Abstract: Provided is a drilling tool that includes a tubular body defining a longitudinal axial cavity extending therethrough. The tubular body also defines at least one radial guidance channel extending radially from the axial cavity through the tubular body. A cutter element is disposed in the at least one radial guidance channel and includes an internal surface inclined at an angle to a longitudinal axis of the tubular body. The drilling tool also includes a wedge element having an external surface configured to engage the internal surface of the cutter element and to direct the cutter element from a retracted position to an extended position as the wedge element moves from a first position to a second position.

Abstract: In accordance with an embodiment of the present invention, a drilling tool includes a tubular body defining a longitudinal axial cavity extending therethrough and defining at least one cutter element recess. The drilling tool also includes a cutter element at least partially disposed within the at least one cutter element recess and includes at least first and second cutting arms at least substantially disposed within the cutter element recess in a retracted position. The first and second cutting arms are operable to move from the retracted position to an extended position in which the first and second cutting arms extend at least partially beyond a periphery of the tubular body. The first and second cutting arms and the tubular body enclose a space when the first and second cutting arms are in the extended position.

Abstract: In accordance with an embodiment of the present invention, a drilling tool includes a tubular body defining a longitudinal axial cavity extending therethrough and defining at least one cutter element recess. The drilling tool also includes a cutter element at least partially disposed within the at least one cutter element recess and includes at least first and second cutting arms at least substantially disposed within the cutter element recess in a retracted position. The first and second cutting arms are operable to move from the retracted position to an extended position in which the first and second cutting arms extend at least partially beyond a periphery of the tubular body. The first and second cutting arms and the tubular body enclose a space when the first and second cutting arms are in the extended position.

Abstract: A bore hole underreamer is provided having a hollow body with a longitudinal axis, which has an external wall, at least two cylindrical bores provided through the external wall and whose axes are transverse to the longitudinal axis. Each of the bores have a cylindrical widening arm for widening the hole, which is arranged in the bore like a hydraulic piston, so as to be able to slide therein between an active position and an inactive position. The underreamer has a locking member which can occupy a locking position in which this member locks the arms in their inactive position, and which, when it is released, can leave the locking position under a thrust from at least one of the arms subjected to the pressure capable of pushing the arm into its active position.

Abstract: Provided is a bore hole underreamer, intended in particular for oil drilling. The underreamer has a hollow body and at least two cylindrical bores. The bores are distributed over the circumference of the hollow body and each bore contains a cylindrical widening arm. Each arm has a bladed cutting end disposed on the outside of the body that slides between active and inactive positions. Another end of each arm is disposed inside the body and receives fluid pressure for pushing the arm into the active position. The underreamer includes a locking member for locking the arms in their inactive position when the locking member is immobilized in the body in a releasable fashion in a locking position. When released, the locking member leaves the locking position under a thrust from at least one of the arms subjected to the pressure capable of pushing the arm into its active position.

Abstract: Provided is a bore hole underreamer in a terrestrial formation, intended in particular for oil drilling. The underreamer has a hollow body and at least two cylindrical bores. The bores are provided through an external wall of the body and have axes that are transverse to a longitudinal axis of the body. The bores are distributed over the circumference of the hollow body and each bore contains a cylindrical widening arm. Each arm has a bladed cutting end disposed on the outside of the body that slides between active and inactive positions. Another end of each arm is disposed inside the body and receives fluid pressure for pushing the arm into the active position. The underreamer includes a locking member for locking the arms in their inactive position when the locking member is immobilised in the body in a releasable fashion in a locking position.