#TITLE_ALTERNATIVE#

• Main Author: ILMI (NIM : 12213055), FADILATUL
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/22026
• Institution: Institut Teknologi Bandung

About half of the world's oil reserves are in carbonate reservoirs (Rochl and Choquette, 1985) with 80-90% of them having oil wet properties (Chillingar and Yen, 1983). In an effort to increase oil recovery in the reservoir, one of the commonly used methods is EOR (enhanced oil recovery) by using chemical surfactant. Surfactants are organic compounds that can decrease the interfacial tension between non-wetting fluids and wetting fluids so as to improve the aggregation efficiency, and change the wettability properties of rocks that make the oil in the pores of rocks easier to push out. Laboratory studies aimed at determining surfactant solutions that can provide the most optimum recovery factor, as well as to know the effect of surfactant, co-surfactant, and core sample size effect on oil recovery in the case of heavy oil from field Z which is a carbonate reservoir. <br /> <br /> <br /> Laboratory studies performed consisted of three main processes: manufacture of artificial core carbonate, spontaneous imbibition test, and contact angle testing. In the manufacture of artificial cores, cores are made by mixing cement and carbonate (calcite / CaCO3) with a composition of 30% cement and 70% carbonate. Spontaneous imbibition tests were performed using water formation and six different types of solutions ie three variations of concentrations of 1%, 1.5%, and 2% for two variations in comparison between G-120 surfactants and co-surfactant T-120. In addition, experiments were also performed using core samples that have different sizes to serve as a comparison material. Testing of contact angle from artificial core aims to know the wetness of carbonate rock to formation water, field Z oil, and surfactant solution used. <br /> <br /> <br /> Based on the results of spontaneous imbibition experiments, it was found that a 2% concentration of surfactant solution with a G-120 and T-120 ratio of 9: 1 in the small cores resulted in the highest recovery factor with the fastest-gaining time compared to the other treatments. The greater the surfactant concentration, the greater the recovery factor obtained. In the experiment, the comparison of the number of different surfactants and co-surfactants used did not result a significant difference. This is because the function of the co-surfactant is simply as a stabilizer of the surfactant solution. Recovery factors generated on different size sample cores for the same surfactant solution yield different values. This is in addition to the volume of oil contained in the sample core is different, it takes time for the surfactant to reach the deepest pores. However, the amount of oil pressed for both cases tends to be the same. The larger the size of the core, the greater the displacement energy required by the surfactant and the lower the surfactant rate to fit into the overall core pores. Surfactants may be exhausted or energized to nourish the oil residing on the deeper core pores.