Abstract: A method of expanding tubing downhole comprises providing a section of expandable tubing of a first diameter, and axially compressing the tubing to induce buckling, such that the buckled portion describes a larger second diameter. The resulting diametric expansion may be utilised to anchor or seal the tubing within a larger bore.

Abstract: A method of expanding tubing comprises applying a varying fluid pressure across the wall of the tubing. The variation in pressure may be achieved by varying one or both of the fluid pressure within the tubing and the fluid pressure externally of the tubing. A body of varying volume may be located in a volume of fluid associated with the tubing. Alternatively, the volume of a body of fluid associated with the tubing may be varied by movement of a wall portion defining a boundary of the volume, which wall portion may be associated with an oscillator or a percussive or hammer device. In other embodiments a pressurised fluid source may be provided, and the fluid may be supplied at varying pressure from the source. An increase in pressure within the tubing may be accompanied by a reduction in pressure externally of the tubing.

Abstract: Methods and apparatus for shaping pipes, tubes, liners, or casing at downhole locations in wells. Use is made of rollers bearing radially outwards against the inside wall of the pipe (etc.), the rollers being rolled around the pipe to cause outward plastic deformation which expands and shapes the pipe to a desired profile. Where one pipe is inside another, the two pipes can be joined without separate components (except optional seals). Landing nipples and liner hangers can be formed in situ. valves can be deployed to a selected downhole location and there sealed to the casing or liner without separate packers. Casing can be deployed downhole in reduced-diameter lengths and then expanded to case a well without requiring larger diameter bores and casing further uphole. The invention enables simplified downhole working, and enables a well to be drilled & produced with the minimum downhole bore throughout its depth, obviating the need for large bores.

Abstract: A method and apparatus is provided for drilling and lining a wellbore in one downhole trip. The method comprises mounting a drill bit on a drill string including a section of expandable tubing and providing a tubing expander in the string, then rotating the drill bit and advancing the drill string through a bore, then passing the expander through the expandable tubing to expand the tubing, wherein the expandable tubing is deformed by compressive plastic deformation of the tubing with a localised reduction in wall thickness, resulting in a subsequent increase in tubing diameter, and then retrieving the drill bit from the bore through the expanded tubing.

Abstract: A method and apparatus is provided for drilling and lining a wellbore in one downhole trip. The method comprises mounting a drill bit on a drill string including a section of expandable tubing and providing a tubing expander in the string, then rotating the drill bit and advancing the drill string through a bore, then passing the expander through the expandable tubing to expand the tubing, wherein the expandable tubing is deformed by compressive plastic deformation of the tubing with a localised reduction in wall thickness, resulting in a subsequent increase in tubing diameter, and then retrieving the drill bit from the bore through the expanded tubing.

Abstract: A method of expanding tubing comprises locating an expansion device in tubing to be expanded, vibrating one or both of the tubing and the expansion device, and translating the expansion device relative to the tubing, the vibration acting to reduce friction between the tubing and the device.

Abstract: A method of expanding tubing comprises locating an expansion tool in a section of tubing to be expanded, applying a fluid pressure to the tubing to create a fluid pressure expansion force and induce a hoop stress in the tubing, and applying a mechanical expansion force to the tubing via the expansion tool. The combined fluid pressure expansion force and mechanical expansion force is selected to be sufficient to induce expansion of the tubing.

Abstract: There are disclosed tools and apparatus for use in expanding downhole tubing.

Abstract: A method of expanding tubing comprises the steps: providing a length of expandable tubing; locating an expansion tool, such as a cone, in the tubing; and applying impulses to the tool to drive the tool through the tubing and expand the tubing to a larger diameter. The tubing may be located downhole and may have a solid wall or a slotted wall.

Abstract: A method of providing a downhole seal, such as a packer, in a drilled bore between inner tubing and outer tubing comprises: providing an intermediate tubing section defining a seal arrangement for engaging with the inner tubing; and radially plastically deforming the intermediate tubing section downhole to form an annular extension. The extension creates a sealing contact with the outer tubing.

