3D Geological Modelling at BRGM

05/06/2008

3D Geological Modelling at BRGMC. Truffert

BGR-GeoEurope3D – 5th June 2008

GeoEurope3D : modelling at BRGM; BGR meeting, June 2008 > 2

3D Geological Modelling at BRGM

1. Main axis and application fields of 3D geological modelling in BRGM

2. Softwares and methods

3. Examples of applications

4. Projects in R&D


3D Geological Modelling at BRGM 1. Two main axis

> Applications• Construction of 3D

geological models (geometry + properties)

• Models are often the input for the simulation of a process (water or CO2 flow, seismic, …)

> Research• Development of geological

modelling softwares


> Basic geology knowledge (regional / local scale)

> Aquifer inventory; input model for flow simulation

> Urban geology

> Seismic risk

> Engineering projects (tunnel / mineral water …)

> Assessment of CO2 storage capacity

> Assessment of geothermal potential

3D Geological Modelling at BRGM 1. Application fields






4. Projects in R&D


4 Main tools used :

> Layer-cake geometry, many data• GDM + MULTILAYER

> Complex geometry, true 3D objects, geophysical inversion• GEOMODELLER

> Complex geometry and fault network• EARTH VISION (commercial software)

> Petrophysical properties, facies, 3D simulations• ISATIS (commercial geostatistical software)

3D Geological Modelling at BRGM 2. Softwares & methods

« home made » Methodologies and softwares


GDM + MULTILAYER SOFTWARES

> Layer-cake geometry, faults considered as vertical

> 2D geostatistical interpolation• Top, bottom or thickness of a layer

> Data: boreholes, full geological map, cross sections, 3D passage points• Several thousands of data points can be taken into account

> Main advantages• Full set of data consistency checks (hole-DEM, hole-hole, hole-geological map,

histogram, geostatistical cross validation) • Stratigraphic pile• 3D Constraint points digitized on 2D maps or cross sections (in GDM)• Automatic contour maps (with scale, axis, …), logs• But no direct 3D visualisation• export of result grids to other softwares (Arcview, Mapinfo, EarthVision)



> Complex 3D geometry; geophysical inversion

> 3D potential field interpolation• A geological interface is a particular isovalue V0 of a 3D field V=f(X,Y,Z)

> Data: boreholes, points from the geological map, digitized cross sections, 3D boundaries points + orientation data

(Number of data limited to max 2000 to 3000 per geological unit)

> Main advantages• Very « Easy-to-use » software

• Takes into account structural data

• Complex geology (folds, inverse faults, …)

• Geological pile

• 3D constraint points digitized on 2-D map or cross sections

• True 3D model (geological formation known at every 3D point)

• Full 3D visualisation (surface+volume)

• Geophysical inversion



EARTH VISION SOFTWARE

> Complex 3D geometry and fault network

> Spline type interpolation for layer-cake geometry, or 3D function for 3D objects

> Data: 3D passage points from boreholes, geological map, digitized cross sections, seismic data

> Main advantages• complete software, automatic fault throw re-construction• geological pile• Constraint points digitized in 3D• 3D visualisation (surface+volume)• Time/Depth conversion• But more difficult to use, does not handle inequalities, expensive• More adapted for oil-industry data (many seismic, few holes)



ISATIS SOFTWARE

> Simple or complex 2D-3D geostatistics

> 2D-3D Interpolation (geometry or rock properties)

> 2D-3D Simulation (facies simulation, pixel-based methods or object-base methods)

> Main advantages• Includes nearly all geostatistical functions

• 3D visualisation (surface+volume)

• But need of good geostatistical knowledge







4. Projects in R&D


> Basic geological knowledge

3D Geological Modelling at BRGM3. Examples

Paris Basin (MultiLayer) Champtoceaux, Laragne (GEOMODELLER)


> Basic geological knowledge• Marine geology (GEOMODELLER)

Pre-Pliocene Geological Map(Isochronic map of the

Messinian erosion surface)

Understand relationships between the Messinian phase and the regional tectonic context

Describe the markers of the Messinian Salinity Crisis in the marginal basin

Main objectives :



> Aquifer inventory / input model for flow simulation

Infra-Toarcian aquiferPoitiers region

MultiLayer

Model of SAQ aquifersSaudi ArabiaEarthVision



> Seismic risk• Suva (Fiji, 2000) : Geometry (GDM)

• Nice (France, 2002) : Geometry (GEOMODELLER)

Nice model (alluviums) : model used to simulatethe ground behaviour during a seismic event



> Urban Geology• Lyon (2000) : Geometry (GDM) + 3D flow simulation

• Bordeaux (2006) : Geometry (GDM+ISATIS); Geotechnical and hydrogeological properties (ISATIS)

3D probability map of being in a low permeability terrainin the alluviums of a sector of Bordeaux citySize of model: approx 7 km * 6 km * 15 m



> Engineering projects• France-Italy Fast-Train Tunnel (2005):

Geometry (GEOMODELLER, figs.)

• Mineral water (2007): Geometry (GEOMODELLER) + double phase flow simulation



> Assessment of CO2 storage capacity • Dogger in Paris Basin : geometry (EARTHVISION)

• Dogger in Paris Basin: facies and flow properties (ISATIS)

• CO2Net project

Permability modelin cross stratified sanstone,used for CO2 flow simulation

(Cmos software – GEUS)



> Geothermal Potential• Limagnes basin (2005) : Geometry (GEOMODELLER) – volume

calculation

• Paris Basin (2007) : 3D temperature field (ISATIS)







4. Projects in R&D


3D Geological Modelling at BRGM 4. Projects in R&D

> Improving construction of models• More data in Geomodeller

• MultiLayer functions in Geomodeller software

• More realistic geological models

• Improve imports and exports

• Improve geophysical inversion

• Faster algorithms and automatic workflows

> Links with further processing• Develop appropriate meshers

> Models + metadata available on the web• Public

• Geo-scientists, …


3D Geological Modelling at BRGM 4. Projects in R&D

> Final objective: to give the geologist an integrated interface on his PC, enabling :• search and display available data (drill holes, geol maps …)

• download + pre-process this data

• build a geometrical model

• mesh this model according to the final objective of the work

• populate the meshes of the model with the appropriate properties

• simulate a physico-chemical process in this model

• display results in 1D, 2D, 3D, 4D …

> Web server for models and results


3D Geological Modelling at BRGM - Conclusion

> BRGM is involved in 3D geological modelling since 10 years

> 3D modelling is the key issue for geology and forward applications (ground-water, risk assessment, land-use, mineral resources and oil exploration …)

> Continue Research & Developpement are needed to implement a workflow from data acquisition to 3D dynamic modelling

> Different 3D modelling softwares are needed

3D Geological Modelling at BRGM

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