Chapter 9

Impact Tools

Abstract

Simply stated, a jar is a delay mechanism. When installed in a fishing string and connected to a stuck object, a jar allows the operator the time required to pull and stretch the string. Using a hydraulic or oil jar, the pipe is pulled to a determined prejarring load while stretching the fishing string. The stretched drill string is held in tension, storing energy like a taut rubber band.

Keywords

Bidirectional hydraulic fishing jar

Bumper jars

Drilling jars

Fishing agitation tool

Intensifier jar

Jarring strings

Principles of jarring

Simply stated, a jar is a delay mechanism. When installed in a fishing string and connected to a stuck object, a jar allows the operator the time required to pull and stretch ...

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