DESIGN OF CO2-CH4 OPTIMUM COMPOSITION INJECTION AND MECHANISM USING HUFF AND PUFF METHOD AT L FIELD

• Main Author: Putu Gede Putra Arcana, I
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/40064
• Institution: Institut Teknologi Bandung

CO2 injection is one of the promising enhanced oil recovery (EOR) technology in the petroleum industry. This technology has been successfully applied in numerous countries by injecting CO2 either in miscible or immiscible condition and showing significant results. CO2 injection becomes more attractive since it does not only enhance oil recovery but also reduce the greenhouse gases which is favorable to overcome global warming. Other than CO2, CH4 also has been the main contributor to greenhouse gases. This study aims to determine the potential of using CO2 and CH4 as the injected fluid for enhancing oil recovery and study its oil recovery mechanisms since many studies show that CO2-CH4 is easily injected to the reservoir and can reduce the viscosity of the oil when they dissolve into the oil. Also, the optimum mixture composition is designed in this study to achieve the highest cumulative oil production. CO2-CH4 injection will be simulated at “L” field which has reservoir characteristic with low pressure, high temperature and light oil. Injection will be conducted using Huff and Puff method in immiscible condition because the minimum miscibility pressure is higher than fracture pressure of reservoir. Reservoir model that is generated based on “L” reservoir segment is used to forecast the production performance after CO2-CH4 injection using CMG GEM simulator. 900 Tons of CO2-CH4 mixture is injected for 30 days, with soaking time 14 days and production forecast is done for 180 days. The result of simulation shows that CO2-CH4 is proven to be the potential EOR at “L” field with additional 7.30 MSTB cumulative oil production from the base case without injection which only 425.82 MSTB. Moreover, using CO2-CH4 shows more significant result than only using CO2 with 4.42 MSTB additional cumulative oil. Other than increasing of reservoir pressure, oil swelling and oil viscosity reduction have been the most important mechanisms that improve the oil relative permeability and oil mobility which lead to higher oil recovery. Injected fluid composition of 90% CO2 and 10% CH4 demonstrates the most encouraging EOR mechanism which results in the highest cumulative production. Therefore, the most optimum injected fluid composition which is potential to enhance oil recovery is 90% CO2 combined with 10% CH4 with the following EOR mechanisms: reservoir pressure incremental, oil swelling, and viscosity reduction.