Formation Integrity Test (FIT)

Formation Strength Test

A Formation Integrity Test (FIT) is a procedure used in drilling operations to assess the strength of the formation at the casing shoe. It ensures that the formation can withstand the pressure exerted by the drilling mud and any additional pressure from well control operations without fracturing.

An FIT is performed in the same manner as a LOT however the major difference is that the pressure is not increased until a fracture occurs and only to a predetermined pressure which has been calculated as sufficient to withstand wellbore conditions.

In areas where the formation strength is generally well understood, an FIT is preferred as it reduces the risk of fracturing and weaking the formation and puts less stress on the well.