Simulation of Competition Between Transverse Notches Versus Axial Fractures in Open Hole Completion Hydraulic Fracturing

Multi-stage hydraulic fracturing is commonly used in the stimulation of unconventional plays. The long horizontal section of the wellbore is usually drilling along the minimum horizontal stress direction to create several transverse fractures perpendicular to the wellbore axis. The induced fractures are expected to be evenly distributed within each stage to maximize the stimulated reservoir volume. In case of open-hole completion, there could be multiple natural fratures with different orientations and dimensions intersecting the wellbore competing to act as the fracture initiation point. The location and orientation of these fractures may not be the favorable to create a fracture along the most desirable direction to avoid fracture tortusity and screen out. In this study, we use analytical models and latice-based numerical simulations to investigate the most important parameters that control the initiation and near-wellbore propagation of natural fractures. In field applications, we propose to create a small crack around the wellbore (notch) with sufficient length and in a specific direction to dominate existing natural fractures and be the initiation point at a desired location. The results showed that stress anisotropy is the main factor controlling the fracture initiation and the length of the notch required to dominate transverse fracture around the wellbore.