arXiv subjects

Gaspare Da Fies

Publications and source records attributed to Gaspare Da Fies.

4 recordsLinked to original sources

arXiv2025

Peculiarities of hydraulic fracture propagation in media with heterogeneous toughness: the energy balance, elastic battery and fluid backflow

This paper investigates hydraulic fracture in a media with periodic heterogeneous toughness. Results for the plane-strain (KGD) model are analysed. The energy distribution as the fracture propagates is examined, along with the evolution of the crack geometry. It is shown that the solid layer acts as an elastic battery, discharging to promote rapid propagation through weaker material layers. The limiting case of an infinite-length crack is discussed. The velocity of the fluid throughout the crack length is also considered. For fractures in high-toughness material it is shown that fluid backflow can occur, with its profile dependent on the toughness distribution. The implications of these findings are discussed.

physics.geo-ph↗

arXiv2022

Averaging-based approach to toughness homogenisation for radial hydraulic fracture

The homogenisation of the fracture toughness is considered in the context of a propagating hydraulic fracture. The radial (penny-shape) model is utilized, in order to incorporate the impact of the viscosity-toughness regime transition over time. A homogenisation strategy based upon temporal-averaging is investigated. This approach incorporates the instantaneous fracture velocity, meaning that it should remain effective in the case of step-wise crack advancement. The effectiveness of the approach is demonstrated for periodic toughness distributions, including those which are unbalanced, utilizing a highly accurate solver.

physics.geo-ph↗

arXiv2022

Impact of the tangential traction for radial hydraulic fracture

The radial (penny-shaped) model of hydraulic fracture is considered. The tangential traction on the fracture walls is incorporated, including an updated evaluation of the energy release rate (fracture criterion), system asymptotics and the need to account for stagnant zone formation near the injection point. The impact of incorporating the shear stress on the construction of solvers, and the effectiveness of approximating system parameters using the first term of the crack tip asymptotics, is discussed. A full quantitative investigation of the impact of tangential traction on solution is undertaken, utilizing an extremely effective (in-house build) adaptive time-space solver.

physics.geo-ph↗

arXiv2022

A temporal-averaging based approach to toughness homogenisation in heterogeneous material

A new approach to defining the effective fracture toughness for heterogeneous materials is proposed. This temporal averaging approach is process-dependent, incorporating the crack velocity and material toughness. The effectiveness of the new technique is investigated in the context of hydraulic fracture through heterogeneous rock with a periodic material toughness. The plane strain model is considered without fluid leak-off, to more easily investigate different regimes (toughness/viscosity). Numerical simulations are used to examine the effectiveness of the new homogenisation strategy, with comparison against the recently-proposed maximum toughness strategy. Simulations are conducted using an extremely effective (in house-built) time-space adaptive solver. The regimes in which each strategy is effective are determined.

physics.geo-ph↗