Patent ID: 8205691
Filing Date: 2012-06-26
Classification: E21B

Abstract:
1. A down hole vibration dampener for dampening vibrations caused by drilling a well bore, the vibration dampener comprising: a hollow cylindrical housing having a lower connecting extent for connection to one part of a drill string; a splined mandrel extending longitudinally into the cylindrical housing and having an upper connecting extent for connection to another part of a drill string, the splined mandrel having a through bore; an upper seal structure located between the splined mandrel and an interior of the cylindrical housing adjacent the upper extent thereof; a floating, movable piston located between the splined mandrel and the interior of the cylindrical housing adjacent a lower extent thereof which, together with the upper seal structure defines a lubricant chamber for the vibration dampener; a vibration dampening structure located in the lubricant chamber which is formed between the interior of the hollow cylindrical housing and the splined mandrel, the vibration dampening structure being compressible longitudinally to absorb vibration and shock loads; wherein the vibration dampening structure is made up of a series of resilient rings formed of a polymeric material which are separated by a series of interspersed metal rings which give the resilient rings support and definition while being subjected to a load; wherein the resilient rings are formed of polyurethane; wherein the metal rings are formed of steel; and wherein the polyurethane rings are shaped and engineered in such a manner that when the set of polyurethane rings are subjected to a shock load, the metal rings will not touch one another except under maximum load circumstances.