A Play-Agnostic Thermo-Poro-Hydro-Mechanical Approximation for Hydraulic Fracture Initiation: Insights on Stress Distortions Between the Wellbore and a Perforation Tunnel

Abstract

ABSTRACT: Predicting near-wellbore hydraulic fracture (HF) orientation is crucial for designing stimulation treatments. This work proposes a physics-based approach to determine the orientation of HF initiation considering formation breakdown pressure (FBP) and key geomechanical parameters. A novel closed-form pseudo three-dimensional (3D) approximation captures thermal, poroelastic, hydraulic, and mechanical effects (TPHM), visualizing the stress distortion at the intersection between the wellbore and a perforation tunnel. While specific formations like the Bakken Shale may present unique challenges, the proposed approach transcends such limitations. The play-agnostic TPHM model allows the identification of favorable conditions for transverse HFs across diverse geological settings and wellbore pressure regimes. This empowers engineers to manipulate controllable parameters, such as wellbore pressure and perforation design, to optimize stimulation treatments in various formations, ultimately maximizing well productivity. By promoting favorable HF initiation and early propagation, this approach has the potential to reduce completion issues, enhance well performance, and contribute to a more efficient and sustainable approach to the development of unconventional reservoirs. 1. INTRODUCTION A number of analytical attempts were made to describe HF initiation from perforated wells. Common to all are two-dimensional (2D) analytical expressions of elasticity relationships, solving the stresses on the wellbore walls. While these models are elegant closed-form expressions of the HF initiation and are particularly useful in practical HF design, they do not consider the presence of perforation tunnels intersecting the wellbore. Economides et al. (1989) described the stimulation of horizontal wells and the criteria for the decision between longitudinal (axial to the wellbore) and transverse (orthogonal to the wellbore) HFs, as displayed on Fig. 1. Multiple transverse-HF initiations from horizontal wells is the desired outcome of modern-day reservoir stimulation operations. This is despite that in a transverse HF, the flow regime from the reservoir into the HF is linear, while the flow inside the HF is radial, resulting in a pressure drop that contributes to the well's skin. Being able to "stack" multiple transverse HFs near each other in shales will outperform a gigantic longitudinal HF, which is the inadvertent outcome of multiple longitudinal-HF initiations from a horizontal well's lateral.