Scale Inhibition in Geottiermal Operations — Experiments with Dequest 2060 Phosphonate in Republic's East Mesa Field

摘要

Two calcium carbonate (CaCO3) scale inhibition tests have been performed at Republic Geothermal, Inc.'s (RGI's) East Mesa wells #16-29 and #56-30. The first test at well #16-29 could not be finished due to downhole pump problems. However, two inhibitor concentration runs were completed and a third run started before the pump failed. A follow-up test at well #56-30 was completed according to the original plan. Typical power plant conditions (i.e., pressure and temperature drops, flow conditions) were simulated by using test loops (pipe diameters of eight inches at well #16-29 and twelve inches at well #56-30) and field separators.nUntreated East Mesa brine exhibits a calcium carbonate scale tendency as soon as the pressure is dropped below 75 psig. The uninhibited brine from well #16-29 formed a maximum scale thickness of 0.5 inch in an eight inch TD pipe after a 92.75 hour test run at an average production rate of 375,000 lb/hr. The brine from well #56-30 formed a maximum scale thickness of 1.25 inches in a twelve inch ID pipe after a 104 hour test run at an average production rate of 722,000 lb/hr.