Locating Abandoned Wells
December 9, 2019
Abandoned wells need to be located and decommissioned. There are several steps required in order to accomplish this. The first step is to search for drill logs filed with the City/Region or MOE. Some historic inspection files can also have photographs taken at the site to aid with referencing the well to surface structures and features.
The next step is to view historic air photos. The following historic Air photo displays a likely historic well cover that has since been buried.
The next step is to locate nearby reference features and setup a geophysics survey grid. Typically a Geonics EM31 survey is carried out on lines spaced 2 metres apart. If the terrain allows, this is followed up by EM61 metal detection and GPR (ground penetrating radar) at 500 MHz and/or 250 MHz. Some abandoned wells are dug-wells requiring a different approach compared to searching for drilled wells.
If the suspected well is associated with a building, the basement can be viewed for suspect piping. A Radiodetection transmitter can be connected to the suspect pipe and possibly traced back to the abandoned well using the receiver.
In some cases, just the act of carrying out the EM31 survey is sufficient to locate suspect features such as piping extending from the abandoned well, as indicated in the first photo.