Influence of Low-Frequency Vibration Acceleration on the Permeability of Low Permeable Porous Media During Water Flooding

Abstract

Seismic production technology utilized physical wave field to stimulate the reservoir. Though this technology was applied once in the oil fields, the mechanisms were not analyzed comprehensively. Influence of low-frequency vibration acceleration instead of vibration frequency on rock properties of low permeable rock during water flooding was studied thereby. The variations of absolute or relative permeability were talked in detail. With introduction of four relative permeability models, coefficients of the models were matched and the change of pore size of rock under low-frequency vibration was discussed indirectly. It was found that, besides the vibration frequency, the vibration acceleration had also affected the properties of low permeable rock during water flooding. The absolute permeability, which decreased gradually due to stress sensitivity, had been retrieved partly by vibration. When the vibration acceleration was chosen properly, the relative permeability of water phase could be decreased and the relative permeability of oil phase could be enhanced. Because of the improved hydrophilicity of rock by vibration, violent vibration acceleration might enhance the oil recovery in low permeable formation. Through matching four relative permeability models, a mechanism as enlarging the pore size distribution by vibration was verified further. It helped to substitute the capillary force test, which required a static measurement background and provided only experimental data of samples before or after vibration.