Improved Enhanced Oil Recovery – Role of Sonication: An Overview

Crude oil is one of the prominent resources to fulfill the need of day-to-day life. With few reservoirs, the proper utilization and maximization of oil recovery from existing oil wells are one of the foremost objectives in today’s scenario. Conventionally, the inbuilt pressure and artificial pumping followed by water flooding could result in 30-50% of oil recovery. Thus, to produce the remaining residual crude oil, various enhanced oil recovery methods are adopted, including gas flooding, fire flooding, chemical EOR, etc. Still, oil recovery in large quantities persists to be a challenging task for engineers throughout the world. The major limitation for improving the oil recovery is the water enrichment of the reservoirs, which governs the oil displacement efficiency from the reservoir to the production platform. The application of sound waves in reservoir engineering is an established technology. In seismic surveys, sound waves of various frequencies have been used to predict oil and gas reserves. The advancement of the application of ultrasound irradiation on multiple sectors, including the enhancement of oil recovery from wells, has also been analyzed and tested. The idea behind applying cavitation technology is that the passage of ultrasound waves releases the energy in terms of transient cavitation and allows the formation of the fine emulsion of two immiscible phases. The emulsion enables the improvement of oil movability toward the production well without changing the porosity and permeability of rocks. Thus, the cavitation technique can be applied to estimate oil-water saturation in reservoirs and can further improve the oil recovery factor. This chapter emphasizes the fundamentals of enhanced oil recovery schemes, their mechanisms, and the application of ultrasound irradiation toward improved oil recovery. 

Keywords: Cavitation, Crude oil production, Enhanced oil recovery, Emulsion, Permeability, Surface tension.