How do casings fail, EXPERT? When a well is completed, the casing lines the entire bore, from the shoe to the surface. In most of the bore, there is at least two layers of casing, cemented together. Only in the pay zone is there a single layer of casing cemented to the bore.
Now, when the well is fractured, the first process is perforation or making intentional holes in the casing that extend past the cement and into the formation. A perf gun holds a number of shaped charges which are initiated from the surface. Then packers are installed to isolate this perfed zone, only then is fracturing possible.
Most wells are fractured in multiple zones, independently done by installation of packers at various depths. At no time is the entire casing subjected to fracturing pressure, there is no way to accurately fracture a well in one step due to anisotropic nature of formations. Plus deeper formations of similar conductivity will have greater pore pressure just from hydrostatic column.
Now, who are the experts here and who is the drip under pressure?