Study On Propagation Characteristics Of Pulsing In Vertical Fractures During Low-frequency Hydraulic Pulsing Fracturing

Hydraulic fracturing technology is the main stimulation measure for low-permeability oil and gas reservoirs.The main problems at present are fracture initiation,fracture extension control and how to effectively improve fracture conductivity.In this paper,based on the underground low-frequency hydraulic pulsing fracturing technology,for the propagation of pulsing pressure in vertical fractures,Fluent software is used,and the turbulence model is adopted to simulate the actual hydraulic fracturing conditions.The influence of sand and other sensitive construction parameters on the pressure attenuation of pulsing pressure in vertical cracks.The effects of key parameters such as pulsing frequency,fracture size,and sand content in fracturing fluid on transient pressure model were mainly studied,and the following research insights were obtained:(1)The calculation of pressure retention amplitude shows that within the range of 5-30 Hz pulsing frequency,as the half-slot length increases,the pressure retention amplitude decreases;when the pulsing frequency is 25 Hz,the pressure retention amplitude is larger;when the pulsing frequency is 30 Hz,The pressure remains small.(2)The calculation of the maximum fluctuation pressure retention amplitude shows that within the range of 5-30 Hz pulsing frequency,the maximum fluctuation pressure retention amplitude increases in the half-seam length of 60m-70m;when the pulsing frequency is 20 Hz,the maximum fluctuation pressure retention amplitude The maximum pulsing pressure fluctuation range can be maintained above 0.5kPa when the half-slit length is 30m-60 m and the fracture half-length is 80 m.The larger the fracture height,the larger the maximum fluctuation pressure retention range.(3)When the pulsing frequency is 20 Hz,the sand content has little effect on the maximum fluctuation pressure retention range and pressure retention range;when the sand content is 0.3,within the 15-25 Hz pulsing frequency range,as the half-slot length increases,The pressure retention range decreases,and the maximum fluctuation pressure retention range increases with a half-slit length of 60 to 70 meters.When the pulsing frequency is 20 Hz,the maximum fluctuation pressure retention range is larger with a half-slit length of 20 to 50 meters.The conclusions of related downhole low frequency hydraulic pulsing research can be used for reference in the field application.