Performing statistical analysis

The Statistical Analysis tool allows you to create histograms, scatter plots, and variograms for any property attached to various data representations in your project (2D grid, 3D grid, well, tri-mesh, 3D mesh, polyline set, well marker, point set, or a combination of these). You can use advanced filtering options to analyze the selected property data in more detail, per grid zone for example.

To create statistics

  1. Open the Statistical Analysis tool.
  2. In the drop-down list select the type of object on which you want to carry out the analysis.

  3. In the second drop-down list select the model containing the objects you want to analyze. The list-box view will populate with the objects that match your selected object type and model.

    You cannot select multiple grids. You can select multiple objects of all other types.

  4. In the list, select the object(s) that you want to include in the analysis. If you select more than one object, the combined properties of the objects are considered as one population for the statistical analysis.

  5. Select the property of the selected object(s) that you want to analyze.

    Limit well input to upscaled logs  If the selected object type is Wells, this option filters the selection list to show upscaled well logs only.

  6. Set filter - Here you can specify three filter options:

    • Zone / Layer / Region filter
    • Facies / Lithology filter
    • Custom filter

    Use of a filter is optional. Filters can be used to generate statistical data for a specific region of your model. When you select a filter, you are able to specify a discrete property which you want to use for filtering.

    Important   If you select multiple filter options, the logical AND operation will be applied; statistics will only be generated when all filters are intersecting.

    Connect wells to 3D Grid geometry  If you selected Wells as the object type in Step 1 of the form, you can select different objects you want to use for filtering. For example, you can select all wells in Step 1, a well property in Step 2, and a JewelGrid as object filter, allowing you to analyze the selected well property ONLY in a selected JewelGrid region.

    The object selector is only available for analyzing Well objects; in all other cases this selector is disabled.

    Zone / Layer / Region filter  Check this to use a discrete property, or property template Zone, Layer or Region, for filtering.

    Facies / Lithology filter  Check this to use a discrete property or property template Facies or Lithology, for filtering.

    Custom filter  Check this to use a discrete property that does not correspond with the previous two options.

    The following options are available for each of the three filtering selections:

    Filter property drop down box  Select the discrete property to filter on, for example, a zone property in case you want to analyze property data per zone.

    Classes  Select one or more discrete property classes to filter on, for example Zone1 and Zone2 in case you want to analyze property data only for Zone1 and Zone2.

    Separate output for each selected item  Check this option if you want to generate statistics for each class individually. Uncheck the option in case you want to generate statistics for the selected classes together.

  7. The 'Create statistics' step allows you to create three different types of statistical charts: Histograms, Scatter plots, and Variograms. Check the chart type you would like to generate, which will open a panel with chart controls that you can specify.

    Histogram  Select this option if you want to generate a histogram chart. The following additional chart options are available and are only needed to generate the initial Histogram view.

    Number of bins  Specify the initial number of histogram classes / bars you want to create. In case of analyzing a discrete property, this option is disabled because the number of bars is fixed by the number of discrete classes.

    Weighted or Number of samples  Allows weighting the grid or well property values in the generated histogram based on cell volume (Weighted option checked). If you don’t want to apply weighting, check the Number of samples option.

    Add to existing view  Check this if you want to add a new property of the same type (selected in panel Steps 1 to 3) to the active Histogram view. You can use it, for example, to analyze well log data and resulting grid property data in one histogram chart.

    Scatter plot  Select this option if you want to generate a scatter plot chart. The following additional scatter plot options are available and are only needed to generate the initial Scatter plot view.

    Vertical axis  Select the property to be displayed on the Y-axis in the scatter plot against the property selected in the form.

    Symbol color  The property to be used for color coding the points in the scatter plot. It is optional; select None in case no color property is needed.

    Variogram  Select this option if you want to generate a Variogram chart. The following additional chart options are available and are only needed to generate the initial Variogram view.

    Lag distance  These controls allow you to set initial variogram search radius in both lateral and vertical directions.

    Lag size  These controls allow you to specify initial lag distance (step of the search radius increment) in both lateral and vertical directions.

    # Lags  These values show you the calculated number of lags in both lateral and vertical directions. These controls are read-only and are calculated as Lag distance divided by Lag size.

    Lag tolerance  This control specifies the tolerance used for each lag. Lag tolerance is quoted as a part of the lag distance. Hereby, a value of 0.5 (or 50%) means that all points between neighboring lags will be taken into account during variogram calculation, a value less than 0.5 means that some data may not be considered. This parameter cannot be greater than 0.5 to prevent double counting of points.

    Total calculation   Select this option if you want to use all pairs available in the selected property. This option gives the most accurate variogram, but can result in a time consuming calculation when you create a variogram of a grid property.

    Partial calculation   Select this option if you want to use a part of the possible pairs of the selected object and property to speed up the variogram calculation, e.g. when you want to model a grid property. You need to specify an "Average number of pairs per lag", which is the average you believe are needed for a valid variogram chart. In this case of calculation, random pairs from property are added to the variogram results to achieve the average number of pairs in each lag. Partial calculation is the default option to speed up the initial calculation process.

    Normalize data for input to simulation  This option will transform the selected property data into a normal score, which mean a normal distribution with a mean value of 0 and a standard deviation of 1.

Click the Create button to generate the selected charts. The selected chart will be created as a new view. Each of these will show the chart and also provide more detailed control to further specify and analyze the chart.