US 11,814,959 B2
Methods for increasing the amplitude of reciprocal extensions and contractions of a shock tool for drilling operations
Sean Matthew Donald, Spring, TX (US); Andrew Lawrence Scott, Houston, TX (US); Yong Yang, Spring, TX (US); and Roman Kvasnytsia, Edmonton (CA)
Assigned to NATIONAL OILWELL VARCO, L.P., Houston, TX (US)
Filed by National Oilwell Varco, L.P., Houston, TX (US)
Filed on Nov. 30, 2021, as Appl. No. 17/537,743.
Application 17/537,743 is a continuation of application No. 15/849,471, filed on Dec. 20, 2017, granted, now 11,220,866.
Claims priority of provisional application 62/513,760, filed on Jun. 1, 2017.
Claims priority of provisional application 62/536,955, filed on Dec. 20, 2016.
Prior Publication US 2022/0090449 A1, Mar. 24, 2022
This patent is subject to a terminal disclaimer.
Int. Cl. E21B 7/24 (2006.01); E21B 17/07 (2006.01)
CPC E21B 7/24 (2013.01) [E21B 17/07 (2013.01)] 9 Claims
OG exemplary drawing
 
1. 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, the method comprising:
(a) selecting the shock tool, wherein the shock tool has a central axis and an axial length, wherein 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, and wherein 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:
(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), wherein the second annular piston is axially spaced from the first annular piston, wherein 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), wherein the second amplitude of reciprocal axial extension and contraction is greater than the first amplitude of reciprocal axial extension and contraction, wherein a floating annular piston is disposed about the mandrel within the outer housing, wherein the floating annular piston is axially positioned uphole of the first annular piston and the second annular piston, wherein the floating annular piston is configured to move axially relative to the mandrel and the outer housing, and wherein the floating annular piston sealingly engages the mandrel and the outer housing.