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