Well casing is subjected to a wide variety of loading mechanisms that can cause temporary or permanent deformations. These deformations can be due to geological processes or well operations. They can impair or prevent access to the full depth of the well or compromise the pressure integrity. They can occur instantaneously or progress over many years.
Many historical well workover reports have reported casing deformations as “casing collapse” when a tool string cannot pass by a “tight” interval. In fact, collapse is not a common deformation mode, with shear and buckling deformations being much more likely modes of well failure.