Evaluation of Scale Calculation Programs – Phase 2: Comparison of programs on the basis of real, multi-component reservoir brine systems
In the present project computer programs for scale calculations have been evaluated for their performance in describing the effects of the pressure, temperature, and pH-value. New models for calculation with the application of improved mathematical techniques and comparison with data from the literature are of particular interest for the purpose of the work.
During the second phase of the project, described by this report, the results of calculations performed with different scale programs used by E&P companies are to be compared and evaluated on the basis of specific reservoir brines. Even if data are not available for Solid-Liquid Equilibrium the predictions with the different software were performed.
Three programs for scale calculation were tested on real brines. The three programs were MultiScale from Petrochem, Scale-Chem from OLI, and Extended UNIQUAC from Technical University of Denmark. It was found that in the majority of cases the programs agreed on when scale was forming, but disagreed on the composition of the scale. The information given on the scale tendencies of the brines was insufficient to evaluate which of the three programs performed best. It was found that MultiScale was the least robust of the three programs, and several times failed to converge to a solution.
As it was stated in the conclusion of the report on phase 1 of this project, it is believed that a more reliable model for scale calculation can be developed.