This document discusses using ESRI ArcGIS tools to perform geoscience analysis and visualization. It provides examples of using ArcMap, extensions like Spatial Analyst and 3D Analyst, and web services to [1] model simple surface and thickness trends, [2] compare ESRI tools to other gridding and contouring tools, and [3] demonstrate workflows for thickness mapping and contouring. The document concludes that ArcGIS tools can provide initial analysis and integration with other datasets but are not a replacement for specialized reservoir modeling packages.

1. Geoscience for GIS
Andrew Zolnai
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2. 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)
• 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
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3. ESRI tools vs. Other tools
• Upcoming release with simple • Download a script from ESRI
grid/contouring in 3D Analyst • ArcScripts page
• Enhance current extension with • Download / buy shareware
simple industry-standard code
• such as ETgeowizard
• Use the 3D-, Spatial- or
Geostatistical-Analyst • Buy software that extracts,
transforms and loads (ETL)
• Note current restriction: single ZM
per XY (topologic integrity constraint) • Safesoft FME Workbench
• Create multi-patches • Use existing integrator tools such as:
• not easy to implement but resources • ArcView extensions by CGG, Landmark
do exist or Schlumberger
• Use ArcMap Model Builder to • Direct data exchange tools such as
integrate other desktop • OpenSpirit
grid/contouring
• ESRI Data Interoperability
• note that this is less evident and extension
needs some scripting skills (a subset of FME Workbench)
• Use ArcGIS Server SDK to integrate • Let ArcMap read web services that post
other server-side grid/contouring grid/contours
• note that this is not evident and • Such as Petrosys
needs programming skills
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4. ESRI tools vs. Grid/contours
• Evenly spaced points • Unevenly scattered points
• 2.5D topography, culture • 3D Wells, reservoirs
• Use GRID or TIN directly • 2D / 3D seismic surveys
• Use Spatial Analyst • Use gridding algorithm
• Interpolate surface from points • To interpolate even datasets
• Contour interpolated surfaces • Size / direction to reflect geology
• IDW (allow barriers) • Use contouring algorithm
• Spline (smooth or tension) • Similar algorithms
• Krigging (geologic model) • Model the geology
• Display in 3D and Spatial Analyst • Display results
• Draping • 3rd party application
• Shading to show structures • Read web services
• Thickness and trend relationships • Read server services
• Use Model Builder • Import into GIS
• Link together several processes • Use grid or raster
• Use canvas to mimic workflows • Think of 3rd party as pre-process
• Overlay other datasets • Think of GIS as post-process
• Culture, permits, parks etc. • Link to any tool at left
• Satellite imagery, and • GIS is not just for mapmaking
• Real-time tracking data 4 • Maps only report from database

5. 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
(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
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6. 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
• 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
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7. Display Options
• Viewing the data
• In ArcScene
• Use transparency and priority
to show various datasets
• Use the illumination to view
trends
• In ArcMap
• Use the paint tool to compare
overlaps
• Use the same tool to verify
raster (surfaces) and vector
data (faults) coincide
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8. 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).
• 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.
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9. 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
• 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
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10. Thank you
http://www.zolnai.ca
Course notes available
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11. Model Builder
Optional
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12. 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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13. Model Builder - 2
• Resulting model:
• Resulting surface:
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14. 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
• 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
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15. 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.
• 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
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