mechanical drilling jar

MECHANICAL DRILLING JAR

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

 

Stroke     Model	Max upward jarring force	Max downward jarring force	Ex-plant upward jarring force	Ex-plant upward jarring force
QJZ121	490	270	360±25	200±25
QJZ159	630	360	470±25	270±25
QJZ165	630	360	470±25	270±25
QJZ197/ QJZ195	630	360	470±25	270±25
QJZ203	820	460	610±40	340±40

Table 2 Specification and performance parameters

Modle Item	QJZ121	QJZ159	QJZ165	QJZ197/195	QJZ203
OD   mm	121	159	165	197/195	203
Water hole     mm	45	57	57	71.4	71.4
Overall length(in locking position)  mm	6148	6505	6505	7075	7095
Up jar stroke   mm	198	150	150	150	153
Down jar stroke  mm	204	170	170	180	180
Connection  API	NC38	NC46	NC50	6 5/8REG	6 5/8REG
Tensile load;  KN	1100	1600	2000	2600	2800
Max working torque;  KN·m	15	25	25	30	35
Pumping area;   cm²	63	102	102	165	177

mechanical drilling jar