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 method of recovering casing in a wellbore using a vibratory casing recovery bottom hole assembly. In a vibratory casing recovery bottom hole assembly having a casing spear, a flow modifier and one or more further elements including a shock sub. The flow modifier produces cyclic variations in fluid flow through the assembly at a first frequency and at least one of the elements is configured to have a natural or resonant frequency when vibrated to be near or at the first frequency. By tuning elements of the bottom hole assembly to be close or at the frequency of the output of the flow modifier, the dynamic amplification factor of the system is maximised and longer lengths of casing can be recovered. A method of recovering casing using the vibratory casing recovery bottom hole assembly is also described. Further embodiments include a casing cutter and a hydraulic jack.

Abstract: A vibratory casing recovery bottom hole assembly and a method of recovering casing in a wellbore. The vibratory casing recovery bottom hole assembly includes a casing spear, a flow modifier and a dynamic amplification tool. The flow modifier produces cyclic variations in fluid pressure through the assembly at a first frequency and the bottom hole assembly is configured to have a natural or resonant frequency when vibrated to be near or at the first frequency. The dynamic amplification tool induces vibration in the bottom hole assembly while ensuring the dynamic amplification factor of the system is greater than one so as to transmit maximum vibration to the casing at the casing spear. Embodiments of dynamic amplification tools are described.

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 method and apparatus for casing recovery for well abandonment. A string is run-in, the string including a hydraulic jack (18), an anchor (28), a casing spear (20), a downhole flow pulsing device (22) and a pressure drop sub (24). The casing spear grips an upper end of the length of casing to be pulled. The anchor is set in casing of a greater diameter above the length of cut casing. Fluid pumped through the string and through the pressure drop sub will increase fluid pressure at the hydraulic jack to a first fluid pressure (78). Fluid pumped through the downhole flow pulsing device will vary the fluid flow superimposing a cyclic pressure (82) on the first pressure (78), causing oscillation of an inner mandrel (30) of the hydraulic jack. The jack moves the oscillating inner mandrel upwards relative to the anchor to pull the length of casing.

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 method of recovering casing in a wellbore using a vibratory casing recover), bottom hole assembly. In a vibratory casing recover), bottom hole assembly having a casing spear, a flow modifier and one or more further elements including a shock sub. The flow modifier produces cyclic variations in fluid flow through the assembly at a first frequency and at least one of the elements is configured to have a natural or resonant frequency when vibrated to be near or at the first frequency. By tuning elements of the bottom hole assembly to be close or at the frequency of the output of the flow modifier, the dynamic amplification factor of the system is maximised and longer lengths of casing can be recovered. A method of recovering casing using the vibratory casing recover), bottom hole assembly is also described. Further embodiments include a casing cutter and a hydraulic jack.

Abstract: A vibratory casing recovery bottom hole assembly and a method of recovering casing in a wellbore. The vibratory casing recovery bottom hole assembly includes a casing spear, a flow modifier and a dynamic amplification tool. The flow modifier produces cyclic variations in fluid pressure through the assembly at a first frequency and the bottom hole assembly is configured to have a natural or resonant frequency when vibrated to be near or at the first frequency. The dynamic amplification tool induces vibration in the bottom hole assembly while ensuring the dynamic amplification factor of the system is greater than one so as to transmit maximum vibration to the casing at the casing spear. Embodiments of dynamic amplification tools are described.

Abstract: A downhole casing cutting and removal assembly (10) and method of use thereof, the assembly comprising a work string (23) with a cutting mechanism (18) and plurality of resettable anchor mechanisms (20B-20D). The arrangement allows a test pull to be made following the cut by an anchor mechanism closer to the upper end of the cut casing section than an anchor mechanism (20B-20D) located close to the cutting mechanism. Time is thus saved by not having to raise and lower a single anchor mechanism (20B-20D) between the cutting position and the upper end of the cut casing section to undertake a test pull.

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: 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: 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 downhole casing cutting and removal assembly (10) and method of use thereof, the assembly comprising a work string (23) with a cutting mechanism (18) and plurality of resettable anchor mechanisms (20B-20D). The arrangement allows a test pull to be made following the cut by an anchor mechanism closer to the upper end of the cut casing section than an anchor mechanism (20B-20D) located close to the cutting mechanism. Time is thus saved by not having to raise and lower a single anchor mechanism (20B-20D) between the cutting position and the upper end of the cut casing section to undertake a test pull.

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.

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: A valve assembly for use in a wellbore of an oil, gas or water well, having a valve seat to seat a valve closure member such as a ball, and a control member that is adapted to cycle the valve assembly between first and second configurations of the valve assembly when the ball is seated on the seat. The valve assembly may be adapted to return the valve assembly to the first configuration when the valve closure member is seated on the seat, and may repeatedly, continuously and/or sequentially cycle from first to second configurations and back to first configuration to open and close an outlet port while the same valve member is seated on the seat. The valve seat may comprise first and second seat members and retain the ball in a cleft between the first and second seat members.

Abstract: A method and apparatus for casing recovery for well abandonment. A string is run-in, the string including a hydraulic jack (18), an anchor (28), a casing spear (20), a downhole flow pulsing device (22) and a pressure drop sub (24). The casing spear grips an upper end of the length of casing to be pulled. The anchor is set in casing of a greater diameter above the length of cut casing. Fluid pumped through the string and through the pressure drop sub will increase fluid pressure at the hydraulic jack to a first fluid pressure (78). Fluid pumped through the downhole flow pulsing device will vary the fluid flow superimposing a cyclic pressure (82) on the first pressure (78), causing oscillation of an inner mandrel (30) of the hydraulic jack. The jack moves the oscillating inner mandrel upwards relative to the anchor to pull the length of casing.

Abstract: A filter device housed within a body component. The filter device can include an outer filter and an inner filter positioned coaxially within the outer filter. The outer and inner filters may be composed of a material having mesh, slots, holes, or any other openings being of a sufficient size and shape to restrict passage of items of a predetermined size or larger. Formed between the inner and outer filters is a first annular space into which fluid that is provided down the drill string may enter. The filter device may also include a valve within the internal bore which regulates passage of wellbore fluid provided to the drill string, or for a wireline or slickline, to pass through the filter device in order to access other components of the drill string downhole from the filter device.

Abstract: A flow diverter including a bypass element to divert at least a first portion of drilling fluid from a drill string to the borehole annulus. The first portion of fluid, or bypass flow, may be provided to the borehole annulus to clear cuttings generated by a drill bit of a BHA. The remaining fluid flow, or BHA flow, may be expelled through the bottom of the BHA. The fluid discharged through the BHA may enter the annulus and flow upward with the fluid flow diverted through the flow diverter to aid in clearing cuttings. The flow diverter also includes a choke housing disposed concentrically within a drill collar and containing a plurality of chokes to regulate bypass flow. An actuation system may be coupled to the flow diverter to control opening/closing of the chokes and to measure flow rate of the first portion of fluid and/or the remaining fluid.

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.