Use of a geared bit to reduce drill string vibrations without affecting performances

Drilling deep holes into the earth’s crust is required to extract natural resources such as crude oil and has also been utilized in the geothermal energy industry to extract heat. Drilling these wells is carried out using long slender pipes, and due to the destructive nature of the drilling operation, these pipes undergo torsional, lateral, and axial vibrations. Increasing the stiffness of the drill pipe would reduce torsional vibrations; however, considering the length, this is not economically feasible. Another approach is to increase the apparent stiffness by reducing the torque transmitted through the drill pipe. This is achieved by increasing the rotational speed of the drill pipe and using a reduction gearbox at the bit to maintain the original bit rpm. Similar methodologies have been used in the automotive driveshaft to reduce torsional deflection. The proposed bit has a tri-cutter design due to the gearbox, and this arrangement also eliminates the tendency of bit whirl. Reducing torsional vibrations also enables drillers to increase weight-on-bit (WOB) to control axial vibrations. Reduction in drill string vibration would increase the durability and reduces unexpected failure.

Faculty Supervisor:

Geoff Rideout

Student:

Partner:

Springboard Atlantic Inc.

Discipline:

Engineering

Sector:

Mining; Oil and Gas; Energy and Utilities

University:

Memorial University of Newfoundland

Program: