General overview

Model QJZ Mechanical Drilling Jar is a kind of mechanical drilling jar for downhole stuck freeing. It integrates the up jar and down jar and can free the dragged and stuck accident during the drilling operation. It is an ideal tool for directional well and deep well drilling.

Compared with hydraulic or hydro-mechanical drilling jar, the “QJZ” mechanical drilling jar has the following advantages:

a)  It can be directly used to jar upward and downward to free the stuck while drilling. It is unnecessary to pull out the string and then use the fishing jar to free the stuck. b) It is convenient to adjust the jarring load before tripping in. The jarring load will remain the… same when working down hole.

c) The spline system of the drilling jar doesn’t have the phenomenon of torque loosen, so it is suitable for directional well drilling.

d) The changing of the hydraulic oil quality in the inner chamber will not affect the jarring effect due to the application of mechanical structure. All working parts are in the hydraulic oil while performing, minimizing the degree of wear and tear, also avoiding accident and effectiveness lost by preventing material and cement outside from coming inside.

e) There is a balance piston design in the drilling jar to balance the pressure inside and outside.

f) Except the drilling jars smaller than 4 3/4”, all other drilling jars have the tapered thread on the outside bowl, facilitating the assembly and disassembly operation.

g) Its unique structure makes the jar more accurately transmit the torque, more available for drilling deviated well.

Specifications

Table 1 Adjustable Jarring Force of “QJZ” Mechanical Drilling Jar 

Unit: KN

Table 2 Specification and performance parameters

mechanical drilling jar