Patent ID: 7677334
Filing Date: 2010-03-16
Classification: E21B

Abstract:
1. A method of drilling a well bore in a subterranean formation, said method comprising: drilling a well bore using a drill string comprising a drill bit, a positive displacement motor coupled to the drill bit, and a reverse thrusting tool positioned up hole from the motor, said drilling step including flowing a drilling fluid downhole through the drill string, the fluid exiting the drill string and flowing up hole through an annulus formed between the drill string and the well bore; axially shifting a piston assembly within an outer housing of the reverse thrusting tool from an extended position to a retracted position in response to a pressure differential between the drilling fluid flowing through the drill string and the fluid flowing through the annulus, wherein the piston assembly is biased toward the extended position by a spring biasing mechanism and where axial movement of the piston assembly is dampened by a sealed hydraulic fluid reservoir within the housing and presenting top hole and bottom hole portions, the top hole and bottom hole portions being connected by one or more channels having a total cross-sectional area that is less than the maximum cross-sectional area of either of the top hole and bottom hole portions; and said shifting step being performed without inducing relative rotation between the motor and the drill string where the piston assembly and the housing are configured with at least one inwardly extending collar from the housing having a plurality of splined sections and where the piston assembly also includes compatible splined sections adjacent to and intermeshing with the splined sections of the collar to prevent relative rotation between the motor and the drill string during axial shifting of the tool.