Abstract: An underreamer for increasing a diameter of a wellbore. The underreamer may include a body having an axial bore extending at least partially therethrough. An electromagnetic activation system may be disposed at least partially within the bore of the body. A valve may be disposed within the bore of the body and coupled to the electromagnetic activation system. The valve may include a mobile element and a static element. The mobile element may be coupled to the electromagnetic activation system and move from a first position where the mobile element obstructs fluid flow through the valve to a second position where the mobile element permits fluid flow through the valve. A cutter block may be movably coupled to the body and move radially-outward as the mobile element moves from the first position to the second position.

Abstract: An underreamer for increasing a diameter of a wellbore. The underreamer may include a body having an axial bore extending at least partially therethrough. An electromagnetic activation system may be disposed at least partially within the bore of the body. A valve may be disposed within the bore of the body and coupled to the electromagnetic activation system. The valve may include a mobile element and a static element. The mobile element may be coupled to the electromagnetic activation system and move from a first position where the mobile element obstructs fluid flow through the valve to a second position where the mobile element permits fluid flow through the valve. A cutter block may be movably coupled to the body and move radially-outward as the mobile element moves from the first position to the second position.

Abstract: An underreamer for increasing a diameter of a wellbore. The underreamer may include a body having an axial bore extending at least partially therethrough. An electromagnetic activation system may be disposed at least partially within the bore of the body. A valve may be disposed within the bore of the body and coupled to the electromagnetic activation system. The valve may include a mobile element and a static element. The mobile element may be coupled to the electromagnetic activation system and move from a first position where the mobile element obstructs fluid flow through the valve to a second position where the mobile element permits fluid flow through the valve. A cutter block may be movably coupled to the body and move radially-outward as the mobile element moves from the first position to the second position.

Abstract: A tool with a hydraulic lock mechanism may include a body defining a flow tube and a chamber. An expandable member may be coupled to the body. A first valve may be located between the chamber and the flow tube to control the flow of fluid into the chamber from the flow tube. A second valve may located between the chamber and an external environment to control the flow of fluid from the chamber into the external environment. The first and second valves may trap fluid within the chamber to maintain the tool in an active position. A piston may be connected to the expandable member and may move in response to pressurization of the chamber. At one position, the piston may cause the expandable member to extend to a radially outward position. At another position, the piston may cause the expandable member to retract to a radially inward position.

Abstract: A section milling device may include a plurality of rotatable arms that each include one or more cutting members. The rotatable arms may be rotated between a retracted position and an extended position. When rotated to the extended position, the rotatable arms may be locked or substantially limited in their movement by one or more hydraulic pistons. The rotatable arms may be held at a predetermined angle during milling operations.

Abstract: An underreamer for increasing the diameter of a bore. The underreamer includes a substantially cylindrical body. A mandrel may extend axially through the body. One or more cutter blocks are movably coupled to the body. A ratio of a height of the cutter block to a diameter of the body is between about 0.35:1 and about 0.50:1.

Abstract: An underreamer for increasing a diameter of a wellbore. The underreamer may include a body having an axial bore extending at least partially therethrough. An electromagnetic activation system may be disposed at least partially within the bore of the body. A valve may be disposed within the bore of the body and coupled to the electromagnetic activation system. The valve may include a mobile element and a static element. The mobile element may be coupled to the electromagnetic activation system and move from a first position where the mobile element obstructs fluid flow through the valve to a second position where the mobile element permits fluid flow through the valve. A cutter block may be movably coupled to the body and move radially-outward as the mobile element moves from the first position to the second position.

Abstract: A section milling device may include a plurality of rotatable arms that each include one or more cutting members. The rotatable arms may be rotated between a retracted position and an extended position. When rotated to the extended position, the rotatable arms may be locked or substantially limited in their movement by one or more hydraulic pistons. The rotatable arms may be held at a predetermined angle during milling operations.

Abstract: A tool with a hydraulic lock mechanism may include a body defining a flow tube and a chamber. An expandable member may be coupled to the body. A first valve may be located between the chamber and the flow tube to control the flow of fluid into the chamber from the flow tube. A second valve may located between the chamber and an external environment to control the flow of fluid from the chamber into the external environment. The first and second valves may trap fluid within the chamber to maintain the tool in an active position. A piston may be connected to the expandable member and may move in response to pressurization of the chamber. At one position, the piston may cause the expandable member to extend to a radially outward position. At another position, the piston may cause the expandable member to retract to a radially inward position.

Abstract: An underreamer for increasing the diameter of a bore. The underreamer includes a substantially cylindrical body. A mandrel may extend axially through the body. One or more cutter blocks are movably coupled to the body. A ratio of a height of the cutter block to a diameter of the body is between about 0.35:1 and about 0.50:1.