Title
Experimental and numerical investigation of sandstone deformation under cycling loading relevant for underground energy storage
Author
Naderloo, M. (TU Delft Applied Geophysics and Petrophysics)
Ramesh Kumar, K. (TU Delft Reservoir Engineering)
Hernandez, Edgar (Deltares; Student TU Delft)
Hajibeygi, H. (TU Delft Reservoir Engineering)
Barnhoorn, A. (TU Delft Applied Geophysics and Petrophysics)
Date
2023
Abstract
Considering the storage capacity and already existing infrastructures, underground porous reservoirs are highly suitable to store green energy, for example, in the form of green gases such as hydrogen and compressed air. Depending on the energy demand and supply, the energy-rich fluids are injected and produced, which induces cyclic change of state-of-the-stress in the reservoir and its surrounding. Detailed analyses of the geo-mechanical deformations under variable storage conditions i.e., storage frequency and fluid fluctuating pressures, are crucially important for safe and efficient operations. The present work presents an integrated analysis, based on experimental and constitutive modeling aspects, to investigate sandstones’ geomechanical response to cyclic loading relevant to underground energy storage (UES). To this end, sandstone rock samples were subjected to cyclic loading above and below the onset of dilatant cracking under different frequencies and loading amplitudes. Axial strains and Acoustic Emissions (AE) were measured in both regimes to quantify the total deformation (strain) of the rock and its AE characteristics. It is found that the inelastic strain and number of AE events is the highest in the first cycle and reduce subsequently cycle after cycle. Moreover, cyclic inelastic deformations are affected by the mean stress, amplitude, and frequency of the stress waveform. On the one hand, the higher the mean stress and the amplitude, the higher the total inelastic strains. On the other hand, the lower the frequency, the higher the total inelastic strain. From the modeling perspectives, five types of deformation mechanisms were identified based on the governing physics: elastic, viscoelastic, compaction-based cyclic inelastic, inelastic brittle creep, and dilatation-based inelastic deformation. To model elastic, viscoelastic, and brittle creep, the Nishihara model was used. A cyclic modified cam clay model (MCC) and hardening–softening model were applied to capture plastic deformation. The results show a very good fit of the constitutive model with the experimental results, which could help in studying the response of reservoirs to injection and production.
Subject
Acoustic emissions
Geomechanics
Nonlinear material deformation
Sandstone
Subsurface energy storage
To reference this document use:
http://resolver.tudelft.nl/uuid:60c48965-8070-4abc-b983-5aa4a075c5c4
DOI
https://doi.org/10.1016/j.est.2023.107198
ISSN
2352-152X
Source
Journal of Energy Storage, 64
Part of collection
Institutional Repository
Document type
journal article
Rights
© 2023 M. Naderloo, K. Ramesh Kumar, Edgar Hernandez, H. Hajibeygi, A. Barnhoorn