Partner St.Gallen has been aiming at supporting the work of S4CE partners by indirectly determining well integrity by simple means (existing methodology / technology) within the easy accessible sections of the well during standard well maintenance procedures. The work was carried out at St.Gallen field site and well in September 2020.  The actions and results are described in detail in a report delivered by St. Gallen “Well integrity measurement at St.Gallen field site by temperature profiling within cased well bore sections“ and the related data will be published on S4CE data hub IS-EPOS within Episode St.Gallen in February 2021.

It has been shown that even with this low-budget solution certain questions regarding well integrity (well integrity issues by means of damaged borehole casings) can be evaluated and answered. It was concluded that the method used was a fast and easy way to indirectly assess well integrity issues for this kind of sealed, non-pressured, non-operational well. Additionally, the results could be used as reference / for validation purposes by S4CE partners.

A first ever undisturbed temperature profile to about 3.5 km total vertical depth was obtained within “St.Gallen GT-1” well and a geothermal gradient was determined which – besides other data – led to a better understanding of this (subsurface) location and could lead the way for more geothermal development in the region of North-east Switzerland / St.Gallen. The method used could be adapted for wells worldwide with similar status to assess environmental issues in relation to well casings.