Methods for increasing the amplitude of reciprocal extensions and contractions of a shock tool for drilling operations

Abstract

A method for increasing an amplitude of reciprocal axial extensions and contractions of a shock tool configured to induce axial oscillations in a drillstring during drilling operations includes (a) selecting the shock tool. The shock tool has a central axis and an axial length. The shock tool includes an outer housing, a mandrel telescopically disposed within the outer housing, and a first annular piston fixably coupled to the mandrel. The shock tool has a first amplitude of reciprocal axial extension and contraction at a pressure differential between a first fluid pressure in the outer housing and a second fluid pressure outside the outer housing. In addition, the method includes (b) fixably coupling a second annular piston to the mandrel of the shock tool and increasing the axial length of the shock tool after (a). The second annular piston is axially spaced from the first annular piston. The shock tool has a second amplitude of reciprocal axial extension and contraction at the pressure differential between the first fluid pressure in the outer housing and the second fluid pressure outside the outer housing after (b). The second amplitude of reciprocal axial extension and contraction is greater than the first amplitude of reciprocal axial extension and contraction.