An Investigation and Determination of Different Salinity, Ion Type and pHs Effect on Fine Migration in Sandstone Reservoirs

Low salinity water (LSW) injection and alkaline flooding are two common enhanced oil recovery (EOR) methods. Although these methods have a lot of advantages, they could cause some formation damages. One of the main problems during LSW injection and alkaline flooding is fine migration. Fine migration might reduce reservoir permeability or produce and damage well facilities. Ionic strength and pH are two main factors that could control fine migration in these EOR methods. In this paper, the effect of four salts NaCl, KCl, CaCl2, and MgCl2 was studied as an ion strength parameter on fine migration. To investigate the effect of pH, four pH of 6.5, 8, 10, and 12s was considered. The results showed that the presence of salts decreases the amount of fine migration compared to distilled water injection, and divalent salts have a better performance than monovalent salts. The results also showed that the simultaneous presence of divalent ions in the injection fluid increases the intensity of fine migration. Furthermore, studies on pH’s effect indicate that increasing the injection fluid’s pH causes the more fine migration. Zeta potential measurements prove that the potential of fine particles surfaces increases by raising fluid pH. As a result, the repulsive forces between fine particles are greater at the higher pH which causes to increase fine migration.