Abstract: A downhole tool may include a generally hollow piston having a trigger element extending therefrom, the piston configured to slide along an axial cavity extending through a tubular body of the tool. The trigger element may move from a first position where the trigger engages a support on the body and the piston is fixed, to a second position where the trigger disengages and the piston is released. The tool may also include a generally tubular relief sleeve releasably coupled with the piston using a shear pin, while the trigger element is in the first position, and disposed between the trigger and an extension of the piston, to allow the sleeve to slide between the trigger and the extension after shearing of the pin. The piston, sleeve and pin may be configured to allow the sleeve to release from the piston in response to the shearing of the pin.

Abstract: A downhole tool may include a generally hollow piston having a trigger element extending therefrom, the piston configured to slide along an axial cavity extending through a tubular body of the tool. The trigger element may move from a first position where the trigger engages a support on the body and the piston is fixed, to a second position where the trigger disengages and the piston is released. The tool may also include a generally tubular relief sleeve releasably coupled with the piston using a shear pin, while the trigger element is in the first position, and disposed between the trigger and an extension of the piston, to allow the sleeve to slide between the trigger and the extension after shearing of the pin. The piston, sleeve and pin may be configured to allow the sleeve to release from the piston in response to the shearing of the pin.

Abstract: A downhole tool may include a generally hollow piston having a trigger element extending therefrom, the piston configured to slide along an axial cavity extending through a tubular body of the tool. The trigger element may move from a first position where the trigger engages a support on the body and the piston is fixed, to a second position where the trigger disengages and the piston is released. The tool may also include a generally tubular relief sleeve releasably coupled with the piston using a shear pin, while the trigger element is in the first position, and disposed between the trigger and an extension of the piston, to allow the sleeve to slide between the trigger and the extension after shearing of the pin. The piston, sleeve and pin may be configured to allow the sleeve to release from the piston in response to the shearing of the pin.

Abstract: The invention relates to a bottom tool comprising a tubular body (1) with an axial chamber, a hollow piston (8) capable of sliding in said axial chamber, and an actuation device including a trigger member (14) connected to the hollow piston and capable of displacement from a hollow-piston immobilisation position to a withdrawal position in which it releases the hollow piston, a detent tubular sleeve (16) of the trigger member connected to the hollow piston by at least one shearing pin (17), and means for temporarily blocking the detent tubular sleeve that generates a hydraulic pressure rise on the tubular sleeve with a shearing of said at least one shearing pin and the sliding of the detent tubular sleeve in a release position in which the trigger member is capable of displacement into its withdrawal position.

Abstract: An assembly for sidetracked drilling in a wall of a borehole previously drilled or cored in a formation includes a guide element and an expansible device fixed to the front end of the guide element operable to be selectively expanded by an actuation means. A sidetracking channel is formed in the guide element in alignment with an internal space, upstream of the expansible device in the direction of advance. A longitudinal cavity is formed in the guide element parallel to the longitudinal axis and arranged to allow passage from the internal space to the actuation means of the expansible device. Within the internal space of the guide element, an external tube of the core barrel includes a core bit fixed to the front end of the external tube and arranged to slide, after having been released, in the internal space and in the sidetracking channel and then progress to the formation.

Abstract: An assembly for sidetracked drilling in a wall of a borehole previously drilled or cored in a formation includes a guide element and an expansible device fixed to the front end of the guide element operable to be selectively expanded by an actuation means. A sidetracking channel is formed in the guide element in alignment with an internal space, upstream of the expansible device in the direction of advance. A longitudinal cavity is formed in the guide element parallel to the longitudinal axis and arranged to allow passage from the internal space to the actuation means of the expansible device. Within the internal space of the guide element, an external tube of the core barrel includes a core bit fixed to the front end of the external tube and arranged to slide, after having been released, in the internal space and in the sidetracking channel and then progress to the formation.