When the casing configuration (casing size and setting depth) has been selected, the loads to which each string will be exposed will be computed. Casing, of the required size, and with adequate load bearing capacity will then be selected from manufacturer’s catalogues or cementing company handbooks.
Casing joints are manufactured in a wide variety of sizes, weights and material grades and a number of different types of connection are available. The detailed specification of the sizes, weights and grades of casing which are most commonly used has been standardised by the American Petroleum Institute – API. The majority of sizes, weights and grades of casing which are available can be found in manufacturer’s catalogues and cementing company handbooks (e.g. Halliburton Cementing Tables).
Casing is generally classified, in manufacturer’s catalogues and handbooks, in terms of its size (O.D.), weight, grade and connection type: