为研究CO2驱沥青质沉积对不同渗透率储集层的微观伤害机理,选取低渗、中渗和高渗岩心进行CO2驱室内实验,并应用核磁共振技术定量分析驱替后岩心孔喉空间的堵塞程度.实验结果表明,在混相驱阶段,沥青质沉积率明显高于非混相驱阶段,且在不同渗透率岩心中的沉积率基本相同;渗透率伤害率与沥青质沉积率呈正相关,且岩心渗透率越大,渗透率伤害率越小;在混相驱阶段,低渗岩心孔喉堵塞严重,较小孔喉(0.01～1 ms)的堵塞率达到38.19％,高渗岩心的较小孔喉(0.1～5 ms)堵塞率仅有9.59％,显著小于低渗岩心.%In order to study microscopic damage mechanism of asphaltene deposition on reservoirs with different permeabilities during CO2flooding,cores with high,medium and low permeabilities are selected for indoor CO2 flooding experiments and plugging degree of pore throat in cores are analyzed quantitatively by using NMR technology.The experimental results show that the deposition rate of asphaltene during miscible phase stage is obviously higher than that during immiscible phase stage,and the deposition rates are basically same in the cores with different permeabilities;permeability damage rate is positively correlated with the asphaltene deposition rate and the larger the core permeability,the smaller the permeability damage rate;the pore throats in low-permeability cores are blocked seriously with the plugging rate of relatively small pore throats (0.01 ～ 1 ms) reaching 38.19％,the plugging rate of relatively small pore throats in high-permeability cores is only 9.59％,which is significantly lower than the previous one.
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