Modeling of Short-Term Stimulation and Long-Term Operation of EGS - - PowerPoint PPT Presentation

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Modeling of Short-Term Stimulation and Long-Term Operation of EGS - - PowerPoint PPT Presentation

Nov 18, 2023 157 likes •237 views

Modeling of Short-Term Stimulation and Long-Term Operation of EGS Reservoirs T. Kohl & T. Mgel GEOWATT AG Dohlenweg 28, CH-8050 Zrich Contents Investigation of the dynamic response of an "Enhanced Geothermal Systems" to

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Modeling of Short-Term Stimulation and Long-Term Operation of EGS Reservoirs

  • T. Kohl & T. Mégel

GEOWATT AG Dohlenweg 28, CH-8050 Zürich

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Contents

Investigation of the dynamic response of an "Enhanced Geothermal Systems" to forced injection of cold fluid Individual processes (pressure, temperature and stress) result in specific time-constants. Extending the evaluation can usually only be carried out by numerical modeling

  • Deterministic reservoir models
  • Stochastic reservoir models

H-T-M evaluations calculated with the simulators FRACTure and HEX-S (identical FE kernel)

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Experience on deterministic H-T-M simulations

X Y

r 30 years

3D Reservoir

4 fracture zones Poro-Elasticity & Thermo-Elasticity (Kohl, 1995) Normal aperture compliance No shearing

  • > not suited for hydraulic stimulation

Temperature S22 stress change

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3D- Deterministic Fracture Geometry Dynamic Long Term Behaviour

Synthetic example aperture: a0=200µm t=10yrs t=30yrs

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Situation after 30 years ∆T [K]

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Situation after 10 years

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Darcy-velocity 1 m s

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2.5E-04 2.4E-04 2.3E-04 2.2E-04 2.1E-04 2.0E-04

aperture [m]

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Example: Simulation GPK4 Development of aperture (≅permeab.)

2.7 h 5 h 20 h 36 h 53 h Iso-Surface = 0.0001 m

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Y X Z

1.70E+07 1.60E+07 1.50E+07 1.40E+07 1.30E+07 1.20E+07 1.10E+07 1.00E+07 9.00E+06 8.00E+06 7.00E+06 6.00E+06 5.00E+06 4.00E+06 3.00E+06 2.00E+06 1.00E+06

Reservoir Pressure Distribution

Flow aligned along seismic structures Seismicity connected to zones of high pressure

Simulated shearing events & pressure distribution GPK3

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Forecast GPK4 stimulation: HEX-S Hydraulic Model

Predicted evolution of shearing events at GPK4 after 1 day stimulation Plane View

Events are not location-corrected

View from West

Path of development