The usage of monolithic isolating devices in cathodically protected systems is considered by NACE SP0286-2007. Unfortunately the use of these accessories has been difficult to carry out in discharge lines of wells with high pressure and temperature and sour service conditions, mainly because the materials of the seal and dielectric isolation systems can suffer damages associated with the stress generated by the operating pressure and stresses generated by the displacement produced by the temperature. Under these operative conditions combined with sour service hydrocarbons and saltwater presence the non metallic materials also can suffer quick degradation, resulting in leakage of hydrocarbons, affecting the environment, the security and the production. In the present work the performance of non metallic materials with different sealing and isolation systems that presented failure was analyzed.
Mechanical characterization and identification by infrared spectroscopy of the different non-metallic elements was carried out. Using the results of mechanical characterization of the non-metallic elements and on the basis of results of flexibility analysis, conducted previously in a sour service, high pressure and temperature discharge line, the performance of an “U” shape main seal system was simulated via FEM. The simulated mechanical performance of the isolating joint was related to results obtained previously in failure analysis of component failed under the same operative conditions. As result from this study an integral methodology for the design, selection and procurement of monolithic insulating joints applicable to high pressure and temperature sour service discharge lines was generated.