Mapping natural fracture networks using geomechanical inferences from machine learning approaches

Traditional stochastic algorithms for characterizing fracture networks are purely based on statistical inferences from outcrop images, and therefore the models produced, may not be physically realistic because they may not be consistent with the process of propagation and termination of fractures. These processes are better represented in geomechanical models of the fracturing process. However, full-physics numerical models are computationally inefficient for modeling fractures at a reservoir scale while accounting for material heterogeneities. More importantly, geomechanical simulations yield deterministic results, thus failing to represent the inherent uncertainties due to input properties and paleo stress conditions. In order to facilitate geomechanical characterization, in this research, a number of small-scale, high fidelity, finite discrete element method (FDEM) based forward models are executed and the relationship between prevailing stress conditions and the fracture propagation direction is inferred using Machine Learning (ML) approaches. We develop a ML based fracture network modeling approach that is orders of magnitude faster, efficiently scalable and may extend the capabilities of statistical fracture modeling approaches by accounting for the physical process of fracture propagation and uncertainties associated with geomechanical parameters. The application and effectiveness of this ML based modeling approach is demonstrated using a synthetic case and a case study from Teapot Dome, Wyoming based on the fracture characteristics inferred from the FMI logs near well 67-1-x-10 in the Tensleep Formation reported by Schwartz (2006).