SHOCK TOOL FOR DRILLSTRING

摘要

A shock tool for a drill string includes an outer tubular housing having female multi-spiral helical spline grooves disposed on an interior surface of the housing, and an inner tubular mandrel having a portion of an exterior circumferential surface with mating male multi-spiral helical splines. The inner tubular mandrel is telescopically and rotationally received in the outer tubular housing with the male splines received in the female spline grooves of the housing.

主权项

1. A shock tool for a drill string positionable in a wellbore, said shock tool comprising:
an outer tubular housing having female multi-spiral helical spline grooves disposed on an interior surface of the housing, said housing including an upper connector for coupling to the drill string and a lower connector for coupling to a spring housing; and an inner tubular mandrel having a portion of an exterior circumferential surface with male multi-spiral helical splines configured to mate with the female multi-spiral helical grooves of the outer tubular housing and at least a lower portion of the exterior circumferential surface of the mandrel not containing splines thereon, said inner tubular mandrel telescopically and rotationally received in the outer tubular housing with the male splines received in the female spline grooves of the outer tubular housing, said lower portion of the inner tubular mandrel without splines being received in the spring housing coupled to the outer tubular housing, said inner tubular mandrel having an axial fluid passageway for passage of drilling fluid supplied by the drill string through the mandrel, wherein said spring housing includes at least one disc spring disposed around the lower portion of the exterior surface of the mandrel not containing splines thereon and in an annulus between the mandrel and an inner surface of the spring housing, said disc spring having a predetermined biasing force that biases at least a portion of the mandrel outwardly through an axial opening in an upper end of the outer tubular housing.