CO₂ breakthrough vs. gas-processing facilities: Qualitative appraisal

This study describes how gas-processing facilities are impacted by injected CO₂ returning to surface through production streams, with the goal to improve profitability of the enhanced-oil-recovery (EOR) project by postponing the expenses of handling returning CO₂. In the short term, mixing the incremental oil that has a higher CO₂ content with the remaining production streams of lower CO₂ content will allow the existing gas-processing facilities to accommodate the returning CO₂. In the long term, the compression capacity should be increased and acid gas should be enriched with H₂S before being fed to sulphur-recovery units. Another alternative is to isolate the impact of CO₂ on the existing facilities by using an exclusive separation train, reinjecting the associated gas (or the acid part of it) and sending the sweet part to existing facilities for natural-gas-liquid (NGL) recovery-provided that the capacity is available. Enrichment units can be used to extract H₂S from acid gas for sulphur recovery in existing units, provided that the capacity is available, while pure CO₂ can be injected. Cryogenic fractionation will be required to separate mixtures of ethane and CO₂.