A Hybrid Data-Driven/Physics-Based Approach for Near-Wellbore Hydraulic Fracture Modeling

Abstract

Abstract Variables affecting the near-wellbore region of a fractured well have a big impact on its post-stimulation well performance. Optimal hydraulic fracture (HF) initiation and early-phase propagation results in minimal near-wellbore tortuosity, decreasing the likelihood of screenouts and maximizing the resultant well productivity. While most predictive models for the HF geometry produced in a stimulation treatment consider the far-field region, the near-wellbore vicinity should be an integral part of a properly-engineered reservoir exploitation strategy, impacting the treatment's design and execution. In this work, a hybrid data-driven/physics-based approach is elaborated for modeling HF initiation and early-phase propagation from perforated horizontal wells. An optimization scheme via oriented perforating is presented using the developed hybrid model, considering the orientation of the induced HF initiation (longitudinal or transverse with respect to a well drilled along the minimum horizontal in-situ principal stress) and the resultant formation breakdown pressure (FBP); the highest the wellbore pressure reached during the treatment. Transverse HF initiation (and early-phase propagation) is ideal for wells drilled in low-permeability "tight" formations, while FBP minimization decreases the overall on-site horsepower requirements for the stimulation treatment. The demonstrated optimization scheme is applied separately to the in-situ stress states of seven prolific shale plays from the U.S. and Argentina, suggesting oriented-perforating strategies targeting the promotion of transverse HF initiation in two of these (Barnett and Marcellus), while targeting FBP minimization in the remaining five (Bakken, Fayetteville, Haynesville, Niobrara, and Vaca Muerta). The effectiveness of such oriented-perforating strategies can potentially be compromised by fracturing fluid leakage around the borehole's circumference, which is shown to hinder transverse HF initiation. The hybrid model is also used to estimate fracture initiation pressure (FIP) values for the seven shale plays studied, indicating significant discrepancies with analytical expressions used to approximate these FIPs in modern-day HF computational simulations. Finally, the framework is set for expanding this modeling approach over a range of in-situ stress states, incorporating data-driven (numerically-derived) aggregate correction factors to compensate for inaccuracies in the analytical approximations, which comprise the physics-based core of the proposed hybrid model. The impact of perforation geometry was not addressed in this study.