Hydraulic Drilling Jar Open Hole DST Tool Drill Stem Testing Tools
Operation
Introudction of Hydraulic Jar / Big John Jar
The hydraulic jar is used in DST tool string as a safety tool in
well testing service. The hydraulic jar in Halliburton is named Big
John Jar, and can help free the stuck tools to reduce the rig time.
The hydraulic jars are available in 3 7/8 inch and 5 inch, and the
working pressure reaches to 15000 psi, the jars are used in cased
hole, slim hole and openhole drill stem testing service.
Technical parameter of Hydraulic Jar
| No | Specification | 3 7/8” | 5 " |
| 1 | O.D. | 99.1mm | 127.5mm |
| 2 | Bore Diameter | 32mm | 57mm |
| 3 | Length | 1574mm | 1695mm |
| 4 | Working pressure | 105Mpa | 105 Mpa |
| 5 | Stroke | 254mm | 254mm |
| 6 | Torque strength | 9.4KN.m | 22 KN.m |
| 7 | Service | H2S,NACE MR0175(>175oF) |
| 8 | Working temperature | -29oC+204oC |
| 9 | Connection thread | 3 1/8 8N | 3 7/8CAS. BXP or 3 1/2 IF.BX
|
How to operate the hydraulic jar during the downhole operation
* Maximum pull to trip
The maximum pull of the hydraulic jar to trip is the pull place on
the jar to cause it to trip. Any pull greater
than the maximum pull will fatigue the impact mandrel and
eventually lead to weakening it.
* Tensile limit of the hydraulic jar
The tensile limit is the maximum pull that can be placed on the
jars. Using the tensile limit will add a fatigue
cycle and reduce the life of the jars. While jarring, the tensile
limit may be applied several times an hour, but we do not recommend
that it be used repeatedly.
Operation of the hydraulic jar
The temporary resistance that powers the jar is provided by a
hydraulic time-delay system. Resistance is released when the
metering sleeve inside the jar moves into a bypass section of the
outer case. This action allows the special hydraulic oil to bypass
rapidly.
The time delay required to release the temporary resistance varies
in relation to the weight of the pull. For example, a light pull
requires more time for release than a hard pull. When tools below
the jar are stuck, a steady pull applied to the jar creates an
upward impact blow to the string. The jar can be re-cocked when the
string is set down.
Techcore Oil Tools expertise in manufacture of the Drill Stem
Testing Tools for more than Ten years, the professional Reserch and
Development (R&D) department improves the advanced technology
in design of the Drill stem testing tools for well testing service.
The drill stem testing tools are applied in cased hole, open hole
and slim hole, the main DST tool string includes RTTS packer,
circulating valve, safety joint, select tester valve, omni valve,
hydraulic jar, shock absorber, RD safety circulating valve, high
pressure retrievable packer with bypass, IPO valve, tubing string
test valve, and so on.
We approach every client’s enquiry with meticulous attention to
technical specifications, and a high level of appreciation for
their urgency.
Welcome to contact us for more information about our company and
the oil tools!
