Abstract: A downhole actuator (16) includes a piston (15) within a chamber (17) on which fluid can act on either side to hydraulically activate the actuator. A hydrostatic equilibrium device (18) and a valve (14) are mounted around the hydraulic actuator. With a radial port (28) of the hydrostatic equilibrium device closed and the valve closed to seal the string, pumping fluid through the string operates the actuator. Pressure overbalance prevents movement of the piston (15). The radial port (28) is opened to drain fluid from the string until equilibrium is reached with the annular volume and the piston (15) can be moved.

Abstract: A single trip casing cutting and pulling assembly which includes a casing spear (12), a mud motor (16) and a casing cutter (18), wherein a valve (14) is located between the casing spear (12) and the mud motor (16). The casing spear is operated by fluid flow from surface and the valve (14) prevents operation of the casing cutter (18) until the casing spear (12) is set and casing cutting is required. A method is described for cutting and pulling casing which does not require any rotation of the drill string to operate any part of the casing cutting and pulling assembly. An embodiment is described which includes retrieving the seal assembly (48) on the same trip. Further embodiments describe performing an integrity test and a circulation test on the same trip with the option of making further cuts at shallower depths on the same trip until a section of cut casing can be recovered.

Abstract: A technique facilitates reducing or eliminating the risk of premature actuation of a liner hanger system and/or premature release of a miming tool. According to an embodiment, the technique utilizes a running string for deploying a liner hanger assembly having a liner hanger which may be actuated at a desired location to suspend a liner/casing from a surrounding casing string. An anti-preset module may be used in cooperation with the liner hanger to prevent premature actuation of the liner hanger. By way of example, the anti-preset module may use pressure equalization between a region within the miming string and a region between the miming string and the liner hanger to prevent pressure imbalances which could actuate the liner hanger. Additionally, a locking mechanism, e.g. releasable lock dogs, may be used to temporarily lock the liner hanger against premature actuation.

Abstract: A downhole tool which allows the selective operation of a second fluid pressure activated tool below a first fluid pressure activated tool on a tool string in a well. The downhole tool has a piston sleeve moveable inside a cylindrical body between a first position in which a small flow area is provided through the tool and a second position in which a larger flow area is provided. The piston sleeve is held in the first position by a magnet and the first fluid pressure activated tool can be operated by increasing fluid pressure above the tool up to a cracking pressure level which matches the pulling strength of the magnet. Increasing fluid pressure to the cracking pressure therefore selectively moves the piston sleeve to the second position in which the second fluid pressure activated tool can be operated. The downhole tool is resettable.

Abstract: The invention provides a downhole tool for cutting a wellbore casing. The downhole tool comprises a gripping mechanism for gripping a section of wellbore casing and a cutting mechanism configured to cut the casing. The grip mechanism is configured to grip a range of casing diameters.

Abstract: A downhole actuator (16) includes a piston (15) within a chamber (17) on which fluid can act on either side to hydraulically activate the actuator. A hydrostatic equilibrium device (18) and a valve (14) are mounted around the hydraulic actuator. With a radial port (28) of the hydrostatic equilibrium device closed and the valve closed to seal the string, pumping fluid through the string operates the actuator. Pressure overbalance prevents movement of the piston (15). The radial port (28) is opened to drain fluid from the string until equilibrium is reached with the annular volume and the piston (15) can be moved.

Abstract: A resettable mechanism and a method of controlled actuation of a hydraulically operated downhole tool to allow selective operation of the downhole tool in a wellbore. The resettable mechanism provides an inner sleeve member which is longitudinally moveable between a first and second position which opens and closes a fluid pathway to at least one actuation port on the downhole tool. Movement of the inner sleeve member is controlled via an indexing mechanism operated by drop balls. An embodiment of a casing recovery system is described mechanism operated wherein a downhole pulling tool is selectively actuated so as to prevent operation of the pulling tool while a hydraulically operated casing cutter is cutting casing.

Abstract: Method and apparatus for single-trip cementing and casing cutting for well abandonment and slot recovery. Using a tool string including a casing cutter and a stinger, where the casing cutter has a central through bore including a wall to isolate the cutting assembly from the cement, cement can be passed through the cutter and deposited using the stinger to form a plug. Embodiments of casing cutters are provided for parting an upper length of casing from a lower length of casing.

Abstract: A circulation test tool and method of performing a circulation test in a wellbore during single-trip casing cutting and removal. An anchor mechanism (20), a mechanical-set retrievable packer (22) and a cutting mechanism (18) allow gripping and cutting of casing (14) with the mechanical set-retrievable packer (22) being set after the cut to carry out the circulation test. The well is kept under control during the cut by application of tension on the drill string to set the packer (22) at any time. The arrangement provides full annulus flow pass at the packer during cutting. Embodiments describe additional features of a drill to dress a cement plug or a settable bridge plug.

Abstract: Method and apparatus for removing a section of well tubing. The well tubing (24) is milled in an upward direction on a hydraulic tensioning device (14) which maintains a constant load on the section mill so that long sections of tubing can be removed in a near continuous procedure on a single trip into the well. The hydraulic device includes an indicator (30) to provide a signal as the device nears each end of a stroke to inform a user that: the section mill is about to bottom out and the work string needs to be raised to extend the device; and the device is fully extended and can begin another stroke. Embodiments are described for use in a rigless well abandonment procedure.

