Tag: Lithology

Modifying your drillhole data: Interval Selections

By Sam Bain

The “Interval Selection” tool in Leapfrog combines most of the abilities of Grouping and Splitting (as discussed in previous blogs) with fewer restrictions. The Grouping and Splitting tools provide workflows for combining or splitting existing lithologies exclusively. The intervals selection is ideal when elements of both the grouping and splitting workflows need to be combined. For example, perhaps assay data indicates some intervals have been incorrectly logged and need to be assigned to a new lithology. If these intervals have been logged as several different lithologies then they need to be split from their old lithologies and then grouped to a single new lithology. The interval selection tool allows you to do this.

Figure 1: Right click the interval table and select the "Interval Selection" option

Figure 1: Right click the interval table and select the “Interval Selection” option

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Modifying your drillhole data: Splitting lithologies

By Sam Bain

The “Split Lithology” tool (available in Leapfrog Geo, Geothermal, and Hydro) creates a new lithology column by sub-dividing lithologies in an imported column. Often simple logging will result in repeating intervals on each drillhole and these will need to be separated for modelling purposes. As an example, perhaps three unique limestone units at different depths are encountered by exploratory drilling. These might all be logged simply as “Limestone”. In this case the splitting tool could be used to divide the “Limestone” intervals into “Upper”, “Middle”, and “Lower” units. Then each unit can be modelled separately. It is important to note that the original logged intervals are preserved, and the new splits are made in a new interval column. The modeller can correct or re-interpret the logging without altering the original field data.

This blog explains how the “Split Lithology” tool works by walking through a simple example.

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Modifying your drillhole data: Grouping

By Sam Bain

A standard workflow in Leapfrog is building a geological model from the interval columns of imported drillholes. This workflow requires the importation of a collar locations file, a survey file with drillhole geometry, and an interval table with the observed lithological contacts. In addition, other down-hole information such as from geophysical logging or drill core assays can be imported as interval tables.

Often there will be problems with the drillhole data. Perhaps the logging in the field was inaccurate and two unique units were incorrectly lumped into one. Of course, the opposite could happen if an eager geo sub-divides a single sandstone deposit into separate poorly sorted and well sorted units. In these situations, the drillhole data needs to be edited so that a new unit is defined or existing units are combined. The “Group Lithologies” and “Split Lithologies” tools in Leapfrog allow you to create a new interval column based on edits of an existing interval column. An additional tool called “Interval Selection” has been developed that uses elements of the grouping and splitting workflows to create a new interval column. In this post we will look at the “Group Lithologies” tool.

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