Mechanical filter
AssigneeThomson Marconi Sonar S.A.S.
InventorsJohn Michael Beresford, Paul Andrew Crowther
Life of this patent
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Abstract
A drill string assembly containing a section of tube with a first end. The first end directly, mechanically links a drill pipe to a drill bit and transmits rotational forces from the drill pipe to the drill bit during drilling. A spring is connected to the section of tube at a point remote from the first end of the section of tube. A mass is connected to the spring such that the mass can vibrate on the spring in an axial direction relative to the section of tube and drill string. The value of the mass and the stiffness of the spring being selected such as to cause them to act as a mechanical filter and damp longitudinal compression waves at a predetermined frequency of frequency band and received at the first end of the section of tube.
Claims13
A drill string assembly comprising:
- a section of tube, with a first end, wherein the first end directly, mechanically links a drill pipe to a drill bit and transmits rotational forces from the drill pipe to the drill bit during drilling;
- a spring connected to the section of tube at a point remote from the first end of the section of tube;
- and
- a mass connected to the spring such that the mass can vibrate on the spring in an axial direction relative to the section of tube and drill string, the value of the mass and the stiffness of the spring being selected such as to cause them to act as a mechanical filter and damp longitudinal compression waves at a predetermined frequency of frequency band and received at the first end of the section of tube.
Dependencies are inferred from the claim text.