Torque control device for a downhole drilling assembly

摘要

This invention relates to a torque control device for a downhole drilling assembly. The torque control device is adapted for connection to a drill bit, and has an outer sleeve and an inner shaft, the outer sleeve being movable longitudinally relative to the inner shaft. The torque control device also has a cylinder, a piston located within the cylinder, and a controller to control the volume of the cylinder. Changing the volume of the cylinder causes relative longitudinal movement between the outer sleeve and the inner shaft. The controller can receive inputs from a torque sensor and/or an accelerometer in order to determine if a threshold torque has been exceeded. Alternatively the controller can comprise a rotary valve which automatically responds to torque in the assembly.

主权项

1. A torque control device for a downhole drilling assembly, the downhole drilling assembly comprising a drill bit and connected componentry which are adapted to rotate during drilling, the torque control device being adapted for connection to the drill bit, the torque control device including an outer sleeve and an inner shaft, the outer sleeve and the inner shaft being respective parts of the connected componentry which are adapted to rotate during drilling, the outer sleeve being movable longitudinally relative to the inner shaft, the torque control device having a cylinder, a piston located within the cylinder, and a controller to adjust the volume of the cylinder, the volume of the cylinder being adjustable whilst the outer sleeve and the inner shaft are rotating.