注入速度对砂岩渗吸性的影响

研究了盐水注入速度对亲水砂岩渗吸规律和采收率的影响,对比分析了静态渗吸与动态渗吸结果,研究结果表明,随着盐水注入速度的增加,动态渗吸采收率先快速增加后迅速下降,直至趋于稳定,采收率与注入速度呈单峰变化形态。动态渗吸采收率低于静态渗吸采收率,说明油藏渗吸需要足够时间才能充分发挥毛细管力渗吸作用。故采用渗吸技术时,注入速度应适当低速,生产上可采用间歇注采或者周期注采等措施以提高渗吸采收率。

Effect of Injection Rate on Spontaneous Imbibition of Sandstone

The effect of brine injection rate on spontaneous imbibition behavior and recovery of sandstone is studied, and the ultimate recovery comparison between static imbibition and dynamic imbibition is conducted. The results show that with the increase of brine injection rate, the dynamic imbibition recovery increases and decreases, rapidly, and then tends to be stable, with mono-peak variation in oil recovery and brine injection rate. The fact that dynamic imbibition recovery is lower than static one indicates that spontaneous imbibition of sandstone needs enough time to full exert capillary imbibition in low permeability reservoir. So the injection rate should be low, and measures including intermittent and cyclic injection and production should be adopted in order to increase the spontaneous imbibition recovery.