Energy dissipation mechanisms in fluid driven fracturing of porous media

Abstract: We present a novel approach for calculating the energy dissipated during fluid driven fracturing in saturated porous media. Analytical functions describing both of the solid and fluid energy dissipation modes are derived based on a thermodynamic formulation for Non Local Damage and Transport (NLDT) in porous media. The thermodynamically consistent NLDT model derivation leads to a system of non-linear equations which are solved numerically in a mixed finite element framework. The proposed model is used to simulate hydraulic fracturing in a benchmark example and the aspects of energy dissipation are investigated. In this formulation, hydraulic fracture is presented as a disturbance of two continuum fields: (1) damage which describes the degraded stiffness of the solid material, and (2) non-liner permeability which evolves in the fracture zone to describe the elevated fluid flow velocity. A parametric study is performed to investigate the various mechanisms in different cases of loading and material properties. The model provides physics-based grounds for hydraulic fracturing optimization based on improved understanding of energy dissipation mechanisms Article Highlights: A detailed study of hydraulic fracturing energy budget is presentedThe underlying model is a continuum Non Local Damage Transport (NLDT) modelEnergy supplied through fluid injection can be either stored as elastic energy, or dissipated through fluid viscous flow and solid damage mechanismsEnergy storage and dissipation functions are analytically derived and computed quantitatively based on a mixed FEM modelQuantitative calculations of energy storage and dissipation are in agreement with available experimental and field dataThe study of energy budget can lead to advances in the hydraulic fracturing optimization.