GEOG 4891 Lecture Notes - Lecture 6: Casing String, Borehole, Wellhead
Document Summary
Casings are set into the well mainly for: avoiding interaction between formation and wellbore pressures, preventing wellbore caving & collapse. Facilitating installation of wellbore and wellhead equipment for production. Establishing confine production: providing means for pressure control, preventing underground fresh water contamination, reducing water-cut and sand in hc production. Casing designer (drilling engineer) mainly determines: number of and lengths of casing strings (on the basis of pressure profiles of concerned well, casing sizing (on the basis of final casing string size, casing weights and grades. Safety factors (on the basis of tension, collapse and burst which are interacted) Starting size of the well determines casing design. The total length of casings with uniform outside diameter and run into the well in a single operation is called casing string. Each casing strings has its upper end at the surface except liners.
