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For A Medley Of Innovative Designs
DUET TECHNIQUE

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In many situations, the presence of the hole perturbes the measurement. One solution is to seal the hole, but that usually limits the access to perform measurements. The Duet approach allows one to seal the hole yet measure anytime and anywhere in the hole without disrupting the seal.

Potential Applications

Wicking liquid samples from fracture flows in horizontal holes in rock.

Monitoring holes beneath landfills where there is a concern that the presence of the open passage for monitoring may allow moisture condensation or drying to interfere with the collection of leachate samples.
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Collection of pore liquid samples in horizontal holes drilled beneath hazardous sites where the casing of the holes would interfere with the ability to collect pore liquid samples, yet the holes must be supported to maintain the access needed. This might be used with the LAHD method of horizontal drilling assistance before the casing is installed in the newly bored hole.

Installation and retrieval of a purge pump in a well requiring that the water be pumped from the well while a FLUTe™ liner is being everted into the hole. In this case, the first liner is the smaller liner containing a purge pump extending from its bottom end. Once the second liner is in place, the first liner is withdrawn by inversion with the purge pump and associated hose and cables.

As a means of installing an anchor at the end of a tortuous path to aid the installation of a larger, or heavier liner by the FLUTe™ Progressive Packer method using an exterior tether.

Actual Applications:

1. In 130 ft. long horizontal holes in the Yucca Mountain nuclear waste repository investigation site.
The holes were only 3 and 4 in. diameter, yet the sealing liners had gas sampling ports on them, and the second liners had annular absorbers for wicking of pore liquids without opening the hole in the flow field being measured. The first liner was left in place, and the second liners was installed and removed frequently to monitor the liquid composition.

2. In vertical holes at the Lawrence Livermore Natl. Lab. site 300. These were vertical holes with vadose gas sampling systems

A second 4 inch liner with annular absorbers was installed in a hole sealed with an 8 inch liner containing gas ports for discrete soil gas sampling at many levels.