Natural gas use is seasonal, especially in northern states, which depend on it for heating through the cold and snow of winter. To ensure that adequate supplies of natural gas are available during winter storms, companies that produce and distribute natural gas use large underground storage pools or fields to hold large volumes of natural gas at elevated pressures.
In these storage facilities, corrosion monitoring and mitigation is essential for ensuring safe operation and reliable natural gas supplies.
Effective corrosion coupon exchange methods are critical
For instance, after an acquisition, a key company in the exploration, production, gathering, transmission and storage of natural gas was looking for a corrosion monitoring and mitigation program for its newly acquired storage pool. A major component of the program was the use of corrosion coupons for corrosion monitoring. These coupons are exchanged periodically and evaluated – and exchanging these coupons safely and efficiently is critical.
Corrosion monitoring and mitigation is essential for ensuring safe operation and reliable natural gas supplies.
When an initial evaluation of the corrosion monitoring systems already in place was performed, it was learned that access fitting-type coupon holders were used – but unfortunately, no service valve or retrieval tool was part of the equipment included in the acquisition. Purchasing a new service valve and retrieval tool to maintain the corrosion monitoring and coupon exchange program would be no small expense.
Costly coupon exchange provides lesson
After acquiring the new valve and tool, the company’s team began the coupon exchange at the company’s 12 coupon locations. A two-man crew was required for the operation due to weight and complexity of operating the service valve and retrieval tool. The team soon ran into operational problems, requiring a rebuild of the service valve and retrieval tool – which meant the coupon exchange then required three days to complete.
After this painful experience was repeated during a subsequent coupon exchange, the facility manager decided to investigate other corrosion coupon insertion methods and contacted Jason Rine, Director, MSES Corrosion Products Division, who has extensive experience in providing corrosion monitoring and measurement solutions to oil and gas companies in the Appalachian Basin.
New corrosion monitoring system increases efficiency and safety
Due to experience, Rine knew the corrosion coupon exchange process could be handled more easily, quickly and cost-effectively with Sentry® corrosion monitoring solutions. He recommended installing a Sentry internal access fitting adapter, an isolation ball valve and a Sentry Saf-T-Vise™ MM-30 coupon holder, ideal for monitoring and protecting high-pressure applications. A single, lightweight but durable Sentry HPT insertion tool could be used to easily service all the coupon locations without interruption of the system, and required only one person to operate it as well as minimal clearance space (other systems require clearances of up to two-and-a-half times the height of the tool).
The company made the change at the end of the heating season. Each installation point needed to be blown down prior to removing the old coupon holder, then repressurized after the Sentry coupon holder and accessory components were installed. Even with those additional steps, all 12 coupon location points were changed over in only five hours, and the company has conducted the coupon exchange process twice since then without issue.
Corrosion coupon retrieval now faster, easier
The Sentry Saf-T-Vise MM-30 coupon holder and HPT insertion tool together make exchanging coupons faster and easier, while ensuring operator safety. Because the insertion tool safely can be operated by only one technician, the company is able to make the coupon exchanges with only one-eighth the manpower labor hours the access fitting system required, while addressing operator safety concerns – and eliminating rebuilds after every exchange.
With innovative designs and cost-effective and safe operation, Sentry corrosion monitoring & chemical injection products offer ease of use and custom configuration for maximum versatility. They can be fitted with corrosion coupon holders, chemical injection atomizers, or chemical injection & sample quills for high- or low-pressure applications.
Thank you to Jason Rine for application information.