METHOD FOR DISPLACEMENT OF RESERVOIR OIL BY WATERFLOODING AT MICROFRACURING PRESSURE OF LOW/ULTRA-LOW PERMEABILITY RESERVOIR

A method for displacement of reservoir oil by waterflooding at a microfracturing pressure of a low/ultra-low permeability reservoir. For the characteristics of the low/ultra-low permeability reservoir, intelligent software is used to dynamically monitor on line and in real 10 time and automatically control a waterflooding pressure, a waterflooding amount and a temperature, so that a large number of microfractures are formed in a stratum. Water is injected at a microfracturing pressure, and the stratum is filled with the microfractures. If some microfractures are connected in series with natural fractures to form high permeability passages, a plugging agent is immediately injected for plugging. Finally, the stratum is full of the 15 microfractures, and flood water can be easily injected and will not break through along the high permeability passages. Therefore, the sweep efficiency of the flood water is improved to the maximum extent, and the recovery efficiency is improved. FIG. 1 20