Challenges of Full-Scale Premium Connection Testing in an H2S Environment

Full-scale connection testing in an H2S environment includes key factors that are not assessed in NACE-style coupon testing. A full body connection specimen includes the effects of strain concentrations and surface finish, and exposes a larger specimen area to the corrosive environment so that factors such as material variability, defects, and irregularities can be assessed. In addition, the connection specimen can be submitted to complex loading scenarios with axial tension/compression, internal/external pressure, bending, and heat to simulate multi-axis stress conditions representative of the service environment. Full scale testing in H2S environment however also has its challenges. Safety considerations must be an integral part of the test design.  Equipment reliability is imperative.  As well, H2S testing must be constantly monitored.  This paper describes the challenges faced during this full scale test program including H2S saturation procedures at temperature and pressure, and test fluid sampling to monitor pH without interrupting the test.  In the end, the system including the connection specimen, the steel and the environment successfully completed the 30 day H2S saturated exposure test.