Abstract
Salt deposits are commonly regarded as ideal hosts for geologic energy reservoirs. Underground cavern construction-induced damage in salt is reduced by self-healing. Thus, studying the influencing factors on such healing processes is important. This research uses ultrasonic technology to monitor the longitudinal wave velocity variations of stress-damaged rock salts during self-recovery experiments under different recovery conditions. The influences of stress-induced initial damage, temperature, humidity, and oil on the self-recovery of damaged rock salts are analyzed. The wave velocity values of the damaged rock salts increase rapidly during the first 200 h of recovery, and the values gradually increase toward stabilization after 600 h. The recovery of damaged rock salts is subjected to higher initial damage stress. Water is important in damage recovery. The increase in temperature improves damage recovery when water is abundant, but hinders recovery when water evaporates. The presence of residual hydraulic oil blocks the inter-granular role of water and restrains the recovery under triaxial compression. The results indicate that rock salt damage recovery is related to the damage degree, pore pressure, temperature, humidity, and presence of oil due to the sealing integrity of the jacket material.
Highlights
Rock salt is one of the potential host rocks for storage of oil and natural gas
We investigated the dependence of the damage variation of rock salt damage on recovery time, stress-induced initial damage, temperature, and oil, which is significant for the stability of salt caverns affected by rock salt damage and recovery
Analysis of the Self-Healing Ability of Damaged Rock Salt In Figure 2, the stress-induced initial damage of halite specimen is given in a normal temperature environment, and separately, at 50 °C and 70 °C constant temperatures and humidity
Summary
Compared with other surrounding energy-storing rock masses underground, rock salt is characterized by low porosity and permeability, good creep properties, damage self-healing, and large plastic deformation capacity [1,2]. Geotechnical barriers must be constructed for sealing drifts and shafts in underground repositories. The excavation disturbed zone with increased permeability constitutes a potential risk to the functionality and effectiveness of the geotechnical barriers [3,4,5]. During the cavern construction period and gas storage process, the salt cavern bears horizontal and vertical stresses from the formation and fluid pressure inside the cavity, resulting in damage and fissure on the side wall of the cavern and an increase in the permeability of the rock salt, which are not conducive for stability and sealing of the salt cavern. Some scholars have conducted related research on damage and self-healing of rock salt as follows
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
