FPSO and Carbon Capture Storage Injection Unit Integration as an Offshore Decommissioned Facility Reutilization Alternative

Abstract The shifting global energy landscape puts the energy sector under increasing scrutiny to move towards sustainability and include efforts in its production cycle process, including the often-overlooked decommissioning phase. In 2018, Indonesia’s Ministry of Energy and Mineral Resources published a regulation stating that it is mandatory to have an abandonment and site restoration (ASR) strategy for each facility operating in the country. The regulation leads to studies of decommissioning strategy, by combining methods and finding more sustainable solutions, such as reutilizing the facility for other purposes. The study utilizes the Floating Production Storage and Offloading (FPSO) Unit as one of the facilities that will be decommissioned. The 285-metre-long FPSO has two existing systems to produce crude oil and LPG, equipped with a single mooring buoy and 3-phase risers. In line with the national initiative, a reutilization plan for the decommissioned facilities is being developed through the integrated FPSO-CCS system. The research aimed to develop a system that meets the required technical, economic, and regulatory framework. The FPSO-CCS system is designed and simulated with constraints from the existing FPSO. The system is divided into three: the capture system, storage system, and injection system. Each system is designed based on a literature review and existing constraint, simulated using a chemical process simulator, and visualized in a process flow diagram and layout using a computer-aided design software. The capture system is planned to use monoethanolamide (MEA) as a solvent for a post-combustion carbon capture system from the 15 MW gas-fired generator. The storage system is planned to have the CO2 liquefied to maximize the volumetric efficiency with the Linde-Hampson principle and could receive liquid CO2 via receiving risers, acting as a carbon hub. The injection system fully reutilizes the existing injection module on the FPSO, which was previously used to inject gas and water as part of the enhanced oil recovery process. All systems are simulated using the Peng-Robinson equation of state, which is commonly used because of its properties’ similarities to CO2. The result shows that the capture system can reduce the CO2 emissions by up to 84% or 177.282 tonnes/day. The captured CO2 is liquified at -28 °C. Celsius and 15 bar and injected in its supercritical phase at 34 °C. Celsius and 79 bar. The plant has a storage capacity of 371.8 tonnes CO2 and a maximum injection capacity of 2.92 MMSCFD. The research is expected to provide an integrated FPSO-CCS system that is technically, economically, and environmentally viable. The novelty of this research is to provide solutions for FPSO decommissioning and reutilization by integrating FPSOs and a carbon capture and injection facility to bridge the industry’s needs and environmental sustainability.