INVESTIGATION THE EFFECT OF WETTABILITY ALTERATION DUE TO IMMISCIBLE CO2 INJECTION IN SANDSTONE RESERVOIR

• Main Author: ANDHIKA, LUTFI
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/22935
• Institution: Institut Teknologi Bandung

Carbon Dioxide (CO2) injection in the formations is one proposed method for enhance oil recovery and also isolating the CO2 from the atmosphere. CO2 will dissolved in the formation brine along the injection. Dissolved CO2 forms an acidic environment which could modify the petrophysical properties. One of phenomenon that could happen due to this interaction is alteration of wettability during CO2 injection that affecting the production performance. <br /> <br /> <br /> The observation of this phenomenon was perfomed by measuring contact angle between oil and several buffer solutions on thin section of sandstone sample. The use of the solution was meant to approach product of CO2 solubility in water that could occur in reservoir condition, evaluated by Henry constant. Then, the result of the measurement was simulated in an inverted 5-spot injection model. This was conducted to evaluate the effect altered wettability in oil recovery performance using experimental result. The simulation scenarios, were water injection, water + CO2 injection without wettability alteration, and water + CO2 with wettability alteration. <br /> <br /> <br /> Interpretation of contact angle test indicated that lowering the pH value of buffer solution induced wetting phase of rock to become more water wet, this caused by a great amount of H+ ion that was contained in lower pH. The ion will make the fluid more dispersed on the surface of the rock as it has generally a negative charge. Furthermore, the running of simulation showed that scenario of injecting CO2, equipped with the wettability alteration, resulted in an increase in oil recovery compared to other cases. This was happened as the alteration of wettability will change the relative permeability, thus reducing residual oil of the model. Thus, the small increase of recovery is caused by the attributed of rock in experimental study which has been a water wet condition. <br /> <br /> <br /> It can be concluded from this study that the dissolved CO2 in water/brine could increase oil recovery in CO2 injection due to wettability alteration. <br />