The industry trend of E&P operationsfrom deep water subsea wells is increasing the demand for deepwater drilling rigs. To increase rig availability, operators are resorting to a new strategy of transferring the subsea tree installation responsibility from the offshore drilling rig to a subsea equipment support vessel. The installation from a rig can take 1 to 3 weeks; transferring this responsibility to the support vessel enables the rig to move to the next well sooner and offers significant rig time savings. This paper introduces a fit-for-purpose surface-controlled formation isolation valve (SFIV) designed for the temporary well suspension that is required as a part of this strategy. The valve was developed, tested, and manufactured in accordance with the ISO-28781 standard. A case study demonstrates the operational time savings achieved by suspending a subsea well with the and landing the tree on heave-compensated wire, call the tree-by-wire technique. Temporary well suspension can be achieved by using plugs or mechanical barrier valves. If plugs are used, the rig must return to remove them after the vertical tree installation, which would partially negate the benefits of the new strategy. Therefore, to fully realize the potential of this new strategy, the SFIV was designed to provide a mechanical barrier that could be remotely opened from the support vessel through application of pressure in the hydraulic control lines without loss of actuation capacity. It's a true fail-as-is valve that eliminates the risk of loss of well control in case of a system failure, which has critical importance in well suspension applications. Starting in November 2010, several subsea wells around the world were successfully suspended with the SFIV valves. Besides using the SFIV as a suspension valve, operators can use it to perform production build-up tests, downhole lubricator valve for deployment of long production loggin or pereforating guns. This is possible since the valve could be opened multiple times with high differential pressure across the ball valve without any adverse affects on its sealing capacity.
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.
Objective: The COVID-19 pandemic has presented extraordinary challenges that have tested the resolve of the world and transformed our daily lives. We sought to capture COVID-related attitudes and behaviors of older adults and relate these to views of adolescents from a national study in the USA. Methods: This mixed-methods online survey accepted responses from adult volunteers, age 55+, from April to July 2020 (N = 223). We used a snowball approach to recruitment initiated in the state of Maine (USA). Results: Older respondents tended to report congruent attitudes concerning COVID-19 risks and associated preventative behaviors. Most reported taking Centers for Disease Control and Prevention guidance seriously. In contrast, adolescents surveyed in a prior study reported similar adherence, but less concern. Thematic review of open-ended responses highlights key intergenerational similarities and differences. Discussion: COVID-19 has changed day-to-day life in myriad ways. Attitudes vary within and between age groups. Further research could focus on intergenerational differences in motivations underlying behaviors as well as differing needs for public health education and support.
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