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.

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.

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.

Reliability Based Assessment for Fatigue Integrity Management

2008 ◽  
Author(s):  
M. Manzocchi ◽  
N. Shetty ◽  
A. Stacey
Keyword(s):  
System Reliability ◽  
Structural Reliability ◽  
Offshore Structures ◽  
Structural Failure ◽  
Component Reliability ◽  
Offshore Installations ◽  
Integrity Management ◽  
Inspection Techniques ◽  
Overall Reliability

Reliability analysis can be used to assess the risk of structural failure in ageing offshore installations and to subsequently optimise inspection plans. This paper describes the findings of a joint industry project to develop and implement a methodology for system reliability updating based on the results of in-service inspections. The effects of different combinations of inspection techniques, namely flooded member detection (FMD) and magnetic particle inspection (MPI), and inspection intervals on the component reliability were examined. Additionally, a case study was performed to demonstrate the system reliability of actual structures with inspection histories. A comprehensive methodology for updating the assessment of system reliability of offshore structures based on in-service inspection results was developed. The methodology allows several important features associated with system reliability, i.e. redundancy, stress redistribution and correlation between the random variables, to be accounted for. The structural reliability is given in terms of an overall reliability for combined fatigue and pushover. The study demonstrated that the methodology may be used to target inspections to those areas of the structure with low fatigue life and low redundancy.

Structural Integrity Monitoring: Review and Appraisal of Current Technologies for Offshore Applications

2008 ◽  
Author(s):  
P. May ◽  
D. Sanderson ◽  
J. V. Sharp ◽  
A. Stacey
Keyword(s):  
Structural Integrity ◽  
Health And Safety ◽  
Offshore Structures ◽  
Monitoring Methods ◽  
Regulatory Requirement ◽  
Integrity Monitoring ◽  
Monitoring Techniques ◽  
Offshore Installations ◽  
Integrity Management ◽  
Further Development

The use of structural integrity monitoring techniques on offshore installations provides the potential to reduce the risk of structural failure. The Health and Safety Executive’s (HSE’s) Offshore Division has funded a review of relevant technologies in structural integrity monitoring with potential application to offshore installations as well as practical offshore experience with structural integrity monitoring. The purpose of the study was to identify current capabilities of structural integrity monitoring techniques for structural integrity management of offshore installations (i.e. offshore jackets and semi-submersible structures used for drilling and or production operations but excluding FPSOs), to identify limitations in current approaches and identify areas for further development, to identify opportunities for technology transfer from other industries and to review and assess key research and development including current initiatives. The key structural integrity monitoring methods relevant to offshore structures were reviewed. It was found that offshore experience of structural integrity monitoring is limited to date and that all current systems are for bespoke applications. Current codes and standards refer in a limited sense to the use of structural integrity monitoring and this may influence the limited take up to date of this technology. However, there is a regulatory requirement for leak detection in ageing semi-subs as a recent introduction to DNV classification rules OSS-101 [1].

scholarly journals Integrity Management of Marine Structures; With Emphasis on Design for Structural Robustness

2018 ◽  
Author(s):  
Torgeir Moan
Keyword(s):  
Structural Damage ◽  
Structural Integrity ◽  
Oil And Gas ◽  
Offshore Structures ◽  
Design Standards ◽  
Limit States ◽  
Fabrication Errors ◽  
Integrity Management ◽  
Operational Errors ◽  
And Control

Based on relevant accident experiences with oil and gas platforms, a brief overview of structural integrity management of offshore structures is given; including an account of adequate design criteria, inspection, repair and maintenance as well as quality assurance and control of the engineering processes. The focus is on developing research based design standards for Accidental Collapse Limit States to ensure robustness or damage tolerance in view damage caused by accidental loads due to operational errors and to some extent abnormal structural damage due to fabrication errors. Moreover, it is suggested to provide robustness in cases where the structural performance is sensitive to uncertain parameters. The use of risk assessment to aid decisions in lieu of uncertainties affecting the performance of novel and existing offshore structures, is briefly addressed.

