Vancouver, 2006 © 2004 BRGM GeoModeller – Building Better Models … Faster!

Vancouver, 2006 © 2004 BRGM Build from data! Use classical field data … - geology contacts - dip & strike measurements Add data … - build a new model Add a fault … -build a new model Rather than a model being a once-off final product … it becomes dynamic … and can be updated as required

Vancouver, 2006 © 2004 BRGM Topics Challenges GeoModeller Software The interpolator methodology –Simple layered geology –More complex geology Touch on … –Inputs, outputs, geophysics Inversion of magnetics & gravity

Vancouver, 2006 © 2004 BRGM Challenge 1: Change Change a 3D geology model …

Vancouver, 2006 © 2004 BRGM Changing a Geological Model We would like to be able to change models … –new data ? –revised ideas ? Build the model directly from data ? Geological Data Modelled Geological Surfaces

Vancouver, 2006 © 2004 BRGM Challenge 2: Sampling Sampling the geology signal …

Vancouver, 2006 © 2004 BRGM Houston, we have a problem! To communicate an understanding of the geology of an area … I can ‘map’ the area … and produce a geology map ( … I ‘sample’ the ‘geology signal’ !) ??? ??? ??

Vancouver, 2006 © 2004 BRGM Houston, we have a problem! If I stack up the request like this … and make it a 3D challenge … … you can see we have a problem … –and it’s a ‘sampling problem’ –I do not have a good distribution of samples! Lots of sampling here No samples here

Vancouver, 2006 © 2004 BRGM The Solution … Get the samples … or get smarter! Spend lots of money –Drilling … we directly sample the geology Use geophysical datasets … –Indirectly sampling the geology signals Use all available data in smarter ways … –By integrating geology information –Adding a geologist’s interpretive insights –Using tools that assist the geologist’s task

Vancouver, 2006 © 2004 BRGM Design Goals A tool to build a 3D geological model directly from the observed data … and so the ability to add data … … and build a revised model A tool that provides a practical interpretive environment for the geologist … and so makes the geologist’s interpretive skills part of the solution to the under-sampling problem … able to be used by the field geologist to build a practical 3D model

Vancouver, 2006 © 2004 BRGM GeoModeller in a Workflow Context

Vancouver, 2006 © 2004 BRGM Other Processing … GeoModeller’s World Assemble Tools - Maps - Sections - 3D Models Database GIS CAD Tool - Fluid-flow modelling - Thermal modelling - Earthquake simulation Presentation

Vancouver, 2006 © 2004 BRGM Other Processing … Build Model Assemble Tools - Maps - Sections - 3D Models Database GIS CAD Tool - Fluid-flow modelling - Thermal modelling - Earthquake simulation Presentation GeoModeller directly from the data Build Model Query Lines Shapes Query Review Interpret

Vancouver, 2006 © 2004 BRGM Build a Model from the Data

Vancouver, 2006 © 2004 BRGM Geology Stratigraphic Relationships Field Observations

Vancouver, 2006 © 2004 BRGM Using data … build a Model … Stratigraphic succession Geology contacts Geology dip and strike data Faults noted; position and attitude Goal: Build a 3D geology model … … directly from the observed data

Vancouver, 2006 © 2004 BRGM Field Observations Query the Model … predict Geology The model is consistent with the observations that have been recorded … … but there is scope to improve this model by adding more data.

Vancouver, 2006 © 2004 BRGM Additional field mapping … new data

Vancouver, 2006 © 2004 BRGM Add data … and re-build the model Additional geology contact data are now available … –we want to add these observations … –and re-build the model using all data

Vancouver, 2006 © 2004 BRGM Query the re-built Model … The revised model is better, but there is still scope for further mapping and improvement.

Vancouver, 2006 © 2004 BRGM Further revised geology Model Further revised model – still based little data – can be used to predict geology beneath cover and into the third dimension.

Vancouver, 2006 © 2004 BRGM The GeoModeller Workbench

Vancouver, 2006 © 2004 BRGM Data-model-query-review-interpret

Vancouver, 2006 © 2004 BRGM A model … but wait, there’s more

Vancouver, 2006 © 2004 BRGM New Data, New Ideas, New Model

Vancouver, 2006 © 2004 BRGM Summarising so far … Build a model – directly from raw geology observations Actually uses dip and strike data I can ‘query the model’ and view it in 2D and 3D views … consider … re-interpret I can revise my model as new data, new ideas emerge Key Point – I can rapidly test ideas re the 3D structure – see the result of my ideas in a full 3D view. This immediacy of feed-back is critical to the achieving a genuine interpretive environment … to refine or reject my ideas (interpretation)

Vancouver, 2006 © 2004 BRGM GeoModeller’s Interpolator

Vancouver, 2006 © 2004 BRGM Potential Field Method We use the mathematics of potentials! –Smoothly curving, sub-parallel layers of geology in 3D space are analogous to a set of iso-potentials of a scalar (potential) field Interpolation Method

Vancouver, 2006 © 2004 BRGM More Complex Geology? Multiple Interpolators

Vancouver, 2006 © 2004 BRGM A more complex example... How can I obtain this cross-section using a potential field? More Complex Geology

Vancouver, 2006 © 2004 BRGM Geological Observations Understand the rock relationships … and construct the stratigraphic column More Complex Geology

