Carbon Capture Utilization and Storage (CCUS) is expected to be a key technology in reducing CO2 emissions and limiting global temperature rise below 2°C. This technology can directly capture CO2 from the air and store it in reservoirs (International Energy Agency, 2019). CCUS is predicted to reduce carbon emissions by up to 9% by 2050. Not only does CCUS store carbon emissions, but it can also be used to enhance the recovery factor in both oil and gas fields. In this context, CCUS is divided into two categories: Enhanced Oil Recovery (EOR) and Enhanced Gas Recovery (EGR). Numerous studies have been conducted to improve this technology. In Indonesia, the focus of research is more on oil fields than gas fields. One reason for this is the relatively lower economic attractiveness of increasing the recovery factor in gas fields. However, it is important not to overlook the potential application of CCUS technology in gas fields in the future.
This study aims to investigate the influence of injection parameters on CO2-EGR implementation using a compositional model. The parameters include injection rate, start time of CO2 injection, and location of perforations in relation to the increase in recovery factor and breakthrough time of injected CO2 in production wells. These parameters will be varied through continuous injection of pure CO2 using a synthetic reservoir model developed based on "TA" field data, which has a limestone lithology and is located in West Java Province, Indonesia. The model consists of four wells, including three production wells and one injection well. The Eclipse software is used for reservoir simulation, with a production period of 20 years starting from February 1, 2023, to February 1, 2043. The model is initialized using PETREL and PVTP software to develop the reservoir model.
The results of this study indicate that the investigated injection parameters play a role in breakthrough time and recovery factor. In terms of injection rate, lower injection rates, such as 5 MMSCFD, result in better displacement efficiency and longer breakthrough time compared to rates of 10 MMSCFD and 20 MMSCFD. The combination of these two factors leads to a higher CH4 recovery factor. Additionally, injection perforations in the aquifer zone yield a higher recovery factor compared to injections performed above the aquifer zone. Furthermore, the start time of injection results in a significant difference between injections in 2023 and 2037. In 2037, breakthrough occurred earlier. However, when considering the injection recovery factor in this year, it is relatively higher, and with this higher recovery factor, the produced CO2 is less compared to the injection in 2023.