Geothermal injector KKP-GT-02 lost its injectivity after being in use for about one year. An investigation, by means of wireline, proved that the well was plugged with lead. Because a regular clean-out operation using coiled tubing was no option, WEP developed a chemical solution for this problem. A “cocktail”, not being harmful to the casing / well integrity was developed by WEP in order to dissolve lead scaling.
The cocktail was spotted at the obstruction down in the well through a workstring run by a crane. The operation was carried out successfully and injectivity in the well has been fully restored. The geothermal doublet is operational again.
Prevention of lead precipitation in geothermal wells:
WEP also worked out a method that prevents precipitation of lead. This method is now in use at the wells in Koekoekspolder and is (will be) closely monitored to keep the doublet running for many years. An additional advantage of the prevention method is that the well is better protected against corrosion. Corrosion is the major cause of lead precipitation; No corrosion, No lead issues!