Study of the effect of cycle time and WAG ratio of CO2 miscible water alternating gas (WAG) injection in field X

• Main Authors: Wahyuningrum, Citra, Fathaddin, Muhammad Taufiq, Nugrahanti, Asri, Kasmungin, Sugiatmo, Mardiana, Dwi Atty, Omar, Esaim Mustafa Abrahim
• Format: Conference Proceeding
• Language: English
• Subjects: Carbon dioxide; Cycle ratio; Cycle time; Efficiency; Enhanced oil recovery; Gas injection; Miscibility; Moisture content; Surface tension; Water flooding; Water injection
• ISSN: 0094-243X; 1551-7616
• DOI: 10.1063/5.0126844

Miscible CO2 injection is one of the enhanced oil recovery (EOR) methods by expanding the volume of oil, reducing viscosity and density, reducing interfacial tension, and extracting oil into the CO2 phase which can reduce the mobility ratio of the oil. The miscible CO2 injection method chosen is the Water Alternating Gas (WAG) method. The WAG method is the latest technology to increase sweeping efficiency during injection, minimize the amount of CO2 that must be used, reduce the mobility ratio of oil and slow down the breakthrough that generally occurs in the continuous CO2 injection method. The purpose of this study was to determine the effect of cycle time and the optimal WAG ratio on the CO2 miscible WAG injection method to obtain the highest recovery factor value in field X. Cycle time and WAG ratio are important parameters in WAG CO2 injection because cycle time is the transition time between water injection and CO2 gas injection and WAG Ratio is the ratio of the amount of water injection rate and CO2 to be injected into the reservoir. If too much water is injected, the microscopic efficiency will decrease, while if too much CO2 gas is injected, it will cause a low sweep efficiency. Research methodology with three-dimensional simulation software CMG compositional. The results obtained from the CO2 miscible WAG injection method are the most optimal slug size using 2 PV with an inverted five spot well pattern, in a cycle time of 90 days (3 months), and the optimal WAG ratio using a 1:3 ratio (injection water rate 20,036).