松辽盆地北部致密砂岩高温高压吞吐渗吸实验

摘要

In order to further clarify the displacement mechanism of huff-puff imbibition in tight sandstone reservoir and optimize huff-puff imbibition media,the laboratory physical simulation method and device are established to accurately model the dynamic production process of high temperature-pressure huff-puff imbibition in tight sand-stone reservoir.The natural core samples of tight sandstone reservoir in northern Songliao Basin are taken to conduct laboratory experiments and identify the effects of poroperm properties,oil-water viscosity ratio,wettability,imbibi-tion volume-surface ratio,imbibition media,producing pressure drawdown and other factors on the huff-puff imbi-bition performance in tight sandstone reservoir. Research indicates that The huff-puff imbibition recovery degree in the tight sandstone reservoir of northern Songliao Basin increases with the increase of reservoir poroperm properties and decreases with the increase of oil-water viscosity ratio and imbibition volume-surface ratio. The imbibition dis-placement performance of water-wet sample is better than that of oil-wet sample under the condition of equal po-roperm properties. Fracture can enhance the imbibition displacement performance. There is no significant effect on imbibition performance by increasing producing pressure drawdown within the range of imbibition displacement,but it can increase the flowback ratio. The imbibition displacement performances of different water types from high to low are active water,low-salinity water and simulated formation water. The huff-puff imbibition displacement per-formance of guar gum fracturing fluid is relatively poor due to its damage to reservoir and it is suggested to shorten its residence time in formation. This research could provide certain reference and guidance for the efficient imple-mentation of huff-puff imbibition displacement in the tight sandstone reservoir of northern Songliao Basin.%为明确致密砂岩储层的吞吐渗吸采油机理,优选最佳吞吐渗吸介质,建立了可准确模拟致密储层动态高温高压吞吐渗吸采油过程的物理模拟实验方法和装置,并选取松辽盆地北部致密砂岩储层天然岩心,开展了孔渗物性、油水黏度比、润湿性、渗吸体面比、渗吸介质及生产压差等因素对致密储层吞吐渗吸开发效果的影响实验研究.结果表明:松辽盆地北部致密砂岩储层吞吐渗吸采出程度随着孔渗物性的增加而增大,随着油水黏度比和渗吸体面比的增大而减小;相同物性级别的亲水岩心渗吸驱油效果好于亲油岩心;裂缝的存在可增加渗吸开发效果;在渗吸置换作用的范围内,提高生产压差对增加渗吸驱油效果的作用不显著,但可提高返排效率.研究认为,活性水的渗吸驱油效果好于低矿化度清水,低矿化度清水好于模拟地层水,胍胶压裂液滤液对储层有一定的伤害,其吞吐渗吸驱油效果较差,建议缩短压裂液在地层中的滞留时间.研究成果可为松辽盆地北部致密砂岩油藏吞吐渗吸开发技术的高效应用提供借鉴和指导.