Example Flow: Making Isopach Grids
This article covers how to use a Flow to make isopach grids using your formation tops, well headers, and deviations (optional). using Danomics constrained gridding tools that enforce geological consistency.
Note: if you are using deviation surveys, you must have already processed them as shown in this article.
The following tools are used in this order:
- PointsInput >> Used to select your formation tops database
- PointsSelect (optional) >> Used to filter down to the selected tops
- TopsToTVD >> Convert tops to TVD space using deviation surveys (if available)
- TopsToStructureGrid >> Constrained gridding process
- GridOutput >> Writes the grids to a .grid file
The PointsInput serves the purpose here of bringing formation tops into the Flow. This tool is flexible and can accept several different data types, such as headers, tops, and points.
The PointsSelect is optional - here we are using it to select a subset of our formations. This is useful when you are only interested in the major formations and not every subzonation. See the example here:
The TopsToTVD tool brings in the well headers and the deviation points and allows the formation top to be put in XYZ space. Note, this must be a processed deviations points file.
TopsToStructureGrid performs the gridding, even for isopachs. You can adjust the cell count or cell size, select the gridding method, and add options for what happens with respect to pinchouts on a zone-by-zone basis. E.g., does a formation pinchout upwards against the overlying formation or downwards against the underlying formation.
Crucially, you will set the Outpu property to "Resolved isopach".
Finally, we end the Flow with a GridOutput that writes the grids to a file.
Tips and Tricks
- All of the output is in Danomics multi-grid format. This means that it will create a grid for every formation in one go.
- Remember that your deviation surveys must be processed ahead of time!
- TopsToTVD must be applied even if you are not using deviations.
- The Resolved isopach is the isopach after corrections for pinchouts and tops reconciliation. This is consistent with what occurs in the example structure gridding flow.
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Sample data to get started
Need some sample data to get started? The files below are from data made public by the Wyoming Oil and Gas Commission. These will allow you to get started with petrophysics, mapping, and decline curve analysis. Well header data Formation tops data Deviation survey data Well log data (las files) Production data (csv) or (excel) Wyoming counties shapefile and projection Wyoming townships shapefile and projection Haven’t found the help guide that you are looking for?