DRILL STRING AXIAL VIBRATION ATTENUATOR
First Claim
1. A drill string axial vibration attenuator, comprising:
- an elongate sealed chamber adapted for being immovably affixed within a pipe of a drill string; and
an elongate stabilizer mass resiliently supported within the sealed chamber.
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Accused Products
Abstract
The drill string axial vibration attenuator (10) is installed in the bottom hole assembly (BHA) of a drill string to attenuate axial and torsional vibrations of the drill string. The vibration attenuator (10) includes a massive elongate stabilizer (14) installed in a sealed chamber (12) that is, in turn, rigidly installed within the BHA of the drill string. Clearance between the inner wall of the chamber (12) and the stabilizer (14) is provided to preclude frictional interference therebetween. The stabilizer mass (14) is supported from below by a compression spring (18) and a shock absorber or damper (24) at the top to allow movement of the mass (14). The stabilizer (14) substantially reduces or eliminates axial and coupled torsional vibration of the drill string when the mass of the stabilizer (14), the rate of the spring, and the damper stiffness are properly configured.
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Citations
20 Claims
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1. A drill string axial vibration attenuator, comprising:
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an elongate sealed chamber adapted for being immovably affixed within a pipe of a drill string; and an elongate stabilizer mass resiliently supported within the sealed chamber. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A drill string axial vibration attenuator, comprising:
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an elongate sealed chamber adapted for being disposed concentrically within a pipe of a drill string, the chamber having an outer surface and an inner surface, the chamber outer surface and the inner surface of the pipe defining a toroidal passage therebetween, the chamber having an upper end and a lower end; a first resilient member extending downward within the chamber from the upper end; a second resilient member extending upward within the chamber from the lower end; and an elongate stabilizer mass disposed concentrically within the sealed chamber, the stabilizer mass being attached to and suspended between the first and second resilient members, the stabilizer mass having an outer surface, the stabilizer mass outer surface and the chamber inner surface defining a toroidal stabilizer clearance volume therebetween, the stabilizer being free of contact with the inner surface of the chamber. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A drill string with axial vibration attenuation, comprising:
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a plurality of elongate pipes connected end-to-end to define a drill string, the drill string having an upper end and a lower end; a drill bit mounted on the lower end of the drill string; a bottom hole assembly located in the lower end of the drill string; and at least one attenuator mounted in the bottom hole assembly, the attenuator having; an elongate sealed chamber mounted coaxially within the bottom hole assembly, the chamber being annularly spaced from the bottom hole assembly, the chamber having an upper end and a lower end; a vibration damper mounted at the upper end of the chamber; a spring mounted at the lower end of the chamber; and an elongate mass having an upper end attached to the damper and a lower end attached to the spring, the elongate mass being annularly spaced from the chamber and resiliently move upward and downward to counteract axial forces occurring during drilling operations, thereby preventing and reducing axial vibration of the drill string. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification