary end connection member on the lower end of the riser string.

Abstract: An actuator for use with a subsea choke or similar apparatus is disclosed. The actuator uses a planetary roller screw mechanism to allow greater control of the torque output while allowing a fast closing of the choke when well conditions require so. A handle is positioned on one end of the actuator housing for manipulation of the actuator housing by a remotely operated vehicle, when required. A pressure responsive axially reciprocable piston is positioned around the driven shaft and controls movement thereof. Other embodiments show the actuator controlling the position of the cage in a cage type choke. A final embodiment shows the actuator configured for use on a subsea tree.

Abstract: An electrically operated valve actuator with an eddy current clutch is disclosed. The use of the eddy current clutch provides an actuator that can control the rate of closing of the valve in a predetermined linear manner to avoid slamming the valve shut in an emergency shutdown.

Abstract: A fail-safe gate valve for sub-sea use features a floating, pressure biased compensating piston whose movement prevents internal pressure buildup from opening movement of the gate. A pre-charged fluid chamber provides the bias on the balancing piston. Using unequal piston diameters reduces the charge pressure. The balancing piston is not connected to the gate so that internal pressures can be employed to act on a net area, which biases the gate toward its fail-safe position.

Abstract: A wellhead has, instead of a conventional Christmas tree, a spool tree (34) in which a tubing hanger (54) is landed at a predetermined angular orientation. As the tubing string can be pulled without disturbing the tree, many advantages follow, including access to the production casing hanger (21) for monitoring production casing annulus pressure, and the introduction of larger tools into the well hole without breaching the integrity of the well.

Abstract: A new seal system for a marine riser telescoping joint is revealed. The sealing face of the seal has tapered upper and/or lower tapered surfaces. The upper and/or lower ends can have a taper of about 1-15 degrees or alternatively the surrounding housing can have the taper with the seal ends either straight cut or tapered so that the combined tapers are in the stated range. The sealing elements are preferably nitrile or polyurethane and preferably without inserts. The upper and/or lower ends of the seal can have projections or depressions to aid in end sealing and eliminate the need for end seal rings. The new seals can be used individually or in stacks in a single housing.

Abstract: A visual signal of pressure between valve stem seals is given by a rising ring, which moves upwardly with the upper stem seal when there is pressure between the stem seals. The rising ring is held to the stem or valve body around the stem by a retaining ring. The rising ring, in its up position, precludes removal of the retaining ring.

Abstract: A connector for connecting a first tubular member to a second tubular member is disclosed, for example for connecting a riser to a wellhead in a subsea oilfield location. The second tubular member has a seating surface and comprises an engagable locking profile. The connector comprises a housing for securing the connector to the end portion of the first tubular member, the housing comprising a seating surface for contacting the seating surface of the second tubular member.

Abstract: A wellhead has, instead of a conventional Christmas tree, a spool tree (34) in which a tubing hanger (54) is landed at a predetermined angular orientation. As the tubing string can be pulled without disturbing the tree, many advantages follow, including access to the production casing hanger (21) for monitoring production casing annulus pressure, and the introduction of larger tools into the well hole without breaching the integrity of the well.

Abstract: A valve and valve actuator utilizing a disconnected piston design that separates under conditions of excessive actuator internal pressure to prevent overloading and damaging the threaded connection between the valve stem and actuator piston is disclosed. The hydraulically actuated valve actuator comprises a spring housing including a bonnet for coupling the spring housing to a valve. The spring housing includes an upper head and a packing gland that are sealingly attached to the spring housing to form an interior pressure chamber. The interior pressure chamber has a pressure responsive actuator piston disposed therein with a coil spring designed to move the actuator piston from a normally open to a fail closed position. The pressure responsive actuator piston includes a piston and a spring retainer nut that are separable after closing of the valve to prevent ambient pressure acting within the pressure chamber on the pressure responsive actuator piston from overloading the valve stem.

Abstract: An underwater well system in which an initially vertical drilling riser conduit (5A) is fixed by a template (7,13,15) at the seabed (6) in a non-vertical orientation. Drilling is carried out through wellhead (30) in the template which also includes a valve tree (28) 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 (12,14) to further templates such that a wide area of the seabed can be covered for a single drilling riser conduit.

Abstract: A gate valve actuator that utilizes a mounting ring interposed between the valve bonnet and actuator housing to allow the mounting of different sizes and types of gate valve actuators onto a given gate valve and providing rotation with respect thereto is disclosed. A split retainer ring allows the coupling between the actuator and valve bonnet to avoid the use of bolts subject to corrosion and failure. A first embodiment uses a pneumatically operated diaphragm to provide a force for opening the valve. Other embodiments use pneumatically and hydraulically powered pistons. Another embodiment shows the use of multiple springs to augment the closing force.

