Experimental Study of Perforation Parameters Impact on Oil Shale Hydraulic Fracturing

At present, Most of the oil shale in-situ heating technology need to hydraulic fracturing in oil shale formation. Nearly all hydraulic fracturing is carried out after the casing perforation. Perforation parameters play an important role among hydraulic fracturing construction parameters, which even affect effect of oil shale in-situ heating. The hydraulic fracturing process of indoor physical simulation experiment is carried out with the same formation conditions and different perforation parameters. The effect of perforation diameter, perforation orientation (the angle between the direction of perforation and the direction of maximum horizontal stress) and perforation density to fracturing pressure and fracture propagation are researched. The experimental results show that fracturing pressure reduces with perforation diameter increasing, but the effect is not obvious. Fracturing pressure increases obviously with perforation orientation increasing, and fracture becomes more complex. Fracturing pressure decreases obviously with perforation density increasing, which has a very small impact on fracture propagation.