Soroush Ahmadi

Water injection into the reservoirs is a technical method for increasing oil production. In this case, the sea water is usually used. For this reason, the mixture of injection and formation water can cause salt precipitation. The scale formation reduces the rock permeability and causes the failure of production equipment. In this study, the calcium carbonate and calcium sulfate scales were predicted in the mixture of injection and formation water using the OLI Studio program. In addition, the effect of temperature, pressure and mixing ratio on scale formation was determined. The results showed that the behavior of calcium carbonate and calcium sulfate formation is not the same. The calcium carbonate scale is reduced by increasing the percent of injection water in the mixture. However, the 60% injection water in the mixture caused the highest amount of salt formation. In addition, by increasing temperature, the scaling tendency of both salts is increased. Furthermore, the increase in pressure revues the scale formation. This effect for calcium carbonate was stronger than calcium sulfate.