关键词: 海上油田, 高含CO2伴生气, 压缩机, 超临界态

Abstract: Many offshore oilfields see the associated gas with the CO₂ content when they are brought under development. The associated gas is unable to be used as fuel once the CO₂ content exceeds 30 to 40 percent. In addition, the high-CO₂ gas is transmitted over a long distance at high risks and costs. To fulfill the carbon peak and carbon neutrality objective, one of the offshore oilfields planned to pressurize the CO₂ associated gas to the supercritical state for re-injection and burial. The dry-gas re-injection scheme was recommended after comparison was made between the dry-gas and wet-gas re-injection schemes. The design of compression process was determined on the basis of analyzing a series of key factors, such as compressor model, driving mode, configuration, skid structuring method and design requirements. Finally, two reciprocating compressors were recommended to pressurize the high-CO₂ associated gas to a supercritical state through three-stage compression. Meanwhile, the high-CO₂ associated gas between the second and third stages was drawn out of the kid to enter the molecular sieve skid for dehydration. The skid structure of the two compressors were optimized to substantially reduce occupation of the platform space.