CO₂驱是提高低渗透油藏采收率最有效的技术手段之一，但注入的CO₂会引发原油中沥青质沉淀，导致储层渗透率下降并改变储层的非均质性。为明确不同压力条件下沥青质差异化沉淀对低渗透储层非均质性的影响，以吉林油田某低渗透油藏为研究对象，通过CO₂长岩心驱替实验，明确了不同压力下的CO₂驱替特征，同时结合原油及岩心性质测试结果，分析不同压力条件下驱替前后原油沥青质含量及储层性质变化，进一步明确了沥青质沉淀的分布规律。结果表明：非混相条件下，原油采出程度较低，仅为55.11%，沥青质沉淀随驱替距离的增加呈现先增加后减小的趋势，CO₂主要驱替大孔喉原油，沥青质沉淀也主要发生在高渗区域内，从而抑制了储层非均质性；混相条件下，原油采出程度较高，达81.84%，沥青质沉淀随驱替距离的增加而增加，CO₂能够驱替小孔喉原油，沥青质沉淀发生在高渗及低渗区域，但低渗区域受到的影响大，储层非均质性进一步加强。

CO₂ flooding is one of the most effective technical means to improve the recovery of low permeability reservoirs. However, the injected CO₂ will cause asphaltene precipitation in crude oil, resulting in the decrease of reservoir permeability and the change of reservoir heterogeneity. In order to clarify the effect of asphaltene differential precipitation on the heterogeneity of low permeability reservoirs under different pressure conditions, a low permeability reservoir in Jilin Oilfield was taken as the research object. Through the CO₂ long core displacement experiment, the CO₂ displacement characteristics under different pressures were clarified. At the same time, combined with the test results of crude oil and core properties, the changes of crude oil asphaltene content and reservoir properties before and after displacement under different pressure conditions were analyzed, and the distribution law of asphaltene precipitation was further clarified. The results show that under immiscible conditions, the degree of crude oil recovery is low, only 55.11%. The asphaltene precipitation increases first and then decreases with the increase of displacement distance. CO₂ mainly displaces the large pore throat crude oil, and the asphaltene precipitation also mainly occurs in the high permeability area, thus inhibiting the reservoir heterogeneity. Under miscible conditions, the degree of crude oil recovery is high, up to 81.84%. Asphaltene precipitation increases with the increase of displacement distance. CO₂ can displace small pore throat crude oil. Asphaltene precipitation occurs in high permeability and low permeability areas, but low permeability areas are greatly affected, and reservoir heterogeneity is further strengthened.