页岩储层CO2驱沥青质沉淀特征及影响因素分析

为明确CO2在页岩储层纳米孔隙中的流动机理及其对沥青质沉淀的影响,采用自主研发的高温高压过滤容器和复合纳米滤膜,进行纳米滤膜过滤实验,模拟了单(多)层岩石切片作用下的CO2驱替过程,开展储层参数和注入参数对CO2驱替效果及沥青质沉淀的影响研究.研究结果表明:CO2驱会引发沥青质沉淀,导致剩余油中的沥青质含量远大于产出油...

Analysis of Asphaltene Deposition Characteristics and Influencing Factors of CO2 Flooding in Shale Reservoirs

In order to clarify the mechanism of CO₂ flowing in the nano-pores of shale reservoirs and its influence on asphaltene deposition, a nano-filtration experiment was conducted with self-developed high-temperature and high-pressure filtration vessel and composite nano-filtration membrane to simulate the CO₂ flooding process under the action of single (multi)-layer rock slices, and to study the influence of reservoir parameters and injection parameters on CO₂ flooding effect and asphaltene deposition. The results showed that CO₂ flooding caused asphaltene deposition, resulting in the asphaltene content in the remaining much higher than that in the produced oil; the asphaltene content in the produced oil increased with the increase of CO₂ injection pressure and filter membrane pore size, but decreased with the increase of temperature, shut-in duration, membrane thickness and heterogeneity; the influence degree of reservoir parameters and injection parameters on asphaltene deposition was as follows: membrane thickness (40.63%), injection pressure (20.74%), heterogeneity (16.84%), temperature (10.86%), membrane pore size (7.37%), and shut-in duration (3.56%). The study results provide reference and basis for enhancing the recovery efficiency of shale oil reservoirs by CO₂ flooding.