Residual Oil Zones (ROZ) form when oil has leaked or migrated from a reservoir trap through geological time, leaving a zone of immobile oil. Here we assess the feasibility of ROZ production with CO₂ flooding, in a North Sea oil field for the first time. We identify a hydrodynamically produced ROZ, with an oil saturation of 26%, in the Pierce Oil Field of the Central North Sea and adapt established recovery factors for Carbon Dioxide Enhanced Oil Recovery (CO₂ EOR) from onshore fields, to estimate oil resource and CO₂ storage potential. Our mid case results show that CO₂ utilisation increases commercial reserves by 5–20% while storing 15 M t CO₂. Based on our calculations CO₂ EOR can produce low carbon intensity crude oil from a mature basin and could store more CO₂ than is released from the production, transport, refining and final combustion of oil.

当石油在整个地质时间内从储集层中泄漏或迁移时，就会形成剩余油区（ROZ），从而留下一个不流动的油区。在这里，我们首次评估了在北海油田用CO ₂驱油生产ROZ的可行性。我们在中北海的Pierce油田中发现了水饱和度为26％的水力法生产的ROZ，并采用已建立的采收率来提高陆上二氧化碳的二氧化碳采收率（CO ₂ EOR），以估算石油资源和CO _2的储存潜力。我们的中间结果表明，在储存15 M t CO _2的同时，CO _2的利用可将商业储藏量提高5-20％。根据我们的计算，CO ₂EOR可以从一个成熟的盆地中生产出低碳强度的原油，并且可以储存比从生产，运输，精炼和最终燃烧中释放的更多的CO ₂。