Techniques for removing a tubular from a wellbore include running a downhole tool on a downhole conveyance into a wellbore formed from a terranean surface into a subterranean formation; activating a piston sub-assembly to repeatedly move pistons to contact a portion of a casing installed in the wellbore to at least de-bond a cement layer installed between the portion of the casing and the subterranean formation from the portion of the casing; activating a cutting sub-assembly to move a cutting blade to cut through the portion of the casing adjacent the de-bonded portion of the cement layer; activating a hanger sub-assembly to move a set of slips into contacting engagement with the cut portion of the casing; and running the downhole tool on the downhole conveyance out of the wellbore with the cut portion of the casing engaged with the set of slips.

Techniques for removing a tubular from a wellbore include running a downhole tool on a downhole conveyance into a wellbore formed from a terranean surface into a subterranean formation; activating a piston sub-assembly to repeatedly move pistons to contact a portion of a casing installed in the wellbore to at least de-bond a cement layer installed between the portion of the casing and the subterranean formation from the portion of the casing; activating a cutting sub-assembly to move a cutting blade to cut through the portion of the casing adjacent the de-bonded portion of the cement layer; activating a hanger sub-assembly to move a set of slips into contacting engagement with the cut portion of the casing; and running the downhole tool on the downhole conveyance out of the wellbore with the cut portion of the casing engaged with the set of slips.

A downhole tool, for removing a restriction in a well tubular metal structure having a wall and an inner diameter, has a tool axis and a tool body having a first part and a second part, an electrical motor arranged in the first part for rotating a rotatable shaft, and a core bit arranged in the second part and having a first end connected with the rotatable shaft and a second end having a cutting edge. The second part of the downhole tool further includes a locator for locating the rim section, the locator being rotable with the core bit until the locator locates the rim section and a threshold value is reached.

A downhole tool, for removing a restriction in a well tubular metal structure having a wall and an inner diameter, has a tool axis and a tool body having a first part and a second part, an electrical motor arranged in the first part for rotating a rotatable shaft, and a core bit arranged in the second part and having a first end connected with the rotatable shaft and a second end having a cutting edge. The second part of the downhole tool further includes a locator for locating the rim section, the locator being rotable with the core bit until the locator locates the rim section and a threshold value is reached.

A method and apparatus to move an object in an open hole section of a wellbore. A bottom hole assembly including a downhole pulling tool and fishing device is described. The downhole pulling tool includes an open hole anchor to allow location of the downhole pulling tool in the open hole section of the wellbore so as to reduce the operating distance between the downhole pulling tool and the fishing device. An embodiment in which a cut section of tubular is removed from the open hole section is described. A casing cutter may also be located in the bottom hole assembly to cut the tubular on the same trip in the well as removing the cut section of tubular.

A method and apparatus to move an object in an open hole section of a wellbore. A bottom hole assembly including a downhole pulling tool and fishing device is described. The downhole pulling tool includes an open hole anchor to allow location of the downhole pulling tool in the open hole section of the wellbore so as to reduce the operating distance between the downhole pulling tool and the fishing device. An embodiment in which a cut section of tubular is removed from the open hole section is described. A casing cutter may also be located in the bottom hole assembly to cut the tubular on the same trip in the well as removing the cut section of tubular.

A casing removal system includes a flow diversion valve. The flow diversion valve includes a flow switch that engages an upper end of an inner casing. When the flow switch engages the upper end of the inner casing, the flow diversion valve opens and at least a portion of the fluid flow through the casing removal system exhausts to the annulus. The remaining fluid flow below the flow diversion valve is insufficient to operate a mud motor that drives a casing cutter. In other embodiments, when the flow switch is not engaged with the inner wall of casing, the flow diversion valve prevents fluid flow to components that are downhole of the valve and when the flow switch is engaged with the inner wall of casing, the flow diversion valve allows for fluid flow to components that are downhole of the valve.

A casing removal system includes a flow diversion valve. The flow diversion valve includes a flow switch that engages an upper end of an inner casing. When the flow switch engages the upper end of the inner casing, the flow diversion valve opens and at least a portion of the fluid flow through the casing removal system exhausts to the annulus. The remaining fluid flow below the flow diversion valve is insufficient to operate a mud motor that drives a casing cutter. In other embodiments, when the flow switch is not engaged with the inner wall of casing, the flow diversion valve prevents fluid flow to components that are downhole of the valve and when the flow switch is engaged with the inner wall of casing, the flow diversion valve allows for fluid flow to components that are downhole of the valve.

A thru-tubing recover string (10) and method of moving a stuck object (14) in tubing in a well (16). A bottom hole assembly (22) is connected to a work string and includes a first (32) and a second tool (34), each tool configured to apply a force to the object in order to move the object (14), the first force being an impulse force, the second force being a static force, and the tools being operable independently so that an operator can apply either force in the event that application of one type of force on the object fails to move the object. Embodiments are described for the first tool (32) being a hammer tool or a jar and the second tool being a pulling tool such as a jack. The invention finds application in removing stuck objects such as plugs or actuating elements on tools such as sliding sleeves in production tubing.

A thru-tubing recover string (10) and method of moving a stuck object (14) in tubing in a well (16). A bottom hole assembly (22) is connected to a work string and includes a first (32) and a second tool (34), each tool configured to apply a force to the object in order to move the object (14), the first force being an impulse force, the second force being a static force, and the tools being operable independently so that an operator can apply either force in the event that application of one type of force on the object fails to move the object. Embodiments are described for the first tool (32) being a hammer tool or a jar and the second tool being a pulling tool such as a jack. The invention finds application in removing stuck objects such as plugs or actuating elements on tools such as sliding sleeves in production tubing.