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.

Safe Operation of Jacket Platforms in a Major Oil Field in the North Sea

2018 ◽  
Author(s):  
Ingar Scherf ◽  
Trine Hansen ◽  
Gudfinnur Sigurdsson
Keyword(s):  
Emergency Preparedness ◽  
Structural Integrity ◽  
Fatigue Cracks ◽  
Regulatory Compliance ◽  
Offshore Structures ◽  
Oil Field ◽  
Inspection Planning ◽  
Original Design ◽  
Safe Operation ◽  
Integrity Management

Offshore Structures operate for decades in extremely hostile environments. It is important during this period that the structural integrity is efficiently managed to ensure continuous and safe operation. Increased use of enhanced oil and gas recovery means it is likely that many existing installations will remain operational for a significant period beyond the original design life. The operator needs to capture, evaluate and, if necessary, mitigate design premise changes which inevitably occur during the life of a structure. Further, advances in knowledge and technology may imply changes in codes and standards as well as in analysis methodologies. Changes in corporate structures, transfer of operator responsibility and retirement of experienced engineers call for reliable means to transfer historical data and experience to new stakeholders. Effective emergency preparedness capabilities, structural integrity assessments and inspection planning presuppose that as-is analysis models and corresponding information are easily accessible. This paper presents an implementation of the in-service integrity management process described in the new revision of NORSOK standard N-005 [1] for a large fleet of jackets at the Norwegian Continental Shelf. The process, comprising management of design premise changes as well as state-of-the-art technical solutions over a range of disciplines, has enabled the operator to prolong the service life with decades at minimum investments. A structure integrity management system (SIMS) has been developed and digitized over years and streamlined to meet the needs and challenges in the operation and management of the jacket platforms. SIMS enables a rather lean organization to control the structural integrity status of all load-bearing structures at any time. Platform reinforcements and modifications along with other operational risk reducing measures like unman the platforms in severe storms enable continued use with the same level of safety as for new manned platforms. Advanced analyses are used to document regulatory compliance. Modern fatigue and reliability based inspection planning analyses have reduced the costs needed for inspection of fatigue cracks significantly. The benefits from the SIMS system are substantial and the resulting safety and productivity gains are apparent. The continuity of knowledge and experience is maintained, reducing risk to safety and regularity. The digital transformation related to management of structural integrity status as described in NORSOK standard N-005 is realized through SIMS.

Developing the Structural Integrity Management System for Ageing Fixed Offshore Oil Platforms in Indonesia

2017 ◽  
Vol 862 ◽  
pp. 265-270
Author(s):  
Raditya Danu Riyanto ◽  
Murdjito
Keyword(s):  
Management System ◽  
Structural Integrity ◽  
Offshore Structures ◽  
Offshore Platforms ◽  
Offshore Structure ◽  
Element Analysis ◽  
East Kalimantan ◽  
Ranking Criteria ◽  
Life Years ◽  
Integrity Management

Offshore structure, particularly fixed offshore structures, should be kept in the performance for the fit-for-purpose condition during their operating lifetime. For fixed offshore structures that exceed their designated life years, the proper Structural Integrity Management System (SIMS) should be developed and applied. Despite the fixed offshore platforms have their service life, there are still platforms that continue to operate exceeding their service lifetime. These ageing platforms should be taken care thoroughly to avoid the consequences that could take casualties. This paper will propose the proper initiation of SIMS development for ageing fixed offshore platforms in Indonesia, by taking an example at Bekapai Field Platforms in East Kalimantan. Using HAZID technique and several ranking criteria, the platforms are assessed and ranked. Platforms that categorized in critical condition are grouped based on similarities in geometry and function. The highest rank is analyzed in computer Finite Element Analysis (FEA) Software with modification based on latest inspection result. This method is proven to be a proper method to be used as a maintenance program for ageing fixed offshore platforms in Indonesia.

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