Titanium Stressjoint Design for the Top Connection of a SCR in HPHD

The top connection for the SCRs is one of the main critical points of their design. This situation becomes more challenging principally when there are high pressures and high deep water (HPHD) combined with extreme environmental loads — as is the case in the Gulf of Mexico. PETROBRAS became aware of this problem during the conceptual study of SCRs for ultra-deep waters, where the SWL is in the vicinity of 8200 ft, and with internal pressure of 12100 psi to 15000 psi. With this scenario in mind, a Titanium stressjoint began to be considered as the principal solution to the top connection. Due to this, PETROBRAS — in partnership with RTI ENERGY SYSTEM — developed a study to design a stressjoint model which would validate the SCR. This paper broadly discusses the search for this top connection solution. Dynamic global and local analyses were performed, which led us to the final solution of a titanium and steel mixed stressjoint.