Geothermal monitoring using DFOS

18 Aug 2021

The use of geothermal energy is an important future energy supply issue within the global strategy of sustainable development. Water and/or steam carry the geothermal energy to the Earth’s surface. Depending on its characteristics, geothermal energy can be used for heating and cooling purposes or be harnessed to generate clean electricity.

geothermal fiber optics electricity

Geothermal reservoirs offer unique monitoring and characterization challenges. One of the serious problems with the use of geothermal water/steam is changes in temperature and pressure. It influences the equilibrium and leads to the scale formation on the wall surface of wells, flow lines, valves, turbines, etc. The harsh, high temperature downhole environment requires robust measurement technology with advanced features. And this is where fiber optic sensors can be utilized as a helpful tool for the application in geothermal wells! Remote operation, small sizes and robust design are being of particular importance and among the inherent advantages.

Over the past decade DFOS has evolved from a new to a prominent geophysical tool with still ever-expanding applications. This is extremely useful to measure continuous temperature and pressure profiles in the subsurface for geothermal exploration. Both DTS and DAS, and even DSS features can be integrated into a single cable design and conduct multiple fully independent measurements simultaneously thus providing independent data for the same perturbation. Using the same design and one time installation for acquisition of different data brings economic benefits for the operators.

Data received from fiber optic sensors can be used in defining the intensity of the thermal anomalies and setting a long-term monitoring system that enables transferring geothermal energy more effectively.

Among the designs offered by Wires&Bytes SensoWire, SlickLight and MultiSense can be used for geothermal monitoring. SensoWire is more traditional and suitable for DTS and DAS applications whereas MultiSense and SlickLight are more innovative and raising significant interest in the industry, providing various asset health monitoring applications. In terms of geothermal monitoring MultiSense can be exploited for acoustic, seismic and well structural health monitoring using its DSS feature (to monitor the integrity of the wells). Currently MultiSense is being deployed and trialed in the geothermal well in Germany. Stay tuned for updates!