Abstract: A retaining apparatus, in particular an internal tree cap, for use in a wellhead having a central bore and first and second retaining means, such as a shoulder and a groove, within the bore of the wellhead. The retaining apparatus has a housing for location within the bore of the wellhead. A first engagement assembly is provided for engaging with the first retaining means in the bore of the wellhead to thereby retain the housing within the bore of the wellhead. A second engagement assembly for engaging with the second retaining means in the bore of the wellhead is also provided. The apparatus further comprises a preload assembly operable when the housing is located within the bore of the wellhead to apply a preload to the housing between the first and second retaining means. A method for retaining an assembly within a wellhead bore, in which a preload is applied between the first and second retaining means, is also disclosed.

Abstract: A riser connector is provided for connecting a riser to a wellhead assembly having a bore therethrough. The connector includes a housing having a first and a second end. The first end of the housing has an opening and is adapted for mounting to the wellhead assembly with the opening in communication with the bore of the wellhead assembly. The second end has a first opening connectable to the riser having a diameter at least the same as the inner diameter of the riser, and a second opening, having a diameter at least substantially the same as the diameter of the bore of the wellhead assembly. The housing further includes a first conduit connecting the opening in the first end of the housing to the first opening in the second end of the housing, and a second conduit connecting the opening in the first end of the housing to the second opening in the second end of the housing. In use, first well operations are conducted through the riser in the conventional manner.

Abstract: An apparatus for securing a tubular member under tension is provided, the member secured to and extending between a first and second fixed assembly. The apparatus comprises a first tubular assembly connectable at a first region to the tubular member to be tensioned and a second tubular assembly having a first and a second engageable portion, the second tubular assembly being arranged concentrically with respect to the first tubular assembly and movable longitudinally with respect to the first tubular assembly. A first engagement assembly is provided for engaging the first engageable portion of the second tubular assembly with the first fixed assembly, such that movement of the second tubular assembly toward the tubular member to be tensioned is prevented.

Abstract: An injection spool for use in the injection of a fluid, for example a slurry of drilling cuttings, into a subsea wellhead assembly has an outer housing having a central bore therethrough. The housing has a first end for connection to a wellhead assembly such that the central bore of the housing is aligned with the central bore of the wellhead assembly. An inner housing, for example an isolation sleeve, having a central bore therethrough is disposed within the central bore in the outer housing, whereby a cavity is formed between the inner housing and the outer housing. A port in the outer housing has an opening into the cavity between the inner housing and the outer housing, through which a fluid may be injected. The inner housing has a portion extending from within the outer housing beyond the first end of the outer housing for forming a cavity within a wellhead assembly to which the injection spool is connected.

Abstract: A pre-combustion chamber assembly for an internal combustion engine is disclosed having an inner housing having a receiver for receiving a spark plug and an inlet for fuel. A connector is provided for securing the pre-combustion chamber in a spark plug well of the internal combustion engine. An outer housing has a first end and a second end and extends around the inner housing, with a chamber being defined between the inner and outer housings. The outer housing is releasably retained around the inner housing so as to allow relative movement between portions of the inner and outer housings while maintaining the integrity of the chamber. A method of modifying an internal combustion engine and an internal combustion engine incorporating the pre-combustion chamber are also provided.

Abstract: An actuator for use with a subsea choke or similar apparatus is disclosed. The actuator uses a planetary roller screw mechanism to allow greater control of the torque output while allowing a fast closing of the choke when well conditions require so. A handle is positioned on one end of the actuator housing for manipulation of the actuator housing by a remotely operated vehicle, when required. A pressure responsive axially reciprocable piston is positioned around the driven shaft and controls movement thereof. Other embodiments show the actuator controlling the position of the cage in a cage type choke. A final embodiment shows the actuator configured for use on a subsea tree.

Abstract: The consequences of any failure of a blow out preventer assembly to operate correctly in an emergency can be far reaching. Thus, there is provided an apparatus for registering parameters in the bore of a member which is, in use, connected to a pressurised housing, the apparatus comprising: an electro-control package for attachment, in use, to the member; a test assembly placed, in use, in the member; the electro-control package and the test assembly having means for sending signals to and receiving signals from one another.

Abstract: An exhaust system for a two-cycle internal combustion engine combusting a normally gaseous hydrocarbon as fuel, the engine comprising a cylinder having an exhaust port in communication with an exhaust manifold. The exhaust system comprises an exhaust gas inlet connectable to the exhaust manifold of the internal combustion engine and an exhaust gas outlet spaced from the exhaust gas inlet in the direction of flow of exhaust gas through the system. A first tubular portion is disposed between the exhaust gas inlet and outlet, the first tubular portion diverging in the direction of flow. A second tubular portion is disposed between the exhaust gas inlet and outlet and spaced from the first tubular portion in the direction of flow, the second tubular portion converging in the direction of flow.