WATER FLUTe™

Purpose

The Water FLUTe system is a multi level water sampling system. The general characteristics are as follows:

• Quickly emplaced from a shipping reel by eversion into the hole.
• Seals the entire borehole with a pressurized flexible liner of polyurethane coated Nylon fabric. The sealing pressure is provided by excess water head in the liner.
• Defines the sampling interval for each port with an exterior permeable surround called a "spacer."
• Draws the pore liquid into the central pumping system directly from the formation.
• Allows the water level for each port to be tagged from the surface
• Provides 1-3 gals, typically, from each port per stroke.
• All ports can be purged and sampled simultaneously.
• Is relatively easy to remove for repairs, replacement, etc…

Emplacement

The flexible liner is emplaced from a shipping reel. The top of the liner is attached to the surface casing (see the drawing, "Just Add Water") and the liner is then pushed down inside the casing a short distance. Water is added to the interior of the liner, driving the liner deeper into the hole, pulling the inside-out liner from the reel. The interior water pressure on the everting end of the liner is the driving force of the installation. Once the liner is fully extended in the hole, the geometry looks like that in the drawing below for a single port system.

The installation of a Water FLUTe is affected by the depth and diameter of the hole, the relative transmissivity of the hole, the depth to the water table, and the rate at which water can be supplied to fill the liner.

The installation procedure describes the difference when installing in a tight hole versus one that allows water to flow freely into the formation. If the hole is too tight to allow the liner to push the water into the formation, the water can be pumped from beneath the liner using a pump tube emplaced in the hole before the liner installation. In most situations, the Water FLUTe installation takes less than one day. Some installations have required less than one hour. A recent installation to 880 ft. required one day to complete.

Water FLUTe systems are usually installed in uncased core holes. Installations into multi-screened cased holes are also common. Varying hole diameters are accommodated. The Water FLUTe can be installed through smaller casing into larger open holes below the casing, or into "telescoped" casing.

The liner is completely heat welded without the use of any glues. The tubing is usually PVDF (polyvinylidene fluoride). Other types of tubing can be used.

Sample pumping system

The water flows from the formation into the spacer, through the port, into the tube which lies on the inside surface of the liner. The water flows from the port via the tube, to the bottom of the hole, and then upward through a steel check valve into the "U" shaped tube. The water rises in both legs of the U tube. In the larger (1/2"id) tube, the water level can be tagged from the surface. A gas pressure is applied to the large tube to drive the sample water through the second check valve to the surface. After purging the tubing, the sample water does not contact the drive gas. The large tube and pumping hardware are not everted into the hole, but simply lowered as a tubing bundle following the liner to the bottom. Note that all the water in the hole is isolated inside the liner.

The spacer, port, tubing and pump system shown are duplicated for each port. The liner is pressed against the hole wall by the excess head in the liner above the local water table.

Pressure transducers are often attached to the sampling tubing just below the first check valve to measure the head in the formation at the port location. The transducer is upstream of the valves in the pumping system. The pressure transducer can be calibrated to the head measured in the sampling system with a tag line.

Our experience with Water FLUTe systems now spans 10 years. Water FLUTe systems have been installed in 40 states in the U.S., and in Canada. More detailed descriptions and publications are available at Publications.

A typical installation of a 15 port system is shown in the photo. This installation took about 4 hrs., including the attachment of the surface hardware. The wellhead for the 15 port system with 15 pressure transducers is shown in the second photo. The simultaneous purging of all 15 ports took about 5 minutes.

15 Ports in 6" Hole to 330 ft.

Purging 15 ports simultaneously