Thermal Mitigation Design for Appomattox Flowlines

Abstract

Novel methods were required to address the high operating temperatures of the Appomattox flowlines. Appomattox is predicted to operate as high as 365F, requiring thermal mitigation along the length of the flowline and anchoring at the base of the riser. Existing thermal mitigation methods were screened but were found unacceptable. Alternatively, a system of multiple buoyancy modules was found to be highly efficient and reliable to address the thermal expansion along the length of the flowline. Also, a unique rigid anchoring system was designed to restrain the riser base. Appomattox began production in Q2 of 2019. A flowline survey performed in Q3 2019 demonstrated good alignment with the analysis predictions for buckling locations, shapes and buckle magnitudes.