Measures to Mitigate the Risk of Explosions in Depleted Gas Reservoirs
Measures to mitigate the risk of explosions in depleted gas reservoirs focus on controlling flammable gas concentrations, monitoring conditions, and implementing protective systems. Key strategies include:
Purging and Gas Composition Control
- Purge the reservoir before use: The reservoir should be depleted of natural gas to the greatest extent practical, using flushing or air cycling below the flammability limit to dilute natural gas concentrations and reduce ignition risk.
- Control of oxidant concentration (inerting): Reducing the oxygen level in the reservoir by inerting prevents the conditions necessary for combustion and explosions.
Monitoring and Detection
- In-situ gas monitors: Installation of downhole gas monitors provides near-source detection of natural gas presence, enabling timely response if flammable concentrations develop.
- Surface gas monitoring: Monitoring natural gas content entering surface equipment helps adjust operational parameters such as the air-fuel ratio in turbines to mitigate explosion risk.
Physical and Mechanical Protection
- Prevent surface breaches and venting: Design the storage and surface equipment to avoid any breaches or venting of hot combustion gases in case of ignition, ensuring containment of any explosion within the reservoir.
- Explosion isolation systems: Use rapid-action valves and chemical explosion blocking systems to prevent flame propagation to other equipment and occupied areas.
- Explosion venting and suppression: Install explosion suppression or venting devices to relieve pressure safely and prevent catastrophic failure of equipment connected with the reservoir.
Ventilation and Dilution
- Ventilation measures: Remove or dilute flammable components such as combustible gases or dusts in associated surface systems to keep concentrations below flammable limits.
Together, these measures—reservoir purging, continuous gas monitoring, inerting to control oxygen levels, structural protections like isolation valves, and ventilation—form a comprehensive approach to explosion risk mitigation in depleted gas reservoirs, particularly when these are used for purposes like compressed air energy storage or gas cycling.
Original article by NenPower, If reposted, please credit the source: https://nenpower.com/blog/what-measures-can-be-taken-to-mitigate-the-risk-of-explosions-in-depleted-gas-reservoirs/
