Working with Depth Plots

Overview

With a well depth reference system and integrated stratigraphic tops from the well artefact the depth plot provides a natural tool to explore the within well variation in geochemistry.

Version: 2.0+ (Sept 2021)

Usage: Graph --> New graph --> New depth plot...

How to use in practice

Depth Plots

Creating a new depth plot is straightforward. This page focuses on how to display geochemical data relative to well artefact stratigraphic tops and against differing well depth schemes (MD vs TVD) & datum's.

Interaction between the geochemical data and the depth plot features uses the Graph Manager.

Stratigraphy

It is very important that you apply a well to the graph (so that the depth plot knows which tops to show), even if you only have a single well in the project. Applying the well (drag and drop the well on the artefact) is critical to showing the stratigraphy.

From the graph manager Layout tab you select to show or hide the Lithostratigraphy Layer and Chronostratigraphy Layer as a respective whole. By default both tops are show, the Lithostrat tops being shown is blue on the plot and the Chronstrat tops in black.

Selecting the Lithostratigraphy Layer and Chronostratigraphy Layer entries brings up a view below the Layout elements that allow the user to select which stratigraphic unit level(s) to show on the depth plot. Within this view you are presented with the option to show the primary or alternative tops.

As explained on graph manager the user is able to select what level of data to display on the litho- and chrono-strat data.

Where multiple levels exist at the same depth the most general information will be shown by default. In the example image shown here we will show lithostratigraphy at both Group and Formation level. Where a formation top is at the same depth as the corresponding Group into which that formation falls, the group top will be shown on the plot.

The options available for selecting what information to display for the stratigraphy makes this feature very flexible and powerful. Note these tops are also used to assign sample level stratigraphy and are themselves fully depth referenced, so will be plotted correctly relative to any datum selected.

If the well artefact is removed from the depth plot, all data in the project (or the applied sample set) is shown on the plot, but no tops can be shown.

Depth Datum

To control the datum against which the data is plotted use the graph manager Axes tab. Select the Depth axis in the top Axes list to display the available depth options. From here you can choose to display the geochemical data with respect to measured depth (MD) or true vertical depth (TVD) or opt to display to a different Depth datum. You can define the label used for the depth axis.

Exploration in depth plots

The pan / zoom interaction within depth plots, the selection through brushing / rectangle selection is similar to other plots, and is accessed through the Exploration tab on graph manager.