  Water hammers commonly are observed at wellheads and often are considered a
potential hazard that should be avoided. Nevertheless, there are a few
situations in which water hammers provide very valuable information about a
well. A comprehensive data-acquisition and analysis system has been developed
by Brouard Consulting and Ecole Polytechnique. One potential application of
that system is determining the depth of an interface between two fluids. This
application has been tested successfully at the Manosque field. It is
demonstrated here how this low-cost and non-intrusive system can be accurate
and allows practical, real-time measurements.