Vancouver, 2006 © 2004 BRGM One Field per Series - 1 Potential of the first series … Iso-value 1 Iso-value 2 Iso-value 3 More Complex Geology

Vancouver, 2006 © 2004 BRGM One Field per Series - 2 Potential of the second series … Iso-value 1 Iso-value 2 More Complex Geology

Vancouver, 2006 © 2004 BRGM One Field per Series - 3 Potential of the third series … Iso-value 1 More Complex Geology

Vancouver, 2006 © 2004 BRGM Combine the Three Potentials More Complex Geology

Vancouver, 2006 © 2004 BRGM Combine the Potentials - OnLap ONLAP: Series F2 stops on Series F1 Why ? More Complex Geology

Vancouver, 2006 © 2004 BRGM Combine the Potentials - Erode ERODE: Series F2 cuts across Series F1 Why ? More Complex Geology

Vancouver, 2006 © 2004 BRGM Onlap / Erode Determines the Model More Complex Geology

Vancouver, 2006 © 2004 BRGM Purnama, Indonesia

Vancouver, 2006 © 2004 BRGM The Language of Geology Intuitive working environment

Vancouver, 2006 © 2004 BRGM Geological Intelligence Strat. order Conformable On-lapping Erosional 2D Sections, 3D Viewer Faults, folds, hinge lines, dip & strike Use the data a geologist can observe in the field The lines are not simply lines that satisfy topological rules (GIS), but rather geological intelligence is built into them Geology

Vancouver, 2006 © 2004 BRGM Faults Can be constrained within specified geology series Can be finite … with decreasing impact towards the limits Can be constrained to stop against specified other faults Geology

Vancouver, 2006 © 2004 BRGM Limited Faults N Geology

Vancouver, 2006 © 2004 BRGM We can define an axial surface … … and create a section-view on that axial surface … and plot the ‘model’ in that section view of the axial surface … We could propose that the ‘hinge line’ should be ‘adjusted’ … Re-compute the model; the fold honours the proposed hinge line. Fold Axial Surface, Hinge Line We can define an axial surface … Geology

Vancouver, 2006 © 2004 BRGM Data Inputs Your geological understanding of stratigraphic order, conformable packages, their rock relationships … Plus … Data from … –Geo-registered images (then digitise) –Import from GIS, ASCII text files –Import drillhole collars, surveys, geology Plus … Your interpretive hypotheses

Vancouver, 2006 © 2004 BRGM Use of Geophysics

Vancouver, 2006 © 2004 BRGM Geophysics as Input Geophysics provides a means of ‘sampling at depth’ –Advanced geophysical processing technologies can locate boundaries from which we can deduce geology –We are already exploiting such data via ‘generic’ import approaches such as ASCII files and image registration –We will expand our ability to directly use such data by reading a wider range of file formats. Geophysics

Vancouver, 2006 © 2004 BRGM Geophysics – Forward Model Having built a realistic model … and with a knowledge of physical property data - we can compute the geophysical response for gravity, magnetics and any tensor component of either … effectively testing the validity of the model …

Vancouver, 2006 © 2004 BRGM Gas Project – Gravity 1VD vs Gdd 1VD of Bouguer Gravity Airborne Gravity Survey Target Area Computed Gdd (Eotvos) 3D GeoModeller Model 0 km 10 Target Area Geophysics –Forward Model

Vancouver, 2006 © 2004 BRGM Geophysics – Inversion The computation of geophysical responses can then taken to the next stage – a geology- constrained joint gravity/magnetic inversion, including any combination of the tensor components of these. Effectively exploring a wide range of possible models that both satisfy geology constraints – and match the observed geophysical signatures.

Vancouver, 2006 © 2004 BRGM Visualisation - Delivery

Vancouver, 2006 © 2004 BRGM Export 2D to ASCII, GIS Scaled 2D presentation quality MapPrint of sections & map Export 3D to T-Surf (wireframe) Export of web-ready VRML for viewing in Windows Exporer browser (with Blaxxun plug-in) Delivery

Vancouver, 2006 © 2004 BRGM Conclusions GeoModeller assists geologists in rapidly building 3D models, visually reviewing them … and revising them … to make better 3D models We have exports for delivering the results to end-user clients We can effectively test the validity of our models with geophysical forward and inverse computation of magnetics, gravity and their tensor components

Vancouver, 2006 © 2004 BRGM Acknowledgements Intrepid Geophysics’ commercialisation of the GeoModeller software has been supported by … The GeoModeller Consortium – Geoscience Australia, the state Geological Surveys of NSW, Vic, SA, WA, NT & Qld, CSIRO, Geological Survey of Namibia, Barrick Gold (formerly Placer Dome) and Geological Survey of Canada Australian Government - International Science Linkages This project is proudly supported by International Science Linkages established under the Australian Government’s innovation statement, Backing Australia's Ability BRGM – On-going development in several research topics by the R&D group within BRGM The development work is a team effort by many … but the significant individual contributions of the following is acknowledged: Patrick Ledru, Antonio Guillen, Gabriel Courrioux, Philippe Calcagno, James Parsons, Ray Seikel and Richard Lane.

Vancouver, 2006 © 2004 BRGM