REACTION VALVE DRILLING JAR SYSTEM

摘要

An apparatus and method for drilling is disclosed, including a drill string with at least one jar and one reaction valve. Drilling fluid flows through the reaction valve. The reaction valve is selectively throttled, which creates a differential pressure across the valve seat. The differential pressure creates an axial force that is transferred to the jar, which aids in cocking or firing the jar. In an embodiment, a reaction valve throttles downward fluid flow to create a downward compressional force on the jar, while in another embodiment, a reaction valve throttles upward fluid flow to create an upward tensile force on the jar. Upward and downward fluid flow may be alternatively throttled for alternately firing the jar upwards and downwards. A bypass valve may be included in the drill string for establishing a drilling fluid flow path when such may be otherwise obstructed by foreign matter in the wellbore.

主权项

1. A method for drilling a wellbore, comprising:
providing a drill string that includes a drill pipe, ajar, and a reaction valve disposed between said drill pipe and said jar, said jar including a mandrel that is slidingly received within a sleeve; flowing drilling fluid through said drill pipe and said reaction valve; and selectively throttling said drilling fluid by said reaction valve so as to create a differential pressure across said reaction valve to impart an axial force to said jar so as to urge said mandrel to move with respect to said sleeve.