DSD-INT 2016 From regional model to local iMOD model and back - Panteleit
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The document outlines the development of a geological model transitioning from a regional Gocad model to a refined local Imod model, using over 35,000 borehole descriptions. This includes the creation of structural models based on stratigraphic units, the derivation of parameters from lithology, and the implementation of hydraulic modeling without calibration. Additionally, it highlights the importance of model verification and correction to improve the borehole database quality for local projects.
DSD-INT 2016 From regional model to local iMOD model and back - Panteleit
- 1. GDfB Geologischer Dienst f ür Bremen GDfB Geologischer Dienst f ür Bremen Dr. Björn Panteleit Geologischer Dienst für Bremen Leobener Str. marum 28359 Bremen www.gdfb.de From a regional gOcad model towards a local refined iMOD model and back Björn Panteleit Geological Survey of Bremen (GER)
- 2. GDfB Geologischer Dienst f ür Bremen GDfB Geologischer Dienst f ür Bremen Dr. Björn Panteleit Geologischer Dienst für Bremen Leobener Str. marum 28359 Bremen www.gdfb.de Structual model - from the borehole to surfaces 2 • 6 Layer model based on 35.000 borehole descriptions of different quality classes 20- times extended high
- 3. GDfB Geologischer Dienst f ür Bremen GDfB Geologischer Dienst f ür Bremen Dr. Björn Panteleit Geologischer Dienst für Bremen Leobener Str. marum 28359 Bremen www.gdfb.de Structual model - from surfaces to solid grids 3 • Surface base layer to top layer associated by vertical projection of 100 x 100 m cells • Stratigraphic units divided into equidistant layers • continous layer • regular cells • vertical resolution variable 20- times extended high
- 4. GDfB Geologischer Dienst f ür Bremen GDfB Geologischer Dienst f ür Bremen Dr. Björn Panteleit Geologischer Dienst für Bremen Leobener Str. marum 28359 Bremen www.gdfb.de Structual model - parametrisation 4 • parameters are derived from the lithology of boreholes (thermal & hydraulic conductivity) • assigned to the corresponding cells • transfer by interpolation into space 20- times extended high 0 2 4 6 8 10 pKf = -logKf 20- times extended high • Bremerhaven: 250 x 179 cells / 38 layer • Bremen: 350 x 438 cells / 38 layer
- 5. GDfB Geologischer Dienst f ür Bremen GDfB Geologischer Dienst f ür Bremen Dr. Björn Panteleit Geologischer Dienst für Bremen Leobener Str. marum 28359 Bremen www.gdfb.de Structure based hydraulic modeling iMOD FREEWAT MODFLOW • Hydraulic model based on the structural model • Adding Border constrains • No calibration (as kf-values come from the geology)
- 6. GDfB Geologischer Dienst f ür Bremen GDfB Geologischer Dienst f ür Bremen Dr. Björn Panteleit Geologischer Dienst für Bremen Leobener Str. marum 28359 Bremen www.gdfb.de Grid Transfer 1. grid Export as ASCII column based file 2. import into database 3. rearrangement of data & creation of MODFLOW headers at layer breaks 4. export of data to modflow files *.GRD / BCF.dat iMODMODFLOW
- 7. GDfB Geologischer Dienst f ür Bremen GDfB Geologischer Dienst f ür Bremen Dr. Björn Panteleit Geologischer Dienst für Bremen Leobener Str. marum 28359 Bremen www.gdfb.de variance: 1,11 Model verfication 7 • Too low water table in one region of Bremerhaven • Reason: to high transmissivity due to bad borehole descriptions in that area (several meters of gravel)
- 8. GDfB Geologischer Dienst f ür Bremen GDfB Geologischer Dienst f ür Bremen Dr. Björn Panteleit Geologischer Dienst für Bremen Leobener Str. marum 28359 Bremen www.gdfb.de variance: 0,50 Model correction 8 • Correction of the layer descripion (into sand/gravel) • new parameter interpolation / transfer to flow model Results of the flow model helped to improve the quality of the borehole database
- 9. GDfB Geologischer Dienst f ür Bremen GDfB Geologischer Dienst f ür Bremen Dr. Björn Panteleit Geologischer Dienst für Bremen Leobener Str. marum 28359 Bremen www.gdfb.de Refinement for local projects • Verified models are locally refined for projects • Additional cross sections are constructed • Update of the structural model
- 10. GDfB Geologischer Dienst f ür Bremen GDfB Geologischer Dienst f ür Bremen Dr. Björn Panteleit Geologischer Dienst für Bremen Leobener Str. marum 28359 Bremen www.gdfb.de 10