Working Principle

The hydraulic shock absorber is connected between the drill bit and drill collar. During drilling operation, the torque is transferred from top of drill string to the absorber’s mandrel. The spline will then transfer the torque through the spline outer barrel, oil cylinder and lower sub to drive and rotate the drill bit.

Weight on bit is the total amount of downward force exerted on the drill bit from the top of the drill string. Significant weight on bit is required for the drill bit insert to efficiently drill into the formation to break rocks into pieces. The drilling mud is fed through the bore of drill pipes and collars into the mandrel of shock absorber and finally ejected into the well bottom through the lower sub bore of the shock absorber.

During drilling, because of the uneven well bottom condition and structure of the cone bit, the different force components mentioned above are exerted on the drill bit and drill string resulting in severe vibration. The hydraulic shock absorber will thus absorb the vibrational energy by means of compressing and deforming the compressible fluid under pressure. The shock absorber can reduce the vibration and impact load on the drill tools.