Performance of Calcium Carbonate Inhibition and Neutralization Systems for Production Wells at the Miravalles Geothermal Field

Abstract

Power generation at the Miravalles geothermal field currently depends on the utilization of 21 systems for inhibition of calcium carbonate scale, as well as 3 acid-neutralization systems, in the field’s production wells. The performance of the inhibition and neutralization systems is described in this document. The Miravalles field has been producing electric energy since March 1994, supplying steam to Unit 1 (55 MW), a wellhead unit (5 MW) installed in 1995, Unit 2 (55 MW) in 1998, and Unit 3 (29 MW) in 2000, with brine being supplied to Unit 5 (19 MW, a binary plant) since 2004. The calcium carbonate inhibition systems (in use since 1994) as well as the neutralization systems (since 2000) have been used successfully in the production wells that supply steam and brine to the generating units. Experience has indicated that the injection (at depth) of an appropriate dosage of inhibitor makes it possible to produce the geothermal wells with little or no deposition, at lower cost than performing periodic mechanical cleanouts.