A system used to dislodge and, if necessary, sever a tubular string that is stuck within a cased wellbore. The system utilizes a jar, a plurality of plugs, and a tubular severance device. Components of the system are carried to their respective desired downhole positions by downward fluid flow within the wellbore. The jar is configured to jar the string in an effort to dislodge the string from its stuck point. The plugs are configured to fill open perforations formed in the casing in order to direct the fluid toward the stuck point and away from the perforations. If the string cannot be freed by the jar, the tubular severance device is deployed within the string above the stuck point. Detonation of the device severs the string above the stuck point.

A severing apparatus is used for severing a conduit. The apparatus includes a main body section having an upper portion, a lower portion, and an intermediate portion. A combustible charge is located in the intermediate portion, and an ignition mechanism is coupled to the upper portion for igniting the combustible charge. A nozzle head is located in the lower portion and includes an internal cavity and a nozzle portion having apertures at spaced apart positions for providing passages from the internal cavity to outside of the nozzle head. The ignition mechanism is configured to ignite the combustible charge to create a flame and combustion products and pressure in the internal cavity for moving the nozzle head relative to the lower portion so that the nozzle portion protrudes out of the lower portion for passage of the flame and hot combustion products out of the apertures to sever the conduit.

A severing apparatus is used for severing a conduit. The apparatus includes a main body section having an upper portion, a lower portion, and an intermediate portion. A combustible charge is located in the intermediate portion, and an ignition mechanism is coupled to the upper portion for igniting the combustible charge. A nozzle head is located in the lower portion and includes an internal cavity and a nozzle portion having apertures at spaced apart positions for providing passages from the internal cavity to outside of the nozzle head. The ignition mechanism is configured to ignite the combustible charge to create a flame and combustion products and pressure in the internal cavity for moving the nozzle head relative to the lower portion so that the nozzle portion protrudes out of the lower portion for passage of the flame and hot combustion products out of the apertures to sever the conduit.

An apparatus for removing a casing from a borehole penetrating a formation in one run of the apparatus in the borehole includes: a carrier conveyed in the borehole; a non-incendiary hole former on the carrier to form a hole in the casing; a fluid discharge device on the carrier to discharge a fluid into the hole to wash an exterior portion of the casing; a casing puller on the carrier and having a casing grip to grip the casing to lift the casing or a portion of the casing out of the borehole; a mechanical cutter on the carrier to cut the casing; and a valve on the carrier to control fluid energy to least one of the non-incendiary hole former, the fluid discharge device, the casing puller, and the mechanical cutter.

An apparatus for removing a casing from a borehole penetrating a formation in one run of the apparatus in the borehole includes: a carrier conveyed in the borehole; a non-incendiary hole former on the carrier to form a hole in the casing; a fluid discharge device on the carrier to discharge a fluid into the hole to wash an exterior portion of the casing; a casing puller on the carrier and having a casing grip to grip the casing to lift the casing or a portion of the casing out of the borehole; a mechanical cutter on the carrier to cut the casing; and a valve on the carrier to control fluid energy to least one of the non-incendiary hole former, the fluid discharge device, the casing puller, and the mechanical cutter.

A laser system for freeing downhole equipment includes a laser tool having an inner diameter larger than an outer diameter of the downhole equipment and a means for generating a ring-shaped collimated laser beam. The laser system further includes a work string with the inner diameter larger than the outer diameter of the downhole equipment. The laser tool is installed on the work string and the work string is lowered around the downhole equipment. Upon lowering the work string to a position in which the laser tool is located proximate to an obstruction of the downhole tool, the laser tool emits the ring-shaped collimated laser beam so as to clear out an annulus space between the downhole equipment and a wellbore wall in order to free the downhole equipment.

A laser system for freeing downhole equipment includes a laser tool having an inner diameter larger than an outer diameter of the downhole equipment and a means for generating a ring-shaped collimated laser beam. The laser system further includes a work string with the inner diameter larger than the outer diameter of the downhole equipment. The laser tool is installed on the work string and the work string is lowered around the downhole equipment. Upon lowering the work string to a position in which the laser tool is located proximate to an obstruction of the downhole tool, the laser tool emits the ring-shaped collimated laser beam so as to clear out an annulus space between the downhole equipment and a wellbore wall in order to free the downhole equipment.

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.

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.

A method for pulling casing includes disposing a casing modification and pulling tool having an element therein that includes a profile, causing the element to move radially outwardly into contact with a casing disposed radially outwardly of the tool, deforming the casing with the element, applying a load to the casing, and failing the casing at the deformation. A system for pulling casing includes a casing modification tool having an element radially displaceable into a casing disposed radially outwardly thereof, the element configured to deform the casing, a casing spear operably connected to the casing modification tool, the spear configured to apply a load to the casing to fail the casing at the deformation. A borehole system includes a borehole in a subsurface formation, a casing disposed in the borehole, and a casing modification and pulling tool disposed in the casing.