A Thermal–Hydraulic–Mechanical–Chemical Coupling Model for Acid Fracture Propagation Based on a Phase-Field Method

verfasst von
Yifan Dai, Bing Hou, Sanghyun Lee, Thomas Wick
Abstract

Acid fracturing is a technique to enhance productivity in carbonate formations. In this work, a thermal–hydraulic–mechanical–chemical (THMC) coupling model for acid fracture propagation is proposed based on a phase-field approach. The phase-field variable is utilized as an indicator function to distinguish the fracture and the reservoir, and to track the propagation of the fracture. The resulting system is a nonstationary, nonlinear, variational inequality system in which five different physical modules for the displacement, the phase-field, the pressure, the temperature, and the acid concentration are coupled. This multi-physical system includes numerical challenges in terms of nonlinearities, solution coupling algorithms, and computational cost. To this end, high fidelity physics-based discretizations, parallel solvers, and mesh adaptivity techniques are required. The model solves the phase-field and the displacement variables by a quasi-monolithic scheme and the other variables by a partitioned schemes, where the resulting overall algorithm is of iterative coupling type. In order to maintain the computational cost low, the adaptive mesh refinement technique in terms of a predictor-corrector method is employed. The error indicators are obtained from both the phase-field and concentration approximations. The proposed model and the computational robustness were investigated by studying fourteen cases as well as some mesh refinement studies. It is observed that the acid and thermal effect increase the fracture volume and fracture width. Moreover, the natural fractures and holes affect the acid fracture propagation direction.

Organisationseinheit(en)
Institut für Angewandte Mathematik
Externe Organisation(en)
China Univeristy of Petroleum - Beijing
Florida State University
Typ
Artikel
Journal
Rock Mechanics and Rock Engineering
ISSN
0723-2632
Publikationsdatum
01.03.2024
Publikationsstatus
Elektronisch veröffentlicht (E-Pub)
Peer-reviewed
Ja
ASJC Scopus Sachgebiete
Tief- und Ingenieurbau, Geotechnik und Ingenieurgeologie, Geologie
Elektronische Version(en)
https://doi.org/10.1007/s00603-024-03769-x (Zugang: Geschlossen)