dsd-int 2016 from regional model to local imod model and back - panteleit
TRANSCRIPT
G D f B
Geologischer
Dienst f ü r Bremen
G D f B
Geologischer
Dienst f ü r 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)
G D f B
Geologischer
Dienst f ü r Bremen
G D f B
Geologischer
Dienst f ü r 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
G D f B
Geologischer
Dienst f ü r Bremen
G D f B
Geologischer
Dienst f ü r 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
G D f B
Geologischer
Dienst f ü r Bremen
G D f B
Geologischer
Dienst f ü r 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
G D f B
Geologischer
Dienst f ü r Bremen
G D f B
Geologischer
Dienst f ü r 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)
G D f B
Geologischer
Dienst f ü r Bremen
G D f B
Geologischer
Dienst f ü r 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
iMOD MODFLOW
G D f B
Geologischer
Dienst f ü r Bremen
G D f B
Geologischer
Dienst f ü r 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)
G D f B
Geologischer
Dienst f ü r Bremen
G D f B
Geologischer
Dienst f ü r 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
G D f B
Geologischer
Dienst f ü r Bremen
G D f B
Geologischer
Dienst f ü r 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