| Title | EVALUATION OF CORROSION INHIBITORS FOR ACIDIC GEOTHERMAL WELLS |
|---|---|
| Authors | M.A. Todd, L. Muller |
| Year | 2018 |
| Conference | New Zealand Geothermal Workshop |
| Keywords | Corrosion inhibitor, acid well, corrosion |
| Abstract | As enhanced geothermal systems (EGS) grows so too is the need for dealing with acid brines. Already in Indonesia, Philippines, Turkey, Japan and Europe some plants cannot utilize their geothermal resources due to the acidity and aggressiveness of the brine. Geothermal wells can be sometimes acidic due to high levels of carbon dioxide (CO2) and hydrogen sulfide (H2S). Often the pH can drop to 5, and in some cases to 3, under these conditions. This acidic, often saline, water is very corrosive. This led to the investigation of corrosion inhibitors under these highly aggressive conditions in order to assist the wider use of existing and future acidic geothermal resources. Corrosion inhibitors were evaluated in a series of screening tests. Initial screening was conducting using 5 minute visual tests at room temperature. This process quickly eliminated a number of obviously poor inhibitors. Next, jar test screening was conducted for 18 hours at pH 7 and 95 oC. This further reduced the number of acceptable inhibitors. Finally the leading candidates were evaluated at acidic pH. The promising inhibitors were also evaluated using several electrochemical techniques. |