Jet Research Center Drill Collar Severing Tool P/N 101293224 Rev. K
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Jet Research Center, 8432 South I-35W, Alvarado, Texas, 76009-9775, USA
Telephone 1-817-761-2000; Toll Free 1-800-451-5403; Fax 1-817-783-5812; Website www.jetresearch.com
2. Description and Specifications
Jet Research Center’s (JRC) Drill Collar Severing Tools (DCST) are designed to sever drill
pipe, heavyweight drill pipe, and drill collars quickly and effectively. If pipe, collars, or bits
become stuck, it is recommended that the Severing Tool is shot above the “stuck” point so
that the free pipe can be recovered. These tools are also useful when restrictions preclude
the use of conventional drill pipe and casing cutters. Select the largest O.D. severing tool
that will pass through the minimum restriction in the drilling assembly. It is best to have the
appropriate size tool available in the event the restriction changes during the pipe recovery
operation.
The JRC DCST uses a unique dual end firing system, which simultaneously initiates both
ends of an explosive column. The detonation wave fronts collide at a centrally located
cartridge that shapes the high energy into effective severing action.
The Severing Tool incorporates safe arming procedures, utilizing detonator assemblies and
safety assembly equipment. An o-ring secures the detonator ground wire into a groove on
the mandrel, ensuring the detonator is properly grounded. A shunt plug maintains the
system electrically shorted during assembly as the detonator shunt wire is removed. A
protective holder encompasses the detonator, shielding the Explosive Supervisor, while the
electrical connection is made to the CCL. The DCST uses Resistorized detonators,
minimizing the chance of an accidental firing. The DCST can also be initiated using a Top
Fire RED detonator, providing additional safety enhancements when compared to
conventional Resistorized detonators.
These tools can perform in hostile environments. In standard tools, the explosives allow the
tool to function properly at temperatures up to 400°F (204°C) for one hour and at pressure
ratings up to 15,000 PSI (103 MPa). High Pressure (HP) accessories can be used to
achieve a pressure rating of up to 20,000 PSI (138 MPa). The DCST tool with HNS
explosive is rated for 460 F and one hour. In cooler temperatures HMX has better
performance values than HNS. The 2-1/8in High Pressure DCST can function at a pressure
rating of up to 26,000 PSI (179 MPa).
JRC’s severing tool utilizes a shock absorbing extension mandrel that minimizes damage to
uphole tools. The unique shock grooves dissipate the detonation shock waves transmitted
up the tool.
JRC recommends using centralizer tools to obtain maximum performance of the DCST.
These tools connect back to the wireline through widely available firing heads.
Avoid shooting a severing tool in or near the same place as a previous severance attempt,
as this may reduce the optimum function characteristics for severing the target. Six (6) feet
is a recommended minimum distance.
