The invention discloses a
shock absorber for a drilling tool in oil-gas drilling. The
shock absorber comprises a mandrel, wherein a spline and a fixed
piston are arranged on the mandrel; a spline outer cylinder is arranged on the spline, and the spline outer cylinder and the spline form an axial sliding pair; a plurality of damping channels are axially formed between the spline and the spline outer cylinder; the lower end of the spline outer cylinder is connected with a lower outer cylinder, and the upper end of the spline outer cylinder is sequentially connected with an upper outer cylinder,an upper seal joint and an
upper joint; the spline outer cylinder and the upper outer cylinder, the upper seal joint and the lower outer cylinder, the fixed
piston respectively form an upper annular cavity and a lower annular cavity at the periphery of the mandrel, and the two cavities are communicated through the damping channels; an oil injection
nozzle and a gas injection
nozzle are respectively formed on the spline outer cylinder and the upper seal joint in the radial direction; the oil injection
nozzle is communicated with the damping channels; the gas injection nozzle is communicated with the upper annular cavity through a gas injection annular channel; and a movable
piston is arranged in the upper annular cavity. The
shock absorber for the drilling tool in the oil-gas drilling integrates liquid, damping and gas shock absorption so as to avoid the fatigue failure of the drilling tool, and has the characteristics of high shock absorption performance, long service life, low manufacturing cost, simple structure, a few quick-wear parts, convenience of maintenance and the like.