Study on Repeating Fracturing while Causing No Damage to Original Fractures

When a lost circulation material is used to temporarily plugging the a fracture, new fractures will be forced to propagate in non-fractured zones. This is the so-called "non-damaging to original fractures while fracturing" technology. In the application of this technology, the liquid conductance of the original fractures is not affected while new fractures are being generated. In laboratory studies, a temporarily plugging fluid containing chorionic vesicles increased the flow resistance of artificial core fractures to 25 MPa. When treated with this temporarily plugging fluid, artificial cores (permeabilities 17.5×10-3 μm2 and 164.9×10-3 μm2, respectively) had permeability recovery (to crude oil) of 90.9% in 0.7 hour and 84.7% in 0.6 hour, respectively. When using chorionic vesicle in the operation of the Well LH1, pump pressure was held up at 22.0 MPa for 10 minutes. The daily production rates of liquid and oil 60 days after re-fracturing were increased by 48.0% and 119.2%, respectively, compared with those 30 days before re-fracturing, and the average water cut was reduced by 7.5%. These facts showed the good performance of chorionic vesicle in temporarily plugging fluid in fracturing operation.