Spanish to English Tech/Engineering Engineering (general) Water wells/pipe integrity

Dear colleagues,

I am having difficulty finding a translation for 'resistencia enfocada (FEL)' in the following part of the text regarding pipe integrity related to water wells:

Elaborar un programa de investigación geofísica para la aceptación del pozo, en base al diseño del mismo y el contexto geológico.
El programa debe asegurar la validación de:
Integridad de las conexiones de las tuberías, por ejemplo, registro de resistencia enfocada (FEL)

There is a tendency throughout the text to quote English acronyms, so I suspected FEL would be another one, but I haven't found anything related to this one.

Please provide a reference to back up your answer.