Use of Capability Maturity Modelling to Ensure Ageing and Life Extension are Adequately Considered in Structural Integrity Management

2011 ◽  
Author(s):  
J. V. Sharp ◽  
G. Ersdal ◽  
D. Galbraith
Keyword(s):  
Continental Shelf ◽  
Structural Integrity ◽  
Life Extension ◽  
Capability Maturity ◽  
Offshore Installations ◽  
Ageing Processes ◽  
Integrity Management ◽  
Norwegian Continental Shelf

An increasing number of offshore installations are in the life extension stage of life, with ageing processes needing to be taken into account. This is particularly important for structural integrity. Capability Maturity Modelling enables the levels of maturity in processes associated with the management of ageing to be identified and improved if required. The paper describes the model and how it has been used for assessing the management of structural integrity for installations on the Norwegian Continental Shelf.

Assessment of Ageing Structures: Case Studies

2011 ◽  
Author(s):  
Einar Landet ◽  
Narve Oma ◽  
Gerhard Ersdal ◽  
Gudfinnur Sigurdsson ◽  
Trond So̸rensen
Keyword(s):  
Service Life ◽  
Continental Shelf ◽  
Case Studies ◽  
Structural Integrity ◽  
Life Extension ◽  
Extension Phase ◽  
Harsh Environments ◽  
Safety Level ◽  
Norwegian Continental Shelf

In all phases of the service life of a structure, uncertainties will occur, hence probability based methodologies may be an important and valuable tool in order to verify structural integrity and the corresponding expected safety level. This paper gives a brief description of an approach for how to demonstrate the safety of facilities in the life extension phase by the use of risk based inspection (RBI) plans. This is illustrated with four separate cases used for assessment and life extension of FPSOs operating in harsh environments on the Norwegian continental shelf (NCS). The assessments are partly based on the methodology introduced in NORSOK (2009).

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.

Structural Integrity Management Framework for Mobile Installations

2011 ◽  
Author(s):  
A. Stacey ◽  
J. V. Sharp
Keyword(s):  
Structural Integrity ◽  
Hazard Identification ◽  
Management Policy ◽  
Audit Review ◽  
Offshore Installations ◽  
Safety Case ◽  
Integrity Management ◽  
Policy Objectives ◽  
Systems Maintenance ◽  
The Uk

This paper presents a primary integrity management (PIM) framework for mobile installations (semi-submersibles and self elevating installations) and permanently moored floating installations (FPSOs, FSUs, etc.). The primary integrity of self-elevating and floating installations depends on both the primary structure and additional systems. The framework is based upon the UK regulatory requirements for offshore installations, including the need for a thorough review of the safety case accounting for any changes in condition and future plans and verification of the primary integrity management (PIM) process. Requirements and guidance are provided for all aspects of the integrity management process covering: • primary integrity hazard identification and risk control; • resources, organisation and management, including competency assurance; • information management and documentation; • primary integrity management policy, objectives and strategy; • inspection, examination and testing; • evaluation of structure and other primary systems; • maintenance, repair and upkeep; • audit, review and continual improvement. The framework also contains guidance based on the application of existing standards and industry published documents. Finally, guidance is given on the implementation of the framework.

Hull Structure Integrity Management in Floating Structures–FSO Puteri Dulang Case

2014 ◽  
Vol 69 (7) ◽  
Author(s):  
Ajith Kumar Thankappan ◽  
M. Fazli B. M. Yusof
Keyword(s):  
Fatigue Life ◽  
Structural Integrity ◽  
Structural Response ◽  
Offshore Structures ◽  
Design Phase ◽  
Floating Structures ◽  
Offshore Installations ◽  
Hull Structure ◽  
Integrity Management ◽  
New Buildings

This paper highlights the key differences in practices employed in managing hull structure integrity of permanently moored floating offshore structures as against sailing vessels which are subject to periodic dry docking. During the design phase, the structural integrity management over the life of a sailing vessel is primarily taken into account by means of Class prescribed Nominal Design Corrosion Values which are added to minimum scantling requirements calculated based on strength and fatigue criteria. In contrast, for permanently moored offshore installations like FPSOs, FSOs etc. the hull structure integrity over the entire design life of the asset is a key design consideration both for new buildings and conversions. Analytic methods and tools (primarily those developed by Class Societies) are available to evaluate the strength requirements (based on yielding, buckling and ultimate strength criteria) and fatigue life of the hull structure. Typically three levels of analysis with increasing degree of complexity and analysis time are used to predict the structural response and fatigue life of the Hull during design phase. The degree of detailed analysis required needs to be determined in light of the expected optimization in terms of savings in scantlings for new building or for steel renewal requirements in case of conversions.

