Re-injection of the fluid is more difficult than expected
Reinjection of geothermal fluid is a challenge, notably in clastic environment. Specific developments or well stimulations might be needed throughout the geothermal system lifetime to improve injectivity and corrective measures might be required to maintain acceptable injectivity index (e.g. well cleaning, back-washing, stimulation, etc.)
Informations
- Category: Risks due to subsurface uncertainties
- Id: D-16
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Phases:
- Drilling / Testing
- Exploitation / Development
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Consequences:
- Economic / Performance / Acceptability
Mitigation
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Prevention:
- Regular logging and maintenance of the reinjection well
- In case of porous sandy aquifers use of underreaming and gravel pack in the production section
- Use of killing agent to inhibit bacteria invasion in active layers of the injection well
- Regular cleaning of injection well
- Test duration should be long enough to optimize and sustain exploitation conditions
- Choice a posteriori of the injector well (if possible, depending on well architecture)
- Stop and start exploitation with care to avoid water hammer (that can cause particle matter movement)
- Adequate filtering of the re-injected water
- Best practices for well desgin, completion design and development of well
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Monitoring:
- Monitoring of change of produced water's particle content
- Monitoring of scaling potential of the produced fluid
- Thorough geologicals survey/core sample analysis
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Corrective measures:
- Adapt the power plant design under given temperature/pressure
- Adaptation of the drillpath to reach multiple targets
- Clean well
- Filtration unit at surface
More information is available on the project deliverable (link), or navigate on the online version.
