Validation and application of physical and numerical methods for scaling predictions

Laboratory and numerical simulations that predict scale formation are useful tools for integrated reservoir management. However, their Validation under reservoir conditions prevailing during oil recovery by water injection still is relatively weak. In this study, physical and thermodynamic numerical simulations of scale formation are validated, and the thermodynamic model application is extended with kinetic calculations. 34 experiments covering a broad range of conditions were conducted. The numerical simulations corresponding lo ail these conditions were also performed It was experimentally observed that Ca+2 and Mg+2 concentrations decrease. Numerical codes predicted these final experimental concentrations of Ca+2 with a <15% difference and Mg+2 with a <20% difference, and showed carbonate precipitation. Main factor that seems to determine the observed behavior is the decrease in the Ksp of carbonate minerals with increasing temperature from 25 to 100 degrees C. Water monitoring campaign was started, based on previous results. Comparing the output of code with the average composition of the 5 samples collected monthly, it was demonstrated that codes are able to predict Ca+2 and Mg+2 and scale formation in the field, if both, pressure and temperature conditions and, initial water composition are known. Taking into account current water injection rates in lake Maracaibo basin, a precipitation forecast was made of 460 tons of carbonate per day. Kinetic calculations showed that at the current injection depths, and flow rates in Lake Maracaibo basin, most of the carbonates should precipitate deep into the formation.