Failures Related to API 5CT High Strength Steels

American Petroleum Institute (API) 5CT high strength steels are extensively used for casing strings in  wells subjected to high cyclic hydraulic fracturing loads. While non-sour grades of API steel such as P110 casing strings have been used satisfactorily for well construction, standard API P110 connections have seen higher rates of failures than pipe body failures in shale wells that require hydraulic fracturing. P110 pipe body and connection failures have also been experienced in cases where poor manufacturing practices have been employed to produce P110 steel casings and connections  used in wells subjected to these high hydraulic fracturing loads.