Laboratory and Field Testing of Calcium Carbonate Scale Inhibitors

Abstract

Scale formation is one of the main problems in the exploitation of water dominated fields. In the Italian ones, characterized by a high CO2 pressure in the reservoirs, calcium carbonate precipitates in the production wells and surface equipment. Among the various methods for carbonate scale control (mechanical or chemical cleaning, downhole pumps, injection of CO2, acids, scale inhibitors), the latter has appeared to be the most promising. Laboratory tests were conducted for preliminary screening of the commercial products and to verify their effectiveness by means of a simulated "geothermal circuit". Field experimentation then followed (at Cesano and Latera), with injection of the products at wellhead and downhole using a specially designed injection system. The best results were obtained with the organic phosponates. The economic impact on the value of the final product is relatively low.