Case Study: Deepwater Design Verification and Validation Testing for Subsurface Safety Valves for HPHT Environments

Abstract

The evolution of subsurface safety valve design for HPHT application has created the need for advanced design verification and validation testing to ensure "fit-for-service" application in a HPHT environment. With the release of API 14A 12th edition and the new V-1H validation grade, couple with Annex H for verification and validation requirements for high-pressure, high temperature environment, strenuous validation testing is required. Navigating the requirements can be difficult with the divergence from API 14A 11th Edition, Class 1, 2, 3, & 4 classes of service, to API 14A 12th Edition, V4-1 to V1-H. In addition to the validation grades, specialized Annexes (D, G, H, J, and L) requires collaboration between the Operator, with its functional specifications, and the service company to develop a specific design verification and validation testing program for Subsurface Safety Valves suitable for HPHT application. This paper specifies a "fit-for-service" verification and validation plan conducted collaboratively by an Operator and Supplier. The validation testing plan outlines the requirement for V1-H validation grade along with required API 14A Annex testing. The paper also includes details on metallic component analysis using finite element analysis (FEA) and current ASME BPVC Section VIII using true-stress true-strain curves for accurate verification of the equipment design. Localized stress discontinuities and plastic localized yielding design criteria were also used to determine adequate protection against these failure modes, or if additional analysis is required. With increasing regulatory oversight in HPHT technology development, product qualification planning requires in-depth knowledge of the designs and the criticality of the Subsurface Safety Valve as a critical barrier component. The Supplier and an Operator would like to share their experience and lessons-learned with the industry that would enable industry engineers to understand the requirements of design verification and validation testing of Subsurface Safety Valves for "fit-for-service" in a HPHT environment.