Abstract: Spontaneous imbibition experiments of tight sandstone were carried out through NMR technology, imbibition characteristics of waterwet tight core with neutral core were compared, and the influences caused by sodium dodecyl sulfate with different concentrations towards neutralwet tight sandstone imbibition were analyzed. The results show that recovery efficiency of waterwet tight core is above 60%, neutralwet core is above 35%, and the imbibition is an effective way for the development of tight oil reservoir. It is also found that SDS can disperse oil in core, promote the oil flow fast in core, increase the speed of tight sandstone imbibition, which is effective for both neutralwet tight sandstone and waterwet tight sandstone. Sodium dodecyl sulfate can also increase oil phase recovery in middle and small pores, especially in small pores of neutralwet core, and improve the spontaneous imbibition experiments recovery. Under the experimental conditions, 0.05% sodium dodecyl sulfate is the most effective for waterwet core.

Key words: Tight sandstone,    , Spontaneous imbibition,    , Sodium dodecyl sulfate,    ,  Nuclear magnetic resonance

摘要： 通过核磁共振测试的方法开展了致密砂岩的自发渗吸实验, 对此研究了致密水湿岩心和中性岩心的 自发渗吸特征, 分析了不同质量分数的十二烷基硫酸钠对致密中性岩心渗吸的影响。渗吸实验结果表明, 致密水湿 砂岩的采收率在6 0%以上, 致密中性砂岩采收率在3 5%以上, 渗吸采油的方法可以作为致密油开发的一种有效方 式。研究也发现, 无论是中性润湿的致密砂岩, 还是致密水湿砂岩, 十二烷基硫酸钠都可以使岩心内油滴分散变小, 改善油珠的流动情况, 从而提高致密砂岩的渗吸速度。十二烷基硫酸钠也能够显著提高中小孔隙, 尤其是中性岩心 中的小孔隙内油相的动用程度, 从而提高渗吸采收率。在实验条件下, 质量分数为0. 0 5%的十二烷基硫酸钠在提高 致密中性岩心渗吸采收率方面效果最佳。

关键词: 致密砂岩,  , 自发渗吸,  , 十二烷基硫酸钠,  , 核磁共振