Material Issues in Ageing and Life Extension

2011 ◽  
Author(s):  
Erik Ho¨rnlund ◽  
Gerhard Ersdal ◽  
Rolf H. Hinderaker ◽  
Roy Johnsen ◽  
John Sharp
Keyword(s):  
North Sea ◽  
Research Work ◽  
Life Extension ◽  
Material Degradation ◽  
The North ◽  
Design Life ◽  
The North Sea ◽  
Extension Process

A considerable number of the structures in the Norwegian part of the North Sea have passed or are close to their design life. Material degradation will play an important role in the ageing of these structures and the evaluation of their safety. An overview of research work initiated by the Petroleum Safety Authority (PSA) is presented. The paper focuses on various material aspects of ageing related to offshore facilities, the risks they represent to the integrity of a facility and how to deal with them in a life extension process. The paper presents and discusses expectations towards the industry with respect to evaluation of ageing materials in life extension.

Environmental Assisted Cracking of High Strength Subsea Material due to CP

2019 ◽  
Author(s):  
Agnes Marie Horn ◽  
Erling Østby ◽  
Viggo Røneid ◽  
Finn Kirkemo
Keyword(s):  
Fatigue Life ◽  
North Sea ◽  
Fatigue Testing ◽  
Research Work ◽  
Design Guidelines ◽  
Life Extension ◽  
External Loading ◽  
Test Program ◽  
The North ◽  
The North Sea

Abstract Several of the offshore fields in the North Sea are approaching the end of their design life and a cost-effective solution to maximize production is to document that life extension is feasible for an asset. A trend the resent years [1] is that the BOP become larger, hence the required fatigue life increases. One way to meet the increased fatigue life and external loading is to use higher strength steel to meet the design requirements set by the operators. This has motivated research related to the fatigue performance of the base material connector material both for air and under sea water with cathodic protection (CP) [2,3,4] and possible degradation of ductility and toughness in seawater with CP. However, relevant test data for wellheads material that have been in service is not to the authors knowledge, available, nor recommendations in design guidelines related to possible material degradation to be safely applied for life extension of these assets. To better evaluate life extension of subsea wellheads, a test campaign was initiated by Equinor on a retrieved wellhead in 2015. The wellhead had been in operation since 2000 in the North Sea. The general purpose of the test program was to evaluate if the low alloy steel AISI 8630 modified material had been substantial degraded during 15 years in service compared to design material properties and the materials susceptibility to hydrogen embrittlement. The test program performed consisted of slow strain rate testing (SSRT) to document possible reduction of strength and ductility, CTOD testing to document possible reduction in toughness and S-N testing to establish the fatigue strength reduction due to seawater with CP. The outline of the paper is as follows: first a summary of the latest research and trends within wellhead fatigue and materials are discussed. Next, a detailed description of the test program is given: SSRT, toughness testing and fatigue testing are presented. Finally, recommendations and proposal for further research work are given.

A Framework for the Management of Ageing of Safety Critical Elements Offshore

2011 ◽  
Author(s):  
John V. Sharp ◽  
Edmund G. Terry ◽  
John Wintle
Keyword(s):  
Life Extension ◽  
Original Design ◽  
Safety Critical ◽  
Critical Elements ◽  
The North ◽  
Design Life ◽  
Offshore Installations ◽  
Management Processes ◽  
The North Sea ◽  
And Performance

Many offshore installations in the North Sea have now exceeded their original design life and are in a life extension phase. A Framework of six processes has been developed for the management of ageing of Safety Critical Elements (SCEs) in offshore installations. The processes include an analysis of the effect of ageing modes on SCE performance. Examples of performance indicators for typical SCEs are proposed based on how their condition and performance as may be affected by physical deterioration and other effects of ageing. Indicators for calibrating the maturity and effectiveness of the management processes are also suggested.

Ageing of Materials

2008 ◽  
Author(s):  
Erik Ho¨rnlund ◽  
O̸ystein Sævik ◽  
Rolf H. Hinderaker ◽  
Gerhard Ersdal
Keyword(s):  
North Sea ◽  
Life Extension ◽  
Research Projects ◽  
Considerable Part ◽  
The North ◽  
The North Sea ◽  
Degradation Of Materials

A considerable part of the structures in the Norwegian part of the North Sea have passed or are close to their design lifetime. Degradation of materials will play an important role in the ageing of these structures and the evaluation of their safety. Hence, Petroleum Safety Authority Norway has initiated several research projects to investigate into the ageing of materials, and how to ensure robust materials also for life extension. The present paper gives a summary of these research projects.

Life Extension Issues for Ageing Offshore Installations

2008 ◽  
Author(s):  
A. Stacey ◽  
M. Birkinshaw ◽  
J. V. Sharp
Keyword(s):  
Structural Integrity ◽  
Life Extension ◽  
Original Design ◽  
The North ◽  
Design Life ◽  
Offshore Installations ◽  
Need To Evaluate ◽  
Integrity Management ◽  
The North Sea ◽  
The Uk

With many offshore installations in the UK sector of the North Sea now reaching or being in excess of their original anticipated design life, there is a particular need to evaluate approaches to structural integrity management by offshore operators. Ageing processes can affect the structural integrity of the installation and demonstration of adequate performance beyond its original design life is thus a necessary requirement. This paper addresses the issues relevant to the life extension of ageing installations.

Issues for Consideration in Life Extension and Managing Ageing Facilities

2011 ◽  
Author(s):  
Solfrid Ha˚brekke ◽  
Lars Bodsberg ◽  
Per Hokstad ◽  
Gerhard Ersdal
Keyword(s):  
Oil And Gas ◽  
Point Of View ◽  
Life Extension ◽  
Original Design ◽  
Material Degradation ◽  
Safety Level ◽  
Design Life ◽  
Extended Operation ◽  
Norwegian Continental Shelf ◽  
Extension Process

A large number of facilities and parts of the infrastructure on the Norwegian Continental Shelf are approaching or have exceeded their original design life. Many fields, however, have remaining recoverable oil and gas reserves which may be profitable if the field’s life is extended. From a safety point of view, the condition of systems, structures and components may not be acceptable for extended operation. Ageing and life extension have been a top priority for the Petroleum Safety Authority Norway (PSA) and PSA has asked SINTEF to conduct a study of various aspects of ageing and life extension. The paper presents main results from the study, including how to document the safety of an ageing facility and how to uphold the safety level by means of a maintenance programme balancing three aspects of ageing: 1) Material degradation, 2) Obsolescence, i.e. operations and technology being “out of date” and 3) Organisational issues. The paper presents six main steps of the life extension process and discusses important issues to consider for operators in a life extension process.

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