The Small-Diameter Well Quandary

The small-diameter well quandry often confronts geoscientists and engineers who, in an effort to be "cost-effective", often install small-diameter borings and wells.   The small-diameter borings and wells, by themselves, do not pose a quandary.   However, making measurements and obtaining samples often does.

Some Solutions

Water level measuring devices and oil/water interface meters do not always fit readily down small-diameter wells.  The measuring probes and tapes also tend to cling to small-diameter well casings, especially when they are moist.   These problems can be minimized by using the right equipment.  Water level and oil/water interface devices with small-diameter probes and narrow tapes can be used.   For example, Heron Instruments water level instruments come with probes smaller than 1/2-inch in diameter.    Sometimes the small probe, because it is lighter in weight has a problem making its way down the well.   This may be overcome, in some cases, by adding extra weights.

Some Help from Heron

Heron will add extra weight to the end probe upon request.   Also, upon request, Heron will attach a smaller 3/8-inch (9.5 mm) end probe to a Dipper-T instrument in place of the standard 5/8-inch (16 mm) where smaller diameter is required.   Sufficient weight on the probe is critical for the tape to move down the well properly.

Heron has developed a special small-diameter instrument (the Heron Skinny Dipper) for special situations.   This rugged instrument is designed for use in small-diameter wells (microwells) and piezometers.  The tape on the skinny dipper is a narrow 0.24 inch x 0.133 inch (6.2 mm x 3.4 mm).  The probe is 0.25 inch (6.25mm) diameter stainless steel. This small-diameter profile allows use of the skinny dipper in tubes as small as 0.375 inch (9.5mm) internal diameter.