Single-screw extruders are the most common equipment used for polymer extrusion. The study of the hydrodynamics of a polymer melts flow in the extruder channel is the basis for modeling and understanding the extrusion process. In general form, the extruder includes a straight section with a screw installed in it. In this study, the three-dimensional mathematical modeling of the polymer solutions flow in the metering zone of a single-screw extruder is performed. The influences of the screw geometry (L/D₂ = 1…3) on the flow structure and the pressure drop are analyzed under a speed rotation up to 60 rpm. Aqueous solutions of 0.5% polyacrylamide (0.5% PAA) and 1.5% sodium salt of carboxymethyl cellulose (1.5% CMC) are considered as the working fluid.

Elastic vibrations can increase the effectiveness of oil extraction. The most successful results for oil extraction can be achieved by a combination of the elastic-wave action with other methods of enhanced oil recovery. The authors describe field tests of the use of elastic-wave action on an oil recovery process with in situ combustion. The experiment was performed for over five years in various plots of the Mordovo-Karmalskoye oil field. As a result of this combination, oil production was increased, water cut recoverable products were decreased, and unit costs were decreased. Physical mechanisms are proposed to explain this phenomenon.

The relevance of the work is caused by the need to solve the problems arising in the development of oil fields: reducing the production rate; deterioration of reservoir filtration properties; increasing water cut of produced oil. The impact on the formation of elastic vibrations in a wide frequency range is considered a promising technology to stimulate and increase oil production. However, the large-scale introduction of such methods is constrained by insufficient understanding of the physics of the processes involved. Objective: to identify mechanisms of improving the permeability of porous media and reservoirs under acoustic influence on them based on theoretical and experimental studies, field tests; to identify priorities for future scientific and practical developments in the application of acoustic technologies to intensify oil production. Methods: analysis of the results of laboratory studies and generalization of experience in the application of acoustic and ultrasonic impact methods on productive formations to intensify oil production. Objects: productive formations of oil fields; contaminated bottomhole zone of wells; samples of porous medium from terrigenous and carbonate reservoirs. Results. The paper introduces the review of the results of theoretical, laboratory, and field studies of methods to improve the efficiency of oil production due to the wave action on the environment by elastic oscillations. The authors analyzed the phenomena occurring during this action in the productive formation. It is noted that most studies in this area refer to the ultrasonic exposure and mainly in laboratory conditions. The paper considers the phenomenon leading to increase in porous media permeability under this impact. In particular, the propagation of elastic vibrations contributes to the prevention of deposition of organic and inorganic sediments, restoration and increase of permeability of saturated porous media, removal of plugs and various deposits in carbonate and terrigenous reservoirs. The directions of promising research are formulated; recommendations for improving oil production through acoustic impact are given. The conducted analysis and generalization confirm that the impact of elastic oscillations in a wide range of frequencies activates various chemical and physical processes, affects the filtrationcapacitive properties of productive formations and contributes to oil production intensification.