Surface subsidence or uplift
Geothermal operation may cause ground surface deformation. Commonly, the ground surface subsides/lowers because of geothermal fluids extraction, conversely, re-injection of geothermal fluids can induce ground uplift. In both cases, the surface deformation is generally caused by pressure and/or temperature changes within the geothermal reservoir. Surface deformation associated with geothermal field utilization, when it occurs, is usually in the order of mm/yr to cm/yr and generally presents low risk. Swellings can appear when drilling in sensitive geological context where anhydrites, saline or gypsum formation are encountered as they can react when in contact with water and cause surface deformations. Ref Geoenvi D2,1.
Informations
- Category: Environmental risks
- Id: F-4
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Phases:
- Drilling / Testing
- Exploitation / Development
- Post-closure
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Consequences:
- Health / Safety / Environment
Mitigation
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Prevention:
- Avoid high re-injection pressure/rate
- Thorough reservoir management plan ( e.g. thermal fluid re-injection)
- Reinjection of the fluid produced in the formation
- Prediction modeling of reservoir performance and stress modifications considering geomechanical rock properties
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Monitoring:
- Monitoring of ground surface deformation using satellite systems (InSAR, GNSS)
More information is available on the project deliverable (link), or navigate on the online version.
