Abstract: A clamp for clamping two concentric tubes, typically two concentric tubes in an oil or gas well. The clamp has two axially movable tapered components which can be pulled over one another in an axial direction to provide a contraction of internal diameter which grips the smaller diameter tube. In one embodiment, a spacer is fitted to allow the tapered components to be held apart until the tubes have been correctly positioned. The spacer is then removed, and the tapered components are drawn together to effect the clamping. A hydraulic ram can be provided to separate the tapered components should readjustment be required. In another embodiment, the larger diameter tube is made with a relatively thin wall, so that it can be distorted inwards to grip the smaller tube.

Abstract: A releasable connector (3) is described for connecting a first member (2) to a second member (1), the members (1, 2) being adapted to be inserted into one another. The releasable connector (3) comprises a lock element (4) located in a recess (5) in a surface of the first member (2) and biasing means is provided to bias the lock element (4) to a first position in which the lock element (4) extends from the recess (5) to engage a shoulder on the second member (1) to lock the first member (2) to the second member (1) against withdrawal. A movable release device (7) is located on the second member (1) so that actuation of the release device (7) causes the release device (7) to co-operate with a surface (9) of the lock element (4) to move the lock element (4) to a second position against the action of the biasing means. This causes the lock element (4) to be disengaged from the shoulder on the second member (1) with the release device (4) terminating short of the recess (5) in the first member (2).

Abstract: A casing installation system usable with tubular casing having an upper end portion and a lower portion, for anchoring the upper end portion of the casing on an outer casing string secured to a wellhead having a housing, the wellhead housing being positioned at a fixed position over a well, said casing extending upwardly to the wellhead from a location in the well at which location the lower portion of the casing is landed, the upper end of the casing being terminated by a generally annular casing hanger secured to the casing, said outer casing string having an upwardly-facing shoulder, the system also having a locking ring located on the casing hanger and movable thereon in a direction towards the lower end portion of the casing, the locking ring having means for preventing its movement on the casing in a direction away from the lower end portion of the casing in response to a force exerted on the locking ring in said direction away from the lower end of the casing, the locking ring having a downwardly-facin

Abstract: An annulus cementing and washout technique and equipment, particularly for use in an offshore oil or gas well. An annulus is formed between an outer casing and a second-outer casing, this annulus being filled with cement up to a predetermined level and washed free of cement above said level. The second-outer casing is fitted with a washout casing section having washports at the predetermined level. The washports are selectively opened and closed by axially moving a hollow sleeve mounted in the washout casing section, preferably by turning the sleeve on a screw thread using a remotely operated tool. Details of a suitable tool include spring-loaded radial dogs which engage axial slots within the sleeve. Use of the sleeve and the tool to move the sleeve enables the washports to be opened and closed as required without troublesome rotation or support of the casing.

Abstract: Surface wellhead apparatus for use in tying-back casing from a subsea structure to a surface structure or when drilling with mudline-supported casing hangers wherein the casing is maintained in tension by means of a lock member which releasably engages with a support surface, the lock member and support surface being, on release, relatively movable in a direction longitudinal of the casing and, on engagement, locked against downward movement of the casing.

Abstract: A subsea flowline connector for connecting a horizontal flowline on a seabed to a vertical riser. A flowline flange on the end of the flowline is held in a preselected location while a rigid tubular spool piece is stroked into sealing relationship therewith. The spool piece is rigid and has horizontally and vertically extending portions. It is guided so that the entire spool piece moves with the stroking and the vertical stab with the riser is made after the sealing stroke is effected.

Abstract: A through the flowline or "TFL" tool selector has a base provided with a number of spaced flowline ports and a diverter tube shiftably mounted in a housing for selective communication with the flowline ports. The base is mounted on a remotely operable connector, and the assembly is lowered onto a template beneath the sea having conduits aligned with the selector ports when the assembly is connected to the template. The inlet conduit loop of the selector assembly is also connected to an inlet conduit on the template. The connector is remotely operated to mechanically lock the selector apparatus in place.

Abstract: A manifold unit is connected to a running tool and pipe and run into position in a receptacle on a subsea template or platform to establish a flow path between fluid passages in the receptacle. Fluid supplied through the running pipe forces locking elements into locking engagement with the receptacle and the unit is forced into seating engagement in the receptacle to make a seal between the unit and the flow passages. The unit is retrievable by engaging another pipe in the unit and supplying pressure to release the locking elements.

Abstract: An underwater template has one or a plurality of pile housings through which piles are driven into the earth at the floor of the water to fix the template in place by forging the pile into grooves in the housing. The forging operations are performed by a rotary cold forge tool with expansible rollers, the tool being rotatable by a running string of drill pipe guided by a swivel which lands on and is centered by the pile, or the forging is done by explosives confined between seals within the pile section.

Abstract: A subsea template is installed on a level base provided by lowering and landing on the floor of the sea a container to which is supplied a quantity of fluent, settable material which flows to form a level upper surface on which the template is landed. The template is fixed in place by setting a pile into the floor of the sea. The receptacle is a guide base anchoring guidelines on which the template is lowered after hardening of the fluent material, or, in the case of a guidelineless installation, the base and template are lowered together and the template raised above the base during setting of the fluent material and then lowered onto the level base.

Abstract: A through the flowline or "TFL" tool selector has a base provided with a number of spaced flowline ports and a diverter tube shiftably mounted in a housing for selective communication with the flowline ports. The diverter tube is actuated by a reciprocable and rotatable piston and cam drive which shifts the diverter tube progressively from one flowline port to another. The piston is shiftable in a cylinder to which pressure fluid is supplied and then exhausted to effect actuation of the cam drive.

Abstract: A connector apparatus particularly useful in pile driving in water to enable a pile string to be released or disconnected in the vicinity of the mudline after the pile has been driven to its final depth, the connector including an upper box secured to one portion of a pin apparatus attached by a releasable mechanism to another lower portion of the pin apparatus, release of the mechanism by a suitable tool operated from a remote location enabling the drive pile string above the lower portion of the pin to be withdrawn through the water to the surface.

Abstract: A casing installation system usable with tubular casing having an upper end portion and a lower portion, for anchoring the upper end portion of the casing on an outer casing string secured to a wellhead having a housing, the wellhead housing being positioned at a fixed position over a well, said casing extending upwardly to the wellhead from a location in the well at which location the lower portion of the casing is landed, the upper end of the casing being terminated by a generally annular casing hanger secured to the casing, said outer casing string having an upwardly-facing shoulder, the system also having a locking ring located on the casing hanger and movable thereon in a direction towards the lower end portion of the casing, the locking ring having means for preventing its movement on the casing in a direction away from the lower end portion of the casing in response to a force exerted on the locking ring in said direction away from the lower end of the casing, the locking ring having a downwardly-facin