HYDRAULIC JAR DEVICE

摘要

A hydraulic jar device for use in through-tubing drilling and fishing operations which consists of an elongate tube having an upper hammer sub, a kelly cylinder and a hydraulic cylinder with central restrictor secured therebelow. A lower sub connects to the bottom end of the hydraulic cylinder. The sliding interior components are an upper mandrel secured to an anvil sub which, in turn, is fastened to an axial plunger, all of which are slidable down within the elongate tube. A metering ring retained on the plunger interacts with the central restrictor of the hydraulic cylinder to control force effected up and down jars that occur when the mandrel strikes the hammer sub on the down stroke, and when the anvil sub strikes the hammer sub bottom on the up stroke.