Influence of pore pressure to the development of a hydraulic fracture in poroelastic medium

TL;DR

This study introduces a novel numerical model to analyze how pore pressure influences hydraulic fracture development in poroelastic media, emphasizing the importance of stress analysis and fluid exchange for accurate modeling.

Contribution

The paper presents a new mesh-independent numerical model for hydraulic fracture propagation in poroelastic media and analyzes the impact of pore pressure on fracture length and stress distribution.

Findings

Fracture length decreases with higher Biot's number.

The model converges numerically and matches known solutions.

Stress redistribution near the fracture is significantly affected by pore pressure.

Abstract

In this paper we demonstrate the influence of the pore pressure to the development of a hydraulically-driven fracture in a poroelastic medium. We present a novel numerical model for propagation of a planar hydraulic fracture and prove its correctness by demonstration of the numerical convergence and by comparison with known solutions. The advantage of the algorithm is that it does not require the distinguishing of the fracture's tips and reconstruction of the numerical mesh according to the fracture propagation. Next, we perform a thorough analysis of the interplay of fluid filtration and redistribution of stresses near the fracture. We demonstrate that the fracture length decreases with the increase of the Biot's number (the parameter that determines the contribution of the pore pressure to the stress) and explain this effect by analysing the near-fracture pore pressure, rock deformation and stresses. We conclude, that the correct account for the fluid exchange between the fracture and the rock should be based not only on physical parameters of the rock and fluid, but also on the analysis of stresses near the fracture.