Pressure challenge in gas storage wells

Underground storage (UGS) wells help store natural gas and reduce the risk of interrupted delivery and service. Often these wells are in depleted gas reservoirs into which gas from other sites has been injected. They must tolerate high injection pressures, high production rates, and frequent changes in temperature and pressure—and still produce gas fast enough to meet peaks in demand.

Maximizing the efficiency of existing gas resources requires that the storage capacity in these reservoirs also be maximized, mainly through an increase in storage pressure. Putting more gas in existing storage areas causes the pressure to increase above customary levels. When these levels are exceeded, the pressure must be carefully monitored to ensure that no leaks or other damage to the storage system occurs.

In Italy, where constant downhole pressure monitoring of UGS wells is required by law, an operator needed to install a highly reliable pressure gauge system that could withstand the high pressures and that would not need to be replaced.

Complete metrology redundancy from hybrid monitoring system

Because of its impressive track record with permanent downhole gauges, Schlumberger was asked to provide a reliable monitoring system that would take continuous downhole temperature and pressure measurements while also providing metrology redundancy.

Increased confidence in pressure readings and safety

By combining the different types of sensors, which had totally different modes of functionality yet similar metrology, the operator had greater confidence in its monitoring and control of the reservoir's pressure and analysis of reservoir behavior trends. As a result, the operator was confident that the gas storage facility was being run within its locally allowed pressure limits and knew that peak gas demand would be met. The operator ordered 11 additional WellWatcher Neon DTS, DAS, and PT gauge systems for its UGS wells.