Perpustakaan Digital ITB

Carbon Capture and Storage (CCS) is a promising approach to reducing carbon dioxide (CO?) emissions by injecting CO? into underground formations, where it can be safely stored over long periods. During the injection process, CO? undergoes significant changes in pressure and temperature, which can impact well integrity. One critical phenomenon is Joule-Thomson cooling, where a substantial temperature drop occurs as CO? expands through flow restrictions such as valves or narrow tubing sections. Understanding this cooling effect is essential to ensure safe and reliable operation, particularly around sensitive components like the Subsurface Safety Valve (SSSV), which may be exposed to rapid thermal fluctuations. This study utilizes the dynamic multiphase flow simulator to analyse the relationship between shut-in time, start-up time, and SSSV closing time during a blowout, and how these variables affect CO? temperature drop at the SSSV. The findings indicate that an optimum shut-in period of 2 hours minimizes the Joule-Thomson effect at the SSSV. In contrast, both start-up and SSSV closure during blowout should be executed rapidly to reduce the extent of CO? cooling. The specifications of the SSSV are also critical for accommodating the conditions during injection. A Tubing Retrievable Subsurface Safety Valve (TRSSSV) is considered more suitable for injection wells due to its superior long-term performance and reduced throttling effect. A pressure rating of 5,000 psi and a minimum operating temperature of –31°C are recommended, based on the expected pressure loads and extreme transient temperature conditions. Additionally, it is recommended that the SSSV be installed at a depth between 1,501 ft and 2,253 ft to avoid potential hydrate formation and to ensure proper valve closure during operation.