Our SFB 1313 doctoral researcher Alixa Sonntag (research project B02) successfully defended her doctoral thesis "Partially Saturated Porous Solids under Dynamic Hydraulic Fracturing" on 24 November 2023. Congratulations!
Alixa Sonntag is a doctoral researcher at the Institute of Applied Mechanics (CE) of the University of Stuttgart and is a member within the framework of SFB 1313 and the Integrated Research Training Group IRTG-IMPM.
Abstract
Hydraulic fracturing is a technique where fracking fluids are pressed into the ground to initiate and open fractures, increasing the rock's permeability. Although this technique is widely used in practice, the fracturing process is controversially discussed and scientifically still not well established. Based on methodical developments, this doctoral thesis enlarges the understanding of the coupled processes occurring during fluid-driven fracturing in partially saturated porous media, where the pore space of the solid skeleton contains both an incompressible liquid and a compressible pore gas.
The Theory of Porous Media (TPM) allows a rigorous and consistent formulation of the coupled behaviour of the abovementioned three phases. In addition, a phase-field approach is embedded in the elaborated TPM model to consider fracturing processes in the porous material. Here, special attention is given to describing the fluid flow and pressure behaviour in the pore space during fracturing.
The model is applied to various numerical examples within the finite-element framework. Besides a detailed analysis of the coupled process during fracturing and accompanying fluid interaction, also heterogeneities in the porous structure and stresses are assessed.