Abstract: A joint for joining the ends of two pipes (12, 14) has a socket (or box) on the end of one pipe (14) into which the end (30) of the other pipe is inserted. The part (36) of the socket which surrounds the inserted pipe has an external tapered surface (38). A correspondingly tapered sleeve (42) surrounds the socket and can be moved axially to apply a compressive force to the taper on the socket which is thus compressed inward against the inserted pipe end to frictionally grip the inserted pipe end.

Abstract: In the drilling of a well, a dedicated drilling wellhead (520) mounted at the top of the casing cluster whilst the well is being drilled. At the end of drilling, a seal ring or sleeve (534) which during the drilling phase has the function of an annular sleeve isolating the well bore pressure from the production annulus space (540), is manipulated into an alternative position in which it acts to block the annular space (540) thereby acting as a temporary abandonment seal. A further plug seal is fitted in the well bore. The well is now temporarily sealed and the drilling wellhead can then be removed and can be reused on another well during the drilling phase of that well. A production wellhead (550,556) which has a cantilever christmas tree fitted on its side over a production wellhead (557) which can accept a conventional christmas tree on top is then fitted on to the casing hanger cluster.

Abstract: A washout arrangement for a well where a washout process is to take place to wash cement out of an annulus between two concentric casings 10, 16. Washports 36 are provided in a casing hanger 18, and an axially movable, telescopically extending lower body 40 is provided in a running tool 26 which is to engage with the casing hanger. When the running tool and casing hanger are engaged with each other, the lower body 40 can be moved axially (for example by mounting the lower body on a thread within the running tool and then rotating the lower body) between a position where it closes the washports and a position where the ports are open.

Abstract: A clamp for clamping two concentric tubes, typically two concentric tubes 2,4 in an oil or gas well. The clamp has two axially movable tapered components 6,7 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 12 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 5 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 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.