Antiscalant Trial at Kawerau Geothermal Field

Abstract

Scale formation is one of the main problems associated with the exploitation of water-dominated Geothermal fields. The deposition of calcium carbonate scale is a severe operational problem the Kawerau field in N necessitating annual workovers to cleanout the calcite in the casings. Investigations into alternative methods of scale control were conducted. The most promising appeared to be the use of scale inhibitors injected downhole via capillary tubing to a depth below the flash point. Laboratory tests were conducted to find an inhibitor that would not degrade at the high temperatures encountered the Kawerau field. Upon selection of a suitable chemical a field trial followed. Teething problems with the surface injection system has resulted in well rundown, however at the time of writing the run down was approximately half of that expected with no injection of inhibitor.