UNDERGROUND ENERGY STORAGE MONITORING
OVERVIEW
Downhole pressure, temperature and vibration monitoring of gas (UGS), hydrogen energy (HES), and compressed-air energy (CAES) storage wells provide operators with the basis for accurate material balance, fluid level calculations and tubing stability. Governments are increasing regulatory demands for the monitoring of underground energy storage volume and pressure, and confirmation of caprock integrity on a frequent and long-term basis.
Acoustic Data’s SonicGauge™ Wireless Monitoring System allows cost-effective regulatory compliance by providing a high accuracy and high resolution wireless downhole gauge to measure pressure trends to identify the smallest deviation from expected subsurface storage pressure. Additionally, the SonicGauge™ System dynamically measures injection and production pressure gradients when SonicRepeater stations are equipped with onboard pressure transducers deployed at strategic locations along the tubing string.
Injection and production rates can be large and induce tubing oscillation. Along with pressure and temperature data packets, the SonicGauge™ can report highly sensitive vibration parameters in real-time, allowing the operator to safely manage injection and withdrawal rates.
The SonicGauge can be quickly retrofitted on slickline using the Barracuda™ HEX-Hanger™ (high expansion gauge hanger) in monitoring wells with tubing sizes from 2-3/8” to 13-3/8”, offering a rig-less deployment option. The technology can be set virtually anywhere in the tubing string by the patented and battery-powered Electro-SET (electro-mechanical setting tool).
The SonicGauge functions on an ultra-low energy budget and can provide real-time surface-read-out (SRO) of data for up to 8 years without well intervention, thus reducing operational expenditure and risk for years at a time.
APPLICATIONS
BENEFITS

CASE STUDY 1 | EUROPEAN OPERATOR
The SonicGauge™ Wireless Monitoring System reduces well intervention activity and OPEX across a six-year period with a single slickline run
TECHNOLOGIES
CHALLENGE
Underground Gas Storage (UGS) operators use depleted gas reservoirs to store natural gas during off-peak periods to have reserves to pump back into the gas transport system during periods of high seasonal demand. They monitor the volumes stored on a regular basis by interpreting pressure and temperature measurements taken inside the reservoir.
The client sought a cost-effective single gauge solution to monitor real-time downhole pressure and temperature data in a key well over a multi-year duration to replace sporadic and costly memory gauge runs.
SOLUTION
Acoustic Data retrofitted a turnkey SonicGauge™ Wireless Monitoring System in a single slickline run. The SonicGauge Sensor was set in 7” tubing at a depth of 925m (3,034ft) on the Barracuda™ HEX-Hanger™ and was able to transmit real-time downhole pressure and temperature to surface in a single hop.
The Barracuda system is not reliant on nipple profiles for installation, allowing the SonicGauge to be located at the exact depth the client required. When the battery-powered Electro-SET (electro-mechanical setting tool) was recovered to surface, the onboard data logs confirmed that the HEX-Hanger had been successfully set.
Post-installation, P&T data was displayed on the SonicGauge Data Logger (SDL) and patched into the customer's distributed control system (DCS) via the Modbus communication port.
Two real-time P&T data points per day will be acquired for the planned system life of six years. After which, the downhole SonicGauge System will be retrieved, redressed, reprogrammed, and rerun for another six years.
RESULTS

CASE STUDY 2 | EUROPEAN OPERATOR
The SonicGauge™ Wireless Monitoring System retrofitted via slickline to Underground Gas Storage well to provide multi-year downhole data acquisition
TECHNOLOGIES
CHALLENGE
Underground Gas Storage (UGS) operators use depleted gas reservoirs to store natural gas during off-peak periods to have reserves to pump back into the gas transport system during periods of high seasonal demand. They monitor the volumes stored on a regular basis by interpreting pressure and temperature measurements taken inside the reservoir.
The client sought a cost-effective method to monitor real-time downhole pressure and temperature data in a key well over a multi-year duration to replace sporadic and costly memory gauge runs. The system had to provide data during flow, high-pressure injection and shut-in periods.
SOLUTION
Acoustic Data retrofitted a turnkey SonicGauge™ Wireless Monitoring System in two slickline runs on the Barracuda™ HEX-Hanger™ system. The SonicGauge Sensor and SonicGauge Repeater were set in 7” tubing at depths of 925m (3,034ft) and 400m (1,312ft), respectively.
The high-expansion Barracuda technology is not reliant on nipple profiles for installation and allowed the SonicGauge System to be located at the exact depths required by the client. When set inside the tubing, real-time downhole pressure and temperature (P&T) data was immediately available at surface.
When the battery-powered Electro-SET™ (electro-mechanical setting tool) was recovered to surface after each run, the onboard data logs confirmed that the HEX-Hangers were successfully set.
Real-time P&T data was displayed on the SonicGauge Data Logger (SDL) and patched into the customer's distributed control system (DCS) via the Modbus communication port.
RESULTS

CASE STUDY 3 | EUROPEAN OPERATOR
Two SonicGauge™ Wireless Monitoring Systems successfully retrofitted in 2-3/8” tubing to reduce long-term OPEX while complying with local UGS monitoring regulations
TECHNOLOGIES
CHALLENGE
The client sought a cost-effective method to monitor downhole pressure and temperature data in real-time over a multi-year duration to replace sporadic and costly memory gauge runs.
SOLUTION
Acoustic Data retrofitted two SonicGauge™ Wireless Monitoring Systems in a 2-3/8” dual-string completion on the Barracuda™ HEX-Hanger™ technology via slickline, circumventing the requirement for nipple profiles and restrictive tubing stops.
The SonicGauge Sensor and SonicGauge Repeaters in string-1 were set in 2-3/8” tubing at depths of 1,935m (6,346ft), 1,300m (4,264ft) and 600m (1,968ft), respectively. In string-2, the tools were located at 1,925m (6,315ft), 1,298m (4,259ft), 850m (2,789ft) and 450m (1,476ft).
A slimline (1.87” OD) Barracuda™ Electro-SET™ was used to pass through 2-3/8” nipple profiles and set the tools inside the tubing. Real-time downhole pressure and temperature (P&T) data was immediately available at surface and viewed at Acoustic Data headquarters via the 4G-WiFi communication system.
The data acquisition schedule was initially programmed at 10-minute transmission intervals providing a downhole gradient survey along the well completion through the SonicGauge Repeaters equipped with onboard pressure transducers.
The schedule then transitioned to 1-hourly intervals to provide dynamic injection and production pressure gradients for two years. After which, the SonicGauge System will be retrieved, redressed, reprogrammed and rerun.