Wireless downhole monitoring system provides long term aquifer surveillance

Customer Challenges

• Teréga operate an onshore gas storage facility, which plays a key role in the local energy distribution in France
• To comply with local regulations, continual monitoring of the underground gas storage wells is required
• Pressure and temperature readings monitor the fluid levels during injection and production from the acquifer to assist with seasonal demand
• The wells did not have any permanent gauges installed and deploying slickline memory gauges require frequent interventions.   Memory gauges only provide access to historic data, preventing the real-time optimisation of the gas storage process
• Deploying a retrofittable wireless gauge system is an attractive solution to manage these reservoirs most effectively

Expro Excellence

• CaTS gauges were retrofit into 10+ wells on slickline and hung off in standard nipple profiles
• Reservoir P&T are measured using a precision, high resolution, quartz pressure sensor and the data then transmitted to the surface wirelessly
• At the surface, the CaTS receiver collects, decodes and stores the data to local memory
• The surface receivers are powered by batteries, which are charged by solar power.  There is no need for a mains power supply at the well site
• The gauges were installed in 2007, and the systems still provides reliable data through scheduled battery changes.  In 2017 the downhole gauges and surface receivers were upgraded
• Multiple gauges have been installed at different depths in the same well and various wells have been connected to a single topside receiver.  This demonstrates system adressability
• The gauges are recovered every three years for battery replacements and the re-deployed, providing extended monitoring periods. The use of the same CaTS gauges in multiple wells demonstrates the durability of the equipment

Value to Client

• More than 13 years and 1,000,000 hours of continuous, real-time pressure and temperature monitoring across multiple wells at the facility
• Compliance with local data reporting regulations
• Cost savings compared to frequent memory gauge survey runs
• Flexibility to retrieve and re-deploy the gauges to meet the needs of the subsurface surveillance strategy
• Push-button interface on the surface receivers allow the client to download the data when required
• Uninterrupted Power Supply for the surface receivers to ensure gauge data is continuously captured
• Solar powered receivers for remote locations
• System upgrades in 2017 reduced routine service and maintenance visits from 3 per year to 1 visit every 3 years
• 24/7 support and remote assistance provided by WWS
• Excellent relationship developed with the customer
• Gas storage will be an important enabler for the energy transition since simple cycle and combine cycle gas turbines are a cost-effective means of backstopping the variable electricity output of intermittent renewables

Contact

For further information, please contact wireless@expro.com.