Hydraulic Impact Apparatus and Methods

摘要

A hydraulic jar coupled between opposing first and second portions of a downhole tool string. The hydraulic jar includes a housing comprising a shoulder protruding radially inward from an internal surface of the housing, a shaft disposed within the housing, a piston fixedly positioned about the shaft and fluidly sealed against the shoulder, and a pressure relief device. The housing and the shaft move axially relative to each other and the shoulder axially interposes first and second portions of an annulus formed between the shaft and the housing. The pressure relief device controls fluid flow from the first annulus portion to the second annulus portion based on a pressure of the fluid in the first annulus portion relative to a set pressure of the pressure relief device.

主权项

1. An apparatus, comprising:
a hydraulic jar coupled between opposing first and second portions of a downhole tool string,
wherein the hydraulic jar comprises:
a housing comprising a first longitudinal bore extending therethough, wherein a substantial portion of the first longitudinal bore has a first diameter;a mandrel having a second longitudinal bore extending therethough, wherein an annulus formed around the mandrel within the first longitudinal bore comprises a fluid, and wherein the housing and the mandrel are moveable relatively in first and second axially opposing directions;an electrical conductor electrically coupling the first and second portions of the downhole tool string and extending through the second longitudinal bore;a piston carried with the mandrel and fluidly sealing against a reduced diameter section of the housing, wherein the reduced diameter section has a second diameter that is substantially less than the first diameter of the first longitudinal bore, and wherein the reduced diameter section collectively interposes first and second longitudinally offset portions of the annulus; anda pressure relief device controlling fluid communication from the first annulus portion to the second annulus portion based on a pressure of fluid in the first annulus portion and an electrical status of the electrical conductor.