THE PERFORATION PARAMETER OPTIMIZATION FOR MULTI FRACTURE INITIATION IN HYDRAULIC FRACTURING

A model of damage mechanics of fluid and solid near the wellbore is established, for the multi-fracture initiation near wellbore under complicated geological conditions, and the distribution of stress and damage of perforated wall is obtained by numerical analysis. Calculation shows that the smaller the crustal stress value is, the smaller the well perforation azimuth angle is, the lower the crack pressure will be. The crack stress increases with the increase of the perforation azimuth angle. When the near wellbore has inflexion cracks and an angle of 45° micro crack, the crack pressure increases. Based on this conclusion, the perforation azimuth angle is less than 30° for normal fault and smooth fault, when the spiral perforation angle is 30° or 45° and the thrust fault is 45°, multi-fracture initiation will be implemented effectively.