The oil and gas industry is plagued by inevitable formation damaged in the wellbore proximity during entire life of the well. Therefore, it is indispensable to ameliorate the damaged permeability by either using conventional applied techniques or ultrasonic-assisted stimulation method. The latter is characterized by efficient, simple and convenient, and environmentally secure method. Due to these distinguished characteristics, the demand of this physical Enhanced Oil Recovery (EOR) technique increased in petroleum industry. In this study, ultrasonic waves and hydrochloric acid (HCl) were used separately as well as in combination to recover the lost productivity caused by calcium carbonate (CaCO₃) inorganic plugs in low permeability sandstone core samples. Results showed that permeability recovery increased with irradiation time up to 100 min; however, it decreased with further irradiation. This deviation could be due to particles bridge formation at later stage. In addition, optimum frequency and power of ultrasonic waves (20 kHz and 1000 W) significantly recovered the damaged permeability. Although maximum frequency (25 kHz) could not achieve maximum permeability, but higher power was quite effective. The damaged permeability recoveries of HCl and ultrasonic waves were 44.5% and 37.6% respectively, but the permeability recovery was escalated to 61.5% when HCl and ultrasonic techniques were applied together. Inorganic plugs using ultrasonic waves could chiefly be caused by cavitation, acoustic streaming, and heat generation in three different ways, such as cavitation, boundary friction and transformation upon hitting the medium.

中文翻译：

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酸化和超声波的比较，以及它们在缓解无机栓塞方面的协同作用

石油和天然气行业在井的整个生命周期中都不可避免地受到地层损坏的困扰。因此，通过使用常规应用技术或超声辅助刺激方法来改善受损的渗透性是必不可少的。后者的特点是高效，简单，方便且对环境安全的方法。由于这些杰出的特性，石油工业对这种物理增强油采收率（EOR）技术的需求增加了。在这项研究中，分别使用超声波和盐酸（HCl）并结合使用，以恢复由碳酸钙（CaCO ₃）低渗透率砂岩岩心样品中的无机塞。结果表明，渗透率的恢复随着辐照时间的延长而增加，持续时间可达100 min。但是，随着进一步的照射，它减少了。该偏差可能是由于在后期阶段形成了颗粒桥。此外，超声波的最佳频率和功率（20 kHz和1000 W）可以显着恢复受损的磁导率。尽管最大频率（25 kHz）无法达到最大磁导率，但更高的功率却非常有效。HCl和超声波的破损渗透率回收率分别为44.5％和37.6％，但同时使用HCl和超声波技术，渗透率恢复率提高至61.5％。使用超声波的无机塞子可能主要是由空化，声流，