Calcium carbonate scaling control in geothermal well PV8 in Sao Miguel, Azores, combining chemical inhibition and mechanical reaming

Abstract

The formation of calcium carbonate (calcite) is a major scaling problem that occurs in geothermal fields around the world, leading to a quick decline in well output and impacts on power plant production. There are several methods that can be used for the prevention of calcite scaling and the rehabilitation of affected production wells. In Ribeira Grande geothermal field, in addition to prevention by injection of chemicals to inhibit scaling, reaming is used in well PV8. Currently at Ribeira Grande field, the main method used in reaming involves quenching and cooling the well prior to the operation and this affects well performance. This study pursues the development of a method that involves reaming the calcite without cooling the well by allowing it to flow. The main focus of this report is the design of equipment (kind of a Stripper) and work procedures to enable mechanical cleaning of calcium carbonate deposits inside a well, discharging the deposits to a silencer.