Abstract: Method and apparatus for single-trip cementing and casing cutting for well abandonment and slot recovery. A casing cutter is described which has a central through bore including a wall to isolate the cutting assembly from cement being passed through the casing cutter. The casing cutter is run in a cased well bore, cementing occurs through the casing cutter to form a cement plug and then the casing is cut. Embodiments of casing cutters are provided for parting an upper length of casing from a lower length of casing.

Abstract: A downhole tool which allows the selective operation of a second fluid pressure activated tool below a first fluid pressure activated tool on a tool string in a well. The downhole tool has a piston sleeve moveable inside a cylindrical body between a first position in which a small flow area is provided through the tool and a second position in which a larger flow area is provided. The piston sleeve is held in the first position by a magnet and the first fluid pressure activated tool can be operated by increasing fluid pressure above the tool up to a cracking pressure level which matches the pulling strength of the magnet. Increasing fluid pressure to the cracking pressure therefore selectively moves the piston sleeve to the second position in which the second fluid pressure activated tool can be operated. The downhole tool is resettable.

Abstract: A downhole anchor mechanism (110) which can be set on at least two successive standard diameters of casing (232). The tool body has a recess into which a split cone (70) is located. The increased thickness of the split cone (70) provides for a greater thickness of slip (90), giving increased radial travel of the slips 90 when moved axially over the split cone (70). The cone (70) and slips (90) are profiled to provide two ramps/slopes for increased structural integrity and a greater ramp angle to reduce the axial travel of the slips to achieve the increased radial travel. The downhole anchor mechanism (110) provides anchoring of a work string on two standard diameters of casing in a single trip in a wellbore.

Abstract: A well bore integrity test tool (10) and method of pressure integrity testing a well bore by performing positive and negative pressure tests in a well bore in multiple locations in the well and on the same trip as other operations in the well bore. The tool includes a resettable anchor mechanism (20) and a tension set packer assembly (22). An embodiment of performing a dress-off, integrity testing, casing cutting and pulling in a single trip for well abandonment is described.

Abstract: An apparatus and method for anchoring a string at a well for the purpose of cutting a tubular (30) which includes an anchor mechanism (110) being a tubular body (60) having a cone (116) arranged around the body, a plurality of selectively operable slips (112), and a plurality of pistons (44), there being a piston for each slip, each piston being operable to act to move each slip independently over the cone between a retracted configuration and an extended configuration wherein the outer surface (96) of each of the slips contacts the inner surface of the tubular (30). The method includes the action of cutting the tubular (30) with a cutting tool (102) which is stabilised by the slips (112).

Abstract: A single trip casing cutting and pulling assembly which includes a casing spear (12), a mud motor (16) and a casing cutter (18), wherein a valve (14) is located between the casing spear (12) and the mud motor (16). The casing spear is operated by fluid flow from surface and the valve (14) prevents operation of the casing cutter (18) until the casing spear (12) is set and casing cutting is required. A method is described for cutting and pulling casing which does not require any rotation of the drill string to operate any part of the casing cutting and pulling assembly. An embodiment is described which includes retrieving the seal assembly (48) on the same trip. Further embodiments describe performing an integrity test and a circulation test on the same trip with the option of making further cuts at shallower depths on the same trip until a section of cut casing can be recovered.

Abstract: A resettable mechanism for preventing the accidental actuation of a load set downhole tool and method of use. The resettable mechanism provides a collet (52) and a detent (56) with a collet ring arranged to ride over the detent under a load in excess of the operating load of the downhole tool and the collet load. Reversing the loading resets the mechanism and the downhole tool. A disengagement assembly (66) is described to disenable the detent (56) and operate the downhole tool at the operating load. Embodiments to a retrievable mechanical tension-set packer and a casing cutting and removal system are described which prevent premature actuation of the packer when run from floating structures.

Abstract: The invention provides a method of determining the condition of a cement bond of a casing in a wellbore. The method comprises perforating a tubing in the wellbore at a zone of interest and displacing a settable composition through the perforations into the annulus between the casing and tubing to secure the tubing. The method also comprises cutting the tubing and assessing the status of the cement bond of the casing.

Abstract: A method for removing one or more control lines (15) in a well (1), the control lines (15) running in an annulus behind a tubular (7) in the wellbore, during a well abandonment procedure comprising the steps: perforating the tubular (7) at a location adjacent the one or more control lines (15); displacing a self-supporting settable composition (21) through the perforations (20) into the annulus (18) to secure the one or more control lines (15) in place; cutting the tubular (7) and the one or more control lines (15) at the location of the self-supporting settable composition (21); washing away the self-supporting settable composition (21); and removing at least a portion of the one or more control lines from the wellbore. Embodiments are described for control lines (15) run in an annulus (18) between production tubing (7) and casing, pulling the production tubing (7) with the control lines (15), and milling the production tubing and control lines in a rigless method for well abandonment.

Abstract: Apparatus, and methods of use, where the apparatus includes a cylindrical tool main body defining an axial centerline, the main body having a first bladed magnet section having at least one blade extending substantially perpendicular from the axial centerline at a first angle, a second bladed magnet section having at least one blade extending substantially perpendicular from the axial centerline at a second angle, and a hardfaced cylindrical section disposed between the first bladed magnet section and the second bladed magnet section, wherein the outer circumference of the hardfaced cylindrical section defines the outer circumference of the tool main body.