A Study on the Differences of Mechanical Properties between CH₄ and CO₂ Hydrate-Bearing Sediments

Abstract:

The CH₄-CO₂ replacement method to recover CH₄ from hydrate-bearing sediments has received great attention because it enables the long term storage of CO₂ and is expected to maintain the stability of gas hydrate-bearing sediments. This paper extends our previous study of the stability of CH₄ hydrate-bearing sediments to CO₂ hydrate-bearing sediments to evaluate the safety of the CH₄-CO₂ replacement method. Low temperature, high pressure triaxial compression apparatus was used to measure the mechanical properties of CO₂ hydrate-bearing sediments. The triaxial tests results for CH₄ and CO₂ hydrate-bearing sediments were then compared. It was found that the failure mode of both the CO₂ and CH₄ hydrate-bearing sediments was a bulging deformation at mid-height on the samples. Moreover, the stress-strain curves of both the CO₂ and CH₄ hydrate-bearing sediments appear to be hyperbolic in shape, and could be divided into three stages: the quasi-elastic stage, the hardening stage and the yield stage. However, the strength of the CO₂ hydrate-bearing sediments was approximately 15% larger than that of the CH₄ hydrate-bearing sediments under the same conditions. The results imply that the stability of gas hydrate-bearing sediments could be maintained using the CH₄-CO₂ replacement method to recover CH₄ from these sediments.

• Periodical: Applied Mechanics and Materials (Volumes 353-356)
• Pages: 1240-1244
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.353-356.1240
• Online since: August 2013
• Authors: Yuan Luo, Yong Chen Song, Wei Guo Liu, Jia Fei Zhao, Yun Fei Chen, Zhi Tao Shen, Chong Ming Ji
• Keywords: Carbon Dioxide Storage, CH₄-CO₂ Replacement, Hydrate, Strength, Triaxial Compression

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