Jump to main content
Jump to site search

Issue 5, 2020, Issue in Progress
Previous Article Next Article

Microscopic investigations on the healing and softening of damaged salt by uniaxial deformation from CT, SEM and NMR: effect of fluids (brine and oil)

Author affiliations

Abstract

Nowadays, a salt cavern, used as underground energy storage (e.g. natural gas, crude oil, hydrogen), is becoming more and more popular in China due to its many advantages, such as low permeability (≤10−21 m2), good water-soluble mining and the damage-healing characteristic of salt rocks. It not only solves the problem of energy resource supply-demand imbalance in China, but also provides a better, more secure and cost-effective way to store energy compared to aboveground energy storage systems. As for salt cavern storage, permeability is our primary concern in engineering, which is mainly influenced by damage and healing. In this work, some damaged salt specimens were prepared by uniaxial compression tests (the loading rate was 0.033 mm s−1). Then those specimens were immersed in either a saturated brine solution or oil at 50 °C for a few days. Microscopic investigations were carried out by X-ray Computed Tomography (CT), Scanning Electron Microscope (SEM) and Nuclear Magnetic Resonance (NMR) to investigate the change of salt microstructures after healing. Possible micro-healing mechanisms were discussed. It was found that fluids played an important role in the healing process of damaged salt. Healing effectiveness of micro-pores and -cracks with the brine solution was higher than that with oil mainly because of crystal recrystallization. The surface of the grains was smooth and had no visible microcracks after healing in brine, while there were many pits and micro-tunnels with oil. Oil could hinder the healing process by impeding the diffusion effect and restraining grain recrystallization. Meanwhile, intragranular and intergranular water could also work as a lubricant resulting in softening which made salt rock more deformable. NMR results confirmed that damaged salt had a better recovery with brine, displaying lower porosity and lower permeability compared to that with oil. This work provides preliminary microscopic investigations on the healing of damaged salt in order to reveal the salt healing mechanism.

Graphical abstract: Microscopic investigations on the healing and softening of damaged salt by uniaxial deformation from CT, SEM and NMR: effect of fluids (brine and oil)

Back to tab navigation

Article information


Submitted
29 Jul 2019
Accepted
06 Jan 2020
First published
16 Jan 2020

This article is Open Access

RSC Adv., 2020,10, 2877-2886
Article type
Paper

Microscopic investigations on the healing and softening of damaged salt by uniaxial deformation from CT, SEM and NMR: effect of fluids (brine and oil)

J. Chen, H. Peng, J. Fan, X. Zhang, W. Liu and D. Jiang, RSC Adv., 2020, 10, 2877
DOI: 10.1039/C9RA05866D

This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence. Material from this article can be used in other publications provided that the correct acknowledgement is given with the reproduced material and it is not used for commercial purposes.

Reproduced material should be attributed as follows:

  • For reproduction of material from NJC:
    [Original citation] - Published by The Royal Society of Chemistry (RSC) on behalf of the Centre National de la Recherche Scientifique (CNRS) and the RSC.
  • For reproduction of material from PCCP:
    [Original citation] - Published by the PCCP Owner Societies.
  • For reproduction of material from PPS:
    [Original citation] - Published by The Royal Society of Chemistry (RSC) on behalf of the European Society for Photobiology, the European Photochemistry Association, and RSC.
  • For reproduction of material from all other RSC journals:
    [Original citation] - Published by The Royal Society of Chemistry.

Information about reproducing material from RSC articles with different licences is available on our Permission Requests page.


Social activity

Search articles by author

Spotlight

Advertisements