Research and Application of New Refracturing Technology in Low Permeability Oilfield

Production from the Chang X reservoir of the Ordos Basin has been declining due to the petrophysical properties of the producing formation, induced fractures,and other factors, and the displacement effect with water. As a result, there is large amount of remaining oil distributed at both sides of induced fractures, and it is difficult to tap.To optimally recover the remaining oil, improve output and recovery, according to the concept of "control of fracture length + multi-fracture fracturing + tap much remaining oil", this paper presents a new multi-refracture stimulating technology (NMST) through numerical simulation, which can increase fracture width, create new fractures in different directions, and take such measures as temporary plugging inside fracture, raising flow rate properly, using low viscous fluids, etc. Field testing shows that the single-well daily average output is 1.9 times that of conventional technology, fracture belt and fractured formation volume increased by 21 m and 148% respectively. The NMST provides a new way to improve recovery of oil in the low-permeability reservoirs in the Ordos Basin.