二氧化碳驱替与埋存一体化数值模拟

目前数值模拟无法同时计算CO₂在油、气、水相中的分配及水相中溶解CO₂对储层物性的影响。针对该问题,应用CO₂驱替与埋存一体化数值模拟,通过耦合油气两相闪蒸、CO₂在水中的溶解和溶蚀作用,同时模拟CO₂在油气水三相中的分配、溶解CO₂对储层物性的影响、CO₂驱油与埋存全过程。研究结果表明:CO₂溶于地层水后形成碳酸溶蚀岩石,导致储层渗透率增加,作用时间越长,溶蚀效果越明显;CO₂在水相中的溶解和溶蚀作用对累计产油量和CO₂埋存量均有影响,在研究CO₂驱替与埋存问题时需要同时考虑溶解和溶蚀作用,才能反映生产实际。对濮城油田沙一下储层进行数值模拟研究,证明了CO₂驱替与埋存一体化数值模拟方法准确。该研究对CO₂驱油与埋存项目的方案设计和CO₂埋存潜力评价具有借鉴和指导作用。

Integrated Numerical Simulation of Carbon Dioxide Displacement and Sequestration

At present, numerical simulations cannot calculate the distribution of CO₂ in oil, gas, and water and the effect of CO₂ dissolved in water on the physical properties of the reservoir. In response to this problem, the innovative application of the integrated numerical simulation of CO₂ displacement and sequestration can simulate the distribution of CO₂ in oil, gas and water, the effect of dissolved CO₂ on sequestration, and the whole process of CO₂ displacement and sequestration on the basis of the coupled oil-gas flash evaporation and the solution and dissolution of CO₂ in water. It was found in the study that CO₂ dissolved in formation water developed into carbonic acid dissolved rock, leading to an increase in reservoir permeability, and the longer the action duration, the more obvious the dissolution effect; the solution and dissolution of CO₂ in the water affected the cumulative oil production and CO₂ sequestration. In the study of CO₂ displacement and sequestration, it was necessary to consider both the solution and dissolution effects in order to reflect the actual production. The numerical simulation study was conducted in the Lower Sha 1 reservoir in Pucheng Oilfield, and proved that the integrated numerical simulation method of CO₂ displacement and sequestration is accurate. This study can become certain reference and guidance for scheme design of CO₂ displacement and sequestration project and the evaluation of CO₂ sequestration potential.