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Geoscience for GIS
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Andrew Zolnai
Let’s use what we already have at hand
• ArcMap:
• Many datasets at once is the sweet spot
• Simple surface and thickness trends
• Model builder to implement workflows
• Extensions:
• Spatial Analyst (raster integration)
• 3D Analyst (simple surface analysis)
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• 3D Analyst (simple surface analysis)
• Interoperability (link other datasets)
• Output (ArcReader, MapBook, Schematic etc.)
• Web services
• ArcIMS (old but stable and widespread)
• Web services (on-line community)
• ArcGIS and Image servers (new and improved)
• Intent here
• Provide rough sketches with existing tools @ hand
• As first step to further integrate with other systems
ESRI tools vs. Other tools
• Upcoming release with simple grid/contouring in 3D Analyst
• Enhance current extension with simple industry-standard code
• Use the 3D-, Spatial- or Geostatistical-Analyst
• Note current restriction: single ZM per XY (topologic integrity constraint)
• Create multi-patches
• Download a script from ESRI• ArcScripts page
• Download / buy shareware• such as ETgeowizard
• Buy software that extracts, transforms and loads (ETL)
• Safesoft FME Workbench
• Use existing integrator tools such as:
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• Create multi-patches• not easy to implement but resources
do exist
• Use ArcMap Model Builder to integrate other desktop grid/contouring
• note that this is less evident and needs some scripting skills
• Use ArcGIS Server SDK to integrate other server-side grid/contouring
• note that this is not evident and needs programming skills
• Use existing integrator tools such as:• ArcView extensions by CGG, Landmark
or Schlumberger
• Direct data exchange tools such as
• OpenSpirit
• ESRI Data Interoperability extension (a subset of FME Workbench)
• Let ArcMap read web services that post grid/contours
• Such as Petrosys
ESRI tools vs. Grid/contours
• Evenly spaced points
• 2.5D topography, culture
• Use GRID or TIN directly
• Use Spatial Analyst
• Interpolate surface from points
• Contour interpolated surfaces
• IDW (allow barriers)
• Spline (smooth or tension)
• Unevenly scattered points
• 3D Wells, reservoirs
• 2D / 3D seismic surveys
• Use gridding algorithm
• To interpolate even datasets
• Size / direction to reflect geology
• Use contouring algorithm
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• Spline (smooth or tension)
• Krigging (geologic model)
• Display in 3D and Spatial Analyst
• Draping
• Shading to show structures
• Thickness and trend relationships
• Use Model Builder
• Link together several processes
• Use canvas to mimic workflows
• Overlay other datasets
• Culture, permits, parks etc.
• Satellite imagery, and
• Real-time tracking data
• Similar algorithms
• Model the geology
• Display results
• 3rd party application
• Read web services
• Read server services
• Import into GIS
• Use grid or raster
• Think of 3rd party as pre-process
• Think of GIS as post-process
• Link to any tool at left
• GIS is not just for mapmaking
• Maps only report from database
Simple Thickness Workflow
• ArcMap
• Have two horizons as raster files
• Raster Calculator is in Spatial Analyst menu
• Subtract the two surface to get a thickness
• ArcScene
• Drape the thickness on the lower surface
• Contour from 3D Analyst | Surface Analysis
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• Contour from 3D Analyst | Surface Analysis(more complete contouring in next section)
• Drape the contours on formation top(that which is seen on logs or seismic)
• Extrude them down from the top
• Quick area and Volume from thickness
• Mimic porosity effect by using Z value
• Show simple volumes in vector space
• Multi-patches for wellbore representation
DATA: from EarthSoft's EQuIS website
Contouring Workflow
• Three options
• IDW (Inverse Distance Weighted, similar to Natural Neighbours)
• Non-interpretive computation on neighbouring points
• Calculates from fixed raster surrounding sample
• Honours faults as polyline barriers
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• Spline
• Force a curved surface through the raster points
• Regularised: smoothest shape (stratigraphic plays)
• Tension: tune the stiffness (structural plays)
• No barriers but tuning parameters
• Kriging
• Average from a cloud of surrounding points
• Can be made very complex (Geostatistical Analyst)
• Can be shaped to mimic geology
• E.g.: structural trend s.a. fracturing
Display Options
• Viewing the data
• In ArcScene
• Use transparency and priority to show various datasets
• Use the illumination to view trends
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• In ArcMap
• Use the paint tool to compare overlaps
• Use the same tool to verify raster (surfaces) and vector data (faults) coincide
Interpretation
• How is it interpreted?
• If for example thickness increases with elevation (with or without a mirror image if the entire structure is preserved), that may be an indication of thickening via fracturation atop an anticline, and therefore of structural trap and play (below left)
• If however thickness decreases with elevation (below right), that may be an indication of a pinch-out and therefore of a stratigraphic trap and play (usually these also occur alone, and do not have an adjacent mirror image).
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(usually these also occur alone, and do not have an adjacent mirror image).
• The presence of conjugate faults (two fault trends that are at a low angle to each other, below left) is often aligned with a regional fold or bend, and may also indicate a structural play.
Conclusion
• What more can be done?
• More factors can be taken into consideration using more Spatial or 3D Analyst and other extensions
• Model Builder can be used to
• concatenate several repetitive calculations and operations
• thus mimic entire workflows
• briefly described in next section
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• briefly described in next section
• Note
• ArcMap tools are used out-of-the-box to show what can be with GIS tools as-is
• neither scripting nor programming was used here
• This will not replace gridding / contouring or reservoir analysis packages
• GIS is meant to work in conjunction with those packages, as noted in the opening table
Thank you
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http://www.zolnai.ca
Course notes available
Model Builder
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Optional
Model Builder - 1
• A canvas allows to link together tools from ArcToolbox:
• Based on input data and a process
• Output data is next process’s input
• Running the model steps through each process:
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through each process:
Model Builder - 2
• Resulting model:
• Resulting surface:
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Model Builder - 3
• What was done? • Inverted a formation top into a raster slope
• Modelled surface water flow as an analogue to subsurface petroleum flow
• Draped the result onto the original formation top
• Thus approximated up-slope subsurface fluid flow
• What was used?
• Spatial Analyst extension to process rasters
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• Spatial Analyst extension to process rasters
• 3D Analyst extension to display vectors
• Model Builder tool canvas to tie it altogether
• Only with available pop-up and drop-down tools
• Caveats
• This is a surface flow model adapted to subsurface flow
• Flow will diverge not converge, and create many vertices
• To be further refined with additional surface factors
• Such as described in the contouring section above
Resources
• Best Practices: GIS for Petroleum
• ESRI 2007, online PDF
• Visualizing integrated three-dimensional datasets (multipatches)
• Ford, A
• ArcUser (ESRI), January - March 2007
• Introduction to GIS for the Petroleum Industry
• Gaddy, D.E.
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• Gaddy, D.E.
• PennWell, 2003
• Geographic Information Systems in Petroleum Exploration and Development
• Coburn, T.C. and J.M. Yarus
• AAPG, 2000
• Contouring Geologic Surfaces with the Computer
• Jones, T.A., D.E. Hamilton, and C.R. Johnson
• Van Nostrand Reinhold, 1986