Decarbonization of energy supply to offshore oil & gas production with post-combustion capture: A simulation-based techno-economic analysis

Abstract

Low-carbon-emissions FPSO (Floating, Production, Storage, and Offloading) designs are developed and compared, using process simulation in HYSYS, and an original economic analysis approach. FPSO units with power-intensive operations (e.g., fields with high gas-to-oil ratio) are the focus of the study. Three designs are evaluated: Case A considers a floating natural-gas-combined-cycle power unit with post-combustion CCS (Carbon Capture and Storage) connected to an existing FPSO. Case B.1 retrofits a CCS unit downstream of a conventional FPSO with simple-cycle power generation. B.2 adds a more efficient combined cycle to B.1. The removed CO2 is injected for enhanced oil recovery. Marginal abatement cost is investigated for oil prices of 60/80/100 USD/bbloil and recovery of 0.0/1.5/3.0 bbloil/tCO2 injected. The added weights to topsides are 4,326t (A), 2,762t (B.1) and 3,445t (B.2). CO2 intensity (kgCO2/boe) is reduced from 6.92 in the conventional design to 0.74 (A-B.2) and 0.92 (B.1). The marginal abatement cost of B.1 and B.2 are alike, approaching zero at 1.5 bbloil/tCO2 oil recovery. Taking technical retrofitting challenges aside, Case B.1 is the most cost-effective alternative. Cases A and B.2 have a slightly better environmental performance than B.1, but B.2 presents a superior economic performance and lower operational risks compared to A.