CHEMICAL STIMULATION IN NEAR-WELLBORE GEOTHERMAL FORMATIONS: SILICA DISSOLUTION IN THE PRESENCE OF CALCITE AT HIGH TEMPERATURE AND HIGH pH

Abstract

Chemical stimulation was investigated in the laboratory as an alternative to hydraulic stimulation for increasing well injectivity and near-wellbore permeability in geothermal reservoirs. Calcite and silica dissolution rates were measured in a high-temperature flow reactor in the presence of a chelating agent NTA and at high pH. Results indicate that calcite and silica dissolution rates each increase with pH and flow rate. The mineral dissolution processes within the laboratory flow reactor were simulated using a 1-D TOUGHREACT reactive transport model.