Affiliation:
1. School of Architecture and Planning, Yunnan University, Kunming 650091, China
2. School of Information Engineering, Kunming University, Kunming 650214, China
Abstract
During the long-term storage of radioactive waste, the continuous generation of gas in the disposal area may influence the integrity of host rock. Thus, the investigation of gas migration and breakthrough in low-permeability rock is indispensable for the stability assessment. In this work, the pore space models of four potential host rocks (Boom clay, COx argillite, Opalinus clay, and Beishan granite) were generated via the binarization of the Gaussian random field. This method provides a randomly formed pore network that does rely on an initial definition of pore shape. The constructed models were analyzed and validated by using the mathematical morphology. A numerical calculation scenario of gas breakthrough on the basis of the Young–Laplace equation was proposed and applied. Results show that the gas breakthrough pressures are 2.62–4.11 MPa in Boom clay and 3.72–4.27 MPa in COx argillite. It enhances the idea that the capillary-induced gas breakthrough is possible at pressures lower than the fracture threshold. For Opalinus clay and Beishan granite, no connected pathway exists, and the breakthrough is more likely to occur through pathway dilation or fractures. The presented method has the advantage of experimental reproducibility and brings a new idea for the investigation of fluid migration in low-permeability rocks.
Funder
Applied Basic Research Foundation of Yunnan Province, China
Postgraduate Research and Innovation Foundation of Yunnan University
Subject
Geology,Geotechnical Engineering and Engineering Geology
Reference49 articles.
1. Andra’s feasibility study on deep geological disposal of high-level long-lived radioactive waste;Su;Chin. J. Rock Mech. Eng.,2006
2. A review of self-sealing characteristics of clay rocks under coupled thermo-hydro-mechanical conditions;Chen;Chin. J. Rock Mech. Eng.,2019
3. On the surrounding rock of high-level radioactive waste geological repository;Wang;World Nucl. Geosci.,2006
4. Relating the Cation Exchange Properties of the Boom Clay (Belgium) to Mineralogy and Pore-Water Chemistry;Frederickx;Clays Clay Miner.,2018
5. How rock samples can be representative of in situ condition: A case study of Callovo-Oxfordian claystones;Conil;J. Rock Mech. Geotech. Eng.,2018