VAN RUTH® PRESSURE GROUTING TOP PACKER
The VAN RUTH® PRESSURE GROUTING TOP PACKER (PGTP) formally our CWTP now redisigned is used to pressure grout through rods, the packer and into the hole. The PGTP has a non return valve and can be used on it's own in blind holes for unstable ground formations, fault zones and permeability testing. For zone isolation or off bottom testing the PGTP is used together with the CWBP, multiple zones can be tested and/or cemented while pulling rods.
PRESSURE GROUTING: The PGTP is placed by lowering the rods to depth and pumping the PGTP at a moderate speed. The PGTP will mechanically lock in the drill hole upon leaving the rods. With the rods still engaged on the PGTP's upper seal/s, pumping pressure build up on the PGTP will set the packer and eventually eject the slips retaining cup allowing grout to pass through the packer's non return valve and into the formation.
MULTIPLE ZONES: isolation or testing can be achieved while pulling rods. Multiple PGTPs and or CWBPs may be set with a single pull of rods out of the hole. An open rod string is run to the deepest test location and a PGTP is pumped down and used to perform a permeability test at this bottom location (grouting can also be performed if needed). The rod string is then positioned below the second fault or testing zone and a CWBP is pumped down and set to act as a bridge in the drill hole. The rod string is further raised above the fault zone and another PGTP is pumped down to test the second zone and so on... As only one rod trip is required for multiple zone testing and cementing, no time is lost due to tripping the rods. The time savings using this method are considerable.
COLLAR REPAIR: The same PGTP and CWBP combination can again be used to repair collar deterioration or when lost circulation has occurred: Lowering rods to below the deterioration and setting a CWBP in a stable hole location will act as a bridge and will preserve the hole conditions below. The PGTP can now be used to pressure grout and stabilise the uphole conditions. Only the newly grouted and stabilised uphole section of the hole need be redrilled.
PRESSURE BELOW: PGTP Where up hole slippage is of concern while cement is curing, adding the HD PLUG will provide an opposing mechanical lock to the assembly. Please note that the PGTP and HD PLUG must be set separately.
A vented hoisting plug should be used for withdrawing the rodstring while the rods are being withdrawn at moderate speeds only. Where a HD PLUG is not being used, suction above the PGTP may have a tendency to pull it up the hole. This effect is further increased if grease, mud or soft sections in the hole seal against the rod string.
See also: Sub Set Grouting Packer.
Construction: Drillable Aluminium and Urethane.
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