Cost-Effective Upgrades of Drilling Risers to 20,000 Psi Applications through Composite-Reinforced Steel Choke and Kill Lines

Oil and Gas companies are considering drilling operations in the challenging high-pressure/high-temperature (HP/HT) environment, which requires new equipment to be qualified to 20,000 psi working pressure and 350°F maximum temperature. In this study, IFP Energies Nouvelles (IFPEN) has considered the use of composite-reinforced steel Choke and Kill (C&K) lines for retrofitting an existing drilling riser equipped with 15,000 psi steel C&K lines to HP/HT applications. The feasibility of this upgrade solution has been validated through composite material testing and design studies. The composite provides a 20,000 psi Choke and Kill line that is lighter than a 15,000 psi steel line for (almost) the same outer diameter (OD) while maintaining a nominal inner diameter (ID) of 4.5" for safer operations and ensuring a large safety margin on burst. These major advantages allow the C&K lines to be replaced without increasing the riser mass and with no other modification on the riser design. In particular, the expensive buoyancy modules can be kept in place. Through combining the best features of steel and composite, this technology offers a cost-effective way to upgrade an existing drilling riser to 20,000 psi/350°F applications.