An encapsulated time-release corrosion inhibitor has proven to be highly effective against
CO2 corrosion in a field trial on 20 oil producing wells. The field trial ran from June 2005
through March 2006 in the southern San Joaquin Valley, California. The technology relies
upon a product delivery mode in which the corrosion inhibitor is released in a time-controlled
manner from the water-hydrocarbon interfacial region in the annulus of the well. This mode of
product delivery successfully afforded a near-continuous corrosion inhibitor treatment while
using a conventional batch-type application technique. A two-fold to seven-fold increase in
inhibitor usage efficiency was realized during this trial, as was a minimum two-month treatment
interval. The technology proved effective in both rod pumped and electric submersible
pumped (ESP) wells.