## 1 Introduction  
The precipitation of paraffins during oil production is a widespread phenomenon that petroleum engineers struggle with. In addition to being precipitated inside the surface pipelines [1] and well tubing [2, 3], paraffins and asphaltenes are also precipitated in the reservoir as a result of both a decrease in reservoir temperature due to cold water flooding [4] and a reservoir pressure drop [5]. Among the entire reservoir, the highest intensity of paraffin precipitation due to changes in reservoir pressure is observed near production wells, where there is a significant drop in reservoir pressure [6] caused by well performance. Paraffin flocculation blocks the pore channels of the rock, which is commonly called \"formation damage\" [7]. As a result, the rock permeability of the bottomhole formation zone deteriorates and the flowrate of the production well decreases, which can adversely affect production from the entire oil field. In order to unblock the pore space, production engineers use bottom-hole formation treatments (for example, steam cycle, acid, and others). However, due to the constant influx of fluid from the reservoir and new precipitations of paraffins and asphaltenes, such treatments have to be repeated, including shutting down the well and production. An alternative solution is nonlinear load treatment [8; 9], which can be performed without shutting down the well [10]. Nonlinear load treatments use elastic wave generators of various types that produce vibrations propagating towards the productive formation. A significant number of theoretical and experimental works are devoted to studying the effect of nonlinear loading on the filtration of single-phase and two-phase fluids in a porous medium, the mobilization of capillary-trapped oil, changes in the rheological characteristics of filtering fluids, and other phenomena (see reviews [11; 12], as well as the development of downhole tools (see review of [13; 14]). Treatment of low-permeability sandstone with ultrasonic vibrations increases the spontaneous capillary imbibition of water by the rock sample [15]. Treatment of coal samples in an experimental setup with an ultrasonic emitter demonstrates a significant improvement in their permeability [16]. To restore the permeability of rocks near the wellbore, many authors explore the ultrasonic method of removing the pore space of the rock from precipitation of inorganic substances (salts), drilling fluid, and well-killing fluid, as well as polymers. For example, ref. [17] has shown in the experimental installation for core flooding that ultrasonic vibrations remove calcium carbonate plugs at frequencies of 18-50 kHz. In the work of [18] on an experimental set-up, the authors restored the permeability of artificial rock samples clogged with inorganic substances (CaCO\({}_{3}\)), paraffin deposits, drilling fluid, fine-grained substances, in situ fines, and polymers using ultrasonic vibrations. Deposits of inorganic substances such as KCl and NaCl are also removed from samples under the action of ultrasonic vibrations with a frequency of 22 kHz [19; 20]. Ultrasonic impact destroys and removes the drilling fluid and completion fluid that clogged the pore space [21]. The value of the restored permeability is significantly affected by such parameters as frequency, specific power, duration of ultrasonic treatment, and the initial permeability of the core. Treatment at 20 kHz, compared to 18 kHz and 25 kHz, best restores the permeability of quartz and epoxy rock samples degraded by brine injection [22]. Despite the results achieved in the study of pore space removal from inorganic substances, there are very few experimental data among laboratory studies that could demonstrate the effect of nonlinear loads on the intensity of paraffin and asphaltene precipitation in rock and on the permeability of rocks during crude oil filtration. Existing studies indicate that high-frequency nonlinear loading has a positive effect on the permeability of the rock in the presence of paraffins.