This technology utilizes the existing wellbore structure by first using a small drill bit to open a 22mm window on the casing of the oil reservoir, and then connecting a 12.5mm hose with a nozzle using a continuous oil pipe. With the hydraulic fracturing effect of high-pressure jet, multiple (diameter 25-75mm, length of about 100m) small boreholes are drilled in different directions of the oil reservoir.