Abstract: Seal design method of premium threaded casing connections is studied with finite element analysis and full-scale test. The criterions of seal design are presented that can keep the joint leak-tight as well as not damaging the seal surface. Furthermore, several new premium connections that designed according to this method were manufactured with numerical control machine tool. The full-scale test of these connections show that their seal property is very well. This indicated that the seal design method given is effective.

Key words: Casing connection, Finite element method, Full-scale test, Premium thread, Seal property