储层非均质性对自生CO2调驱效果的影响

为了研究海上油田储层纵向非均质性对自生CO₂调驱效果的影响规律，分别建立了12组层间非均质物理模型和3组层内非均质物理模型，利用驱油实验考察了自生CO₂调驱对层内非均质性、层间非均质性和渗透率级差等因素的适应性。实验结果表明：在各层渗透率都相同的条件下，自生CO₂调驱技术对层内非均质模型提高采收率的幅度可达27.40%～31.03%，而对层间非均质模型提高采收率的幅度仅为17.38%～22.05%，说明CO₂调驱技术受层间非均质性的影响更大；对于中—低渗透层相同层间非均质模型，渗透率级差越大，自生CO₂调驱提高采收率的效果越好；用渗透率均值来表征层间非均质性的影响，自生CO₂调驱提高采收率的幅度随渗透率均值的增大呈现出先增大后减小的趋势。矿场试验结果表明，自生CO₂调驱技术对海上油田具有良好的增油效果，应用前景广阔。

Influence of vertical heterogeneity of reservoirs on in-situ CO2 profile control and flooding effects

In order to study the influence of vertical heterogeneity of offshore oil reservoirs on in-situ CO2 profile control and flooding effect,12 groups of inter-layer heterogeneity models and 3 groups of in-layer heterogeneity models were established respectively.The adaptability of in-situ CO2 profile control and flooding to in-layer heterogeneity,interlayer heterogeneity and permeability ratio was investigated by displacement experiments.The results show that under the condition of the same permeability of each layer,the recovery improvement range of insitu CO2 profile control and flooding on the in-layer heterogeneity models can reach 27.40%-31.03%,while that on the inter-layer heterogeneity models was only 17.38%-22.05%,indicating that the CO2 profile control and flooding technology was mainly affected by inter-layer heterogeneity.For inter-layer heterogeneity models with same medium and low permeability layer,the higher the permeability ratio,the better the enhanced oil recovery effect of in-situ CO2 profile control and flooding.Permeability mean value were used to characterize the effect of inter-layer heterogeneity.Enhanced oil recovery of in-situ CO2 profile control and flooding showed a trend of increasing and decreasing with the increase of permeability mean value.Field tests showed that in-situ CO2 profile control and flooding technology had good oil-increasing effect in offshore oilfields and had broad application prospects.