Criticality Rating of Ageing Fixed Offshore Structures

2011 ◽  
Author(s):  
S. Gupta ◽  
D. Sanderson ◽  
A. Stacey
Keyword(s):  
Structural Integrity ◽  
Offshore Structures ◽  
Structural Failure ◽  
Offshore Installations ◽  
Integrity Management

The effective structural integrity management of the ever-increasing population of ageing offshore installations on the UKCS requires the identification of key parameters which provide a measure of the criticality of installations to structural failure, thus enabling priorities to be set. This paper describes a model for the evaluation of the criticality rating of fixed offshore installations.

Fatigue Life Extension of Offshore Structures by Ultrasonic Peening

2011 ◽  
Author(s):  
Luis Lopez Martinez
Keyword(s):  
Fatigue Life ◽  
Service Life ◽  
Fatigue Resistance ◽  
Structural Integrity ◽  
High Stress ◽  
Offshore Structures ◽  
Life Extension ◽  
Original Design ◽  
Ultrasonic Peening ◽  
Offshore Installations

The service life of offshore installations is limited by its structural integrity. Furthermore the structural integrity is mainly governed by the fatigue resistance of critical welded details. In a FPSO installation these details are among others pallet stools weld joints to deck structure and bulkheads/web frames weld connections to longitudinal in ballast tanks. ultrasonic peening can improve the fatigue resistance of welded joints. Fatigue test results shows an increase of four times for high stress ranges and up to ten times for high cycle fatigue. For specimens which have already consumed half of their fatigue life the treatment resets the clock to zero, as a minimum value. Consequently ultrasonic peening treatment was applied to several offshore installations on fatigue sensitive weld connections with the objective to extend the service life of the these. Finite Element Analysis carried out by classification societies for these offshore structures demonstrated critical fatigue lives for several weld connections. These weld connections were then treated by ultrasonic peening with the objective to extend their fatigue lives and by doing that reach the targeted service life for the installation. The successful application of the ultrasonic peening treatment was a pioneering work which involved several partners. A pilot project on a FPSO started in 2005 and the treated critical weld connections are still intact and show not sign of crack initiation despite the fact the calculations then showed shorter fatigue lives than the life span already consumed. As a result the same ultrasonic peening procedure has been proposed to be applied for other fatigue sensitive locations on the installation. Offshore installations around the world are reaching their original design life. Most of the operators chose to extend the service life of their assets rather than scrape them and build new. The reasons for that are: improved oil recovering techniques, time required to get a new build installation on site, environment concerns, wiser management of energy and resources among others. Therefore the Life Extension of Offshore Installations is a subject of current interest for the upstream industry.

Structural Integrity Management Framework for Fixed Jacket Structures

2008 ◽  
Author(s):  
A. Stacey ◽  
M. Birkinshaw ◽  
J. V. Sharp ◽  
P. May
Keyword(s):  
Structural Integrity ◽  
Good Practice ◽  
Offshore Structures ◽  
Management Framework ◽  
Offshore Installations ◽  
Jacket Structures ◽  
Integrity Management ◽  
Offshore Industry

In recent years, a significant amount of effort has been expended by HSE and the offshore industry on the development of good practice for structural integrity management in the new code for offshore structures, ISO 19902. However, a review of the structural integrity management of fixed offshore installations operated on the UKCS has indicated that duty holders adopt varying approaches, in terms of both the methods used and effectiveness. The elements of a framework for the management of the structural integrity of fixed jacket structures are presented.

Development of Key Performance Indicators for Offshore Structural Integrity

2008 ◽  
Author(s):  
J. V. Sharp ◽  
G. Ersdal ◽  
D. Galbraith
Keyword(s):  
Performance Indicators ◽  
Structural Integrity ◽  
Performance Standards ◽  
Key Performance Indicators ◽  
Offshore Structures ◽  
Life Extension ◽  
Offshore Installations ◽  
Incident Rate ◽  
Safety Systems ◽  
Incident Rates

Key performance indicators (KPIs) are widely used to assess performance against targets, whether these be technical, environmental or financial. Offshore KPIs are used by both duty holders and regulators to assess the reliability of equipment and systems, often they relate to safety systems and the regulator’s interest relates to such systems. The most obvious KPIs include number of fatalities, fatal accident rate, lost time injury frequency and total recordable incident rate, as well as hydrocarbon release incident rates associated with maintaining safety. Many of the “non-headline” KPIs relate to systems that could be critical in the event of an accident and these are of great importance. However KPIs have not yet been developed for the performance of the offshore structural system. Performance standards are a requirement of current UK offshore legislation, although these again are more normally associated with fire and explosion. Since many offshore installations are now in the ageing phase performance measures are increasingly important. This paper described the background to developing KPIs for offshore structures, relating to aspects which are important for both safety and asset integrity. This has been achieved based on a hazard approach, which includes extreme weather, fatigue, corrosion and accidental damage. KPI’s need to be measurable and this aspect has been incorporated in their development. It is proposed that these KPIs will have significant use in providing a basis for measuring structural performance, particularly for ageing installations where a case for life extension needs to be made.

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