Abstract: A method of removing produced fluid from a well producing both gas and liquid comprises utilising produced gas flowing from a formation to power a produced liquid pump. The produced liquid from the pump and the produced gas are carried towards surface in separate fluid streams, and may be commingled closer to surface.

Abstract: An apparatus and method for expanding a lower string of casing into frictional contact with an upper string of casing, and thereby hanging the lower string of casing onto the upper string of casing is provided. The apparatus essentially defines a lower string of casing having a scribe placed into the top end thereof. The lower string of casing is run into the wellbore, and positioned so that the top end overlaps with the bottom end of an upper string of casing already cemented into the wellbore. The top end of the lower casing string is expanded below the depth of the scribe into frictional contact with the upper string of casing. At the same time, or shortly thereafter, the top end of the upper string of casing is expanded. As the portion of the lower casing string having the scribe is expanded, the casing severs into upper and lower portions. The upper portion can then be removed from the wellbore, leaving a lower string of casing expanded into frictional engagement with an upper string of casing.

Abstract: Oilfield cleaning apparatus is provided for cleaning the inner wall of an oilfield tubular. The apparatus comprises a body to be introduced into the tubular, the body being provided with annular cleaning elements. Furthermore a rotary drive acts to oscillate the cleaning elements in contact with the inner wall of the tubular to scrape debris from the inner wall with the cleaning element. Each cleaning element is mounted on a rotary bearing member which is inclined relative to its axis of rotation so as to cause the cleaning element to be oscillated axially in contact with the inner wall as the bearing member is rotated, Also a catcher tube is provided to catch the heavier debris which is not washed away by the flow of fluid up the borehole. Such apparatus provides an active cleaning action which is particularly effective in removing deposits from the inner wall of the tubular.

Abstract: A method of forming expandable downhole tubing (10) comprises the steps of: providing a tubing section (12) of a first diameter; forming apertures in the tubing section (12); and then reducing the diameter of the apertured tubing section.

Abstract: A method and apparatus is provided for drilling and lining a wellbore in one downhole trip. The method comprises mounting a drill bit on a drill string including a section of expandable tubing and providing a tubing expander in the string, then rotating the drill bit and advancing the drill string through a bore, then passing the expander through the expandable tubing to expand the tubing, wherein the expandable tubing is deformed by compressive plastic deformation of the tubing with a localised reduction in wall thickness, resulting in a subsequent increase in tubing diameter, and then retrieving the drill bit from the bore through the expanded tubing.

Abstract: A method of installing a liner in a drilled bore below a section of bore previously lined with casing comprises the steps of: running a length of liner into the bore such that at least an upper end of the liner is positioned in overlapping relation with at least a lower end of the casing; and plastically deforming a portion of the liner such that an external face of the portion forms an interference fit with an internal face of a portion of the casing. The interference fit preferably provides both hanging support for the liner and a fluid-tight seal between the liner and casing.

Abstract: A subsurface apparatus in the form a tractor is adapted for travel through a bore containing a moving fluid stream. The tractor comprises a body, a drive arrangement for moving the body in a desired direction, a member mounted on the body and adapted to be driven by the moving fluid, and a conversion arrangement for converting movement of the member to drive for the drive arrangement. The drive arrangement may include a contactless magnetic coupling and a harmonic drive.

Abstract: A method of expanding tubing downhole comprises providing a section of expandable tubing of a first diameter, and axially compressing the tubing to induce buckling, such that the buckled portion describes a larger second diameter. The resulting diametric expansion may be utilised to anchor or seal the tubing within a larger bore. The buckled portion may be used to anchor the tubing within the wellbore prior to expansion of the length of the tubing into the wellbore.

Abstract: A method of expanding tubing comprises locating an expansion tool in a section of tubing to be expanded, applying a fluid pressure to the tubing to create a fluid pressure expansion force and induce a hoop stress in the tubing, and applying a mechanical expansion force to the tubing via the expansion tool. The combined fluid pressure expansion force and mechanical expansion force is selected to be sufficient to induce expansion of the tubing.

Abstract: A method of expanding tubing downhole comprises the steps of: providing tubing (14;44) of a first diameter; running the tubing into a bore (10;40); expanding a first section of the tubing to a second diameter, and expanding a second section of the tubing to a third diameter.