Troubleshooting Anti-Collision

Troubleshooting differences in anti-collision results between Well Seeker and other well planning software


Users can sometimes find that Well Seeker produces different anti-collision results, when compared to other well planning software. To analyse this discrepancy, the user must ensure that both programs have exactly the same setup and inputs, so that they can be sure they are comparing like-for-like results.

This document details the procedures that the user should follow to double check that the setup and inputs they are using to generate the anti-collision results in Well Seeker match those of the program they are comparing against.


The steps below should be repeated for the reference well/plan and any offset wells/plans that exhibit a difference in anti-collision results between the software packages.

1) Centre-to-Centre Measurements

Before comparing ellipse of uncertainty or separation factor results, it is important to compare the centre-to-centre distance results between the two programs. If these are different, they will create a discrepancy in the anti-collision results even if the ellipse of uncertainty calculations are identical.

If there is a difference in the centre-to-centre results it indicates that the wellbores are not exactly the same in both programs. Double check the following for your reference well and each of the relevant offsets:

a) Survey / Well Plan bottom line

A good initial check is to look at the bottom line of the relevant plan and surveys, and check if these match what you have in the other program.

Discrepancies in the TVD, local (NS / EW) coordinates and the DLS can indicate that there may be some level of inconsistency with the survey / plan points between the programs. Differences in the grid north and east values or the latitude and longitude values may in addition, point to an issue with the surface location.

b) Surface Location

The surface location of the well is defined in the Well Properties window in the Wellhead Location section. It can be defined as an absolute location using grid northing/easting or latitude/longitude, or it can be defined as a distance (north/east) offset from the facility.

c) Survey Program

The survey program is defined in the Actual Wellbore/Plan Properties window. Ensure that the survey program in Well Seeker matches exactly with what is being used in the program you are comparing against.

d) Survey Tie-on Points

As well as the survey program, check that the tie-on points for all surveys is correct and matches with the tie-on points in the other program. The tie-on point for each survey is defined in the Survey Properties window.

e) Surveys / Plans

Finally, ensure that the reference wellbore and offset wellbores have been constructed using exactly the same surveys / planning points. If the survey / planned points are different, or if the number of surveys is different, this will affect both the well path itself and the calculation of the error ellipses.

If you have confirmed that you are getting the same centre-to-centre distance values, but the rest of the anti-collision outputs are not matching, then you now need to compare the inputs that affect the error ellipse calculations.

2) Anti-Collision Settings

The first thing you should compare is the anti-collision calculation settings. In Well Seeker, most anti-collision settings are defined in the Operator Properties window.

There are additional anti-collision settings that can be accessed from the Tools menu (Tools – Anti-Collision Settings)

3) Facility / Well Location Uncertainty

The Facility and Well Properties dialog’s both contain location uncertainty inputs which have an effect on the size of the ellipse of uncertainty calculation and therefore the anti-collision. Check that the values entered here match what is being used in the other program.

4) Magnetics Data

Check that you are using the same magnetics data in both programs. Open the Actual Wellbore/Plan Properties window for your actual well/plan. In the Magnetics section, the Declination, Dip and Total Field values must match exactly with the values entered in the other program. If you have multiple rows in the Magnetics section, the one marked as Active is the one being used in the error ellipse calculation.

5) Survey Tool Error Models (IPMs)

In the Actual Wellbore/Plan Properties window, check that your actual well/plan is using the same survey tool error models in both Well Seeker and the other program. These error models are also known as IPMs (Instrument Performance Models). To check your IPMs in Well Seeker, check the IPM column in the survey program section of the Actual Wellbore/Plan Properties window.

You can change your IPMs for a well plan in the Plan Properties window, but for actual wells you need to change the IPMs for each survey individually via the Survey Properties window.

6) Error Model (IPM) Terms

If both programs are using the same IPMs i.e. they have the same name, check that the error terms contained in each IPM match. It is possible for two IPMs to have the same name, but contain different error terms. To view the IPMs in Well Seeker, open the Tools menu and select Survey Tool Editor. For each IPM used, check that it matches exactly with the error model used in the other program. This is often the reason for the differences being seen.

Note that the .ipm files used in Well Seeker are compatible with Landmarks Compass. If a Compass edm file was used to import any of the well data into Well Seeker, then the user has the option to also import the ipm files (File – Compass EDM Import Options – Compass Import Settings), ensuring that these match between programs.

The following document details some additional points the user should be aware of: Compass IPM Issues

You can quickly locate the physical .ipm files by clicking on the Open IPM Folder icon in the toolbar of the Survey Tool Editor.

7) BGGM Error Estimates

The BGGM Error Estimate integration is a feature that was added to Well Seeker in version

Available via the survey tool editor, when turned on, this integration allows for real time updates to some of the values in the selected magnetic survey tools Instrument Performance Models (IPM’s). Depending on the selected IPM models, this option will have a direct influence on the error ellipse output and in turn the anti-collision results. Check if this is switched on and if so try turning it off.

8) Compass Diagnostic File

If the program you are comparing the anti-collision results against is Compass, and you have confirmed that the two programs are matching in the above steps, but the anti-collision results are still not tying in, then the next step is to supply Innova with a Compass Diagnostic file. This file contains all the information required to investigate the issue. To generate a compass diagnostic file, follow the below instructions:

When in Compass, open the Survey tools box and check the “Diagnostics” box

1. Open the relevant well, and then run an error ellipse report

a. Don’t worry about the report, you can just close it once it has been generated.

2. Make sure that your computer is set up to show hidden files

a. If you don’t know how to do this, it differs between operating systems, so best to google the required steps.

3. Go to the C drive and search for .txt files. This will take a while. Once the search is over, list the results with the newest at the top. The top file, should be the file you require and you can see the location based on the search.

4. The generated file will be named se1.txt

a. Every time you create a new file, the number will increase by one.

5. Once you have located this file, send it to, along with the following:

a. A Well Seeker debugging file

i. Help – Send Debugging Email

b. A zipped copy of your IPM folder

i. Help – Open Setup File Folder

c. A copy of the Anticollision Report from the other software that you are comparing outputs against

d. A copy of the Survey/Planning Report from the other software that you are comparing outputs against

e. An detailed explanation of the issue you are having ideally including comparative screen shots.

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