Well Seeker Pro - Compass EDM Erroneous Grid Convergence

Background

An issue has been noted where some Compass EDM export files contain incorrect grid convergence data for a well location. This results in the survey azimuth data for that well being imported into Well Seeker Pro incorrectly.

This document describes the issue and details a solution that appears to allow the Compass EDM file to be exported containing the correct grid convergence data.

Description

In a Compass EDM export file, all azimuths are stored referenced to True North. When importing a Compass EDM file into Well Seeker Pro, where the azimuth data is referenced to Grid North, Well Seeker Pro must use the grid convergence value along with the True North azimuth values to correctly convert and import the azimuths to Grid North. Both the grid convergence and azimuth values in the Compass EDM file must be accurate for the azimuth data to be correctly imported.

In a few cases, when importing a Compass EDM file, the imported azimuth values appear to be referenced to True North, even though the field azimuth north reference is correctly set to Grid North. This issue is caused by the Compass EDM export file incorrectly storing the convergence value in the CD_WELL object as zero, despite it being displayed correctly within the Compass user interface.

Solution

To resolve the issue, the Compass EDM export file has to be recreated with the correct convergence data. To achieve this, Compass users must toggle the Wellhead Location coordinates data between map and geographic in the Well Properties > Location dialog within the Compass user interface. When the Compass EDM export file is subsequently created, the convergence value will be exported correctly.