Prediction of deposition of calcium sulfate scale under down- hole conditions

Abstract

Compared are different methods of calculating the deposition of calcium sulfate (CaSO//4) compounds in water and sodium chloride (NaCl) brines. The termodynamic method has been improved by including the effects of the complicated down- hole plase equilibria, thus eliminating errors made by previous investigators. The new method, although still limited in application, appears to be more reliable. Results of the study indicate that prediction of scale deposition from chemical analyses of field water alone is likely to be misleading if temperature and pressure conditions are not properly considered.