Advancements in Structural Well Integrity Design and Operation

Abstract

Abstract With the heightened focus on safety in drilling operations, Det Norske Veritas(DNV) AS together with the drilling industry has started development of aseries of Recommended Practices (RP) for structural design and operation ofdrilling and well systems. The motivation for developing the industryguidelines stems from the fact that existing international standards providelimited or no guidance on overall system design and structural integrity. Theaim in creating the new RP series is to provide a sound framework for theentire drilling and well system in a systematic manner. The new RP seriestackles issues such as system engineering and interface design as well asproviding detail guidance on strength and fatigue calculation and informationand integrity management. It is seen as crucial that the drilling industry incorporates and adheres to asystematic and consistent method for safe design and operation of itsequipment. The RP development is part of an ongoing joint industry project (JIP)facilitated by DNV with participation from BG Group, BP, Chevron, Det Norske, Eni, ExxonMobil, GDF Suez, Lundin, Marathon, Nexen, Shell, Statoil, Talisman, Total and Woodside. The core of the RP series provides an overall design andoperational philosophy of drilling and well systems, and as there typically aremany individual components in a drilling and well system, the RP seriesprovides guidelines with regard to interface interactions and control ofresponsibility throughout a well's entire lifetime. The RP series combines thestrengths of the already existing design methodologies available in theindustry today, and provides specific guidance on structural strength andfatigue design. As such it represents a significant improvement derived fromkey elements of the best practices from around the world. The RP series consists of 4 separate volumes. Volume 1 provides an overalldesign philosophy for drilling and well equipment; Volume 2 covers strengthcapacity design, i.e. ULS/ALS. Volume 3 covers fatigue design, i.e. FLS andVolume 4 addresses integrity and information management. Introduction Ensuring structural integrity of drilling and well systems has been importantin the offshore industry ever since the first offshore wells were drilled inthe Gulf of Mexico. With current technology and its challenges where manyconductor and wellhead systems are located on the seabed and connected to anoffshore drilling unit, structural integrity has become a focus area for thedrilling industry. Even with current international codes and standardsavailable, a systematic method for ensuring structural integrity of the wellsystem has yet to be fully implemented. Ensuring structural well integrity isdefined in the JIP project as taking into account all of the loads acting onthe well system during its lifetime, i.e. drilling, completion, production, workover/intervention and plug and abandonment.