Mechanical principles of hydraulic pressure fluctuation injection based on fracturing technology

A new hydraulic pressure fluctuation injection method based on fracturing technology was proposed to improve the stimulation effect of hydraulic fracturing and solve the high pump pressure during the hydraulic fracturing of coiled tubing annulus. The change laws of borehole pressure system under hydraulic pressure fluctuation injection were illustrated according to the principle of hydraulic fracturing. Moreover, the basic mechanical principles of hydraulic pressure fluctuation injection based on fracturing technology were established according to the theories of fluid mechanics, elasticity and wave mechanics. It indicates that the flowing fluid in the borehole undergoes energy transfer and unstable pressure fluctuation occurs near the bottom hole under hydraulic pressure fluctuation injection. And this kind of unstable pressure fluctuation generated by unstable injection flow rate is propagated in the form of pressure wave in reservoir fractures. When the hydraulic pressure vibration wave propagates along the direction of fracture length, it doesn't propagate at the constant pressure amplitude and the propagation presents the law of pressure amplitude depletion. The length and width of hydraulic fractures increase with the running rotation speed of fracturing pump. In conclusion, hydraulic pressure fluctuation injection based on fracturing technology can improve the stimulation effect of hydraulic fracturing and increase the production rate of oil and gas wells. It is recommended to apply this technology to the field hydraulic fracturing. The results provide the new method and theoretical basis for improving the stimulation effect of hydraulic fracturing.