Issues for Consideration in Life Extension and Managing Ageing Facilities

Author(s):  
Solfrid Ha˚brekke ◽  
Lars Bodsberg ◽  
Per Hokstad ◽  
Gerhard Ersdal

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balancing three aspects of ageing: 1) Material degradation, 2) Obsolescence, i.e. operations and technology being “out of date” and 3) Organisational issues.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.

Author(s):  
Abe Nezamian ◽  
Robert J. Nicolson ◽  
Dorel Iosif

A large number of the old oil and gas facilities have reached or exceeded their initial design life. With a continued requirement to produce oil or gas, either from the original fields or as a base for neighbouring subsea completions, many of these respective offshore installations are likely to remain operational for a period of time in the foreseeable future. The ageing offshore infrastructure presents a constant and growing challenge. Ageing is characterised by deterioration, change in operational conditions or accidental damages which, in the severe operational environment offshore, can be significant with serious consequences for installation integrity if not managed adequately and efficiently. In order to ensure technical and operational integrity of these ageing facilities, the fitness for service of these offshore structures should be maintained. The maintenance of structural integrity is a significant consideration in the safety management and life extension of offshore installations. Detailed integrity assessments are needed to demonstrate that there is sufficient technical, operational and organisational integrity to continue safe operation throughout a life extension. Information on history, characteristic data, condition data and inspection results are required to assess the current state and to predict the future state of the facility and the possible life extension. This paper presents state of art practices in life extension of existing offshore structures and an overview of various aspects of ageing related to offshore facilities, represented risk to the integrity of a facility and the required procedures and re assessment criteria for deciding on life extension. This paper also provides an overall view in the structural requirements, justifications and calibrations of the original design for the life extension to maintain the safety level by means of a maintenance and inspection programs balancing the ageing mechanisms and improving the reliability of assessment results.


Author(s):  
Erik Ho¨rnlund ◽  
Gerhard Ersdal ◽  
Rolf H. Hinderaker ◽  
Roy Johnsen ◽  
John Sharp

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.


Author(s):  
John V. Sharp ◽  
Edmund G. Terry ◽  
John Wintle

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.


2007 ◽  
Vol 47 (1) ◽  
pp. 301
Author(s):  
G.R. Keen ◽  
M.G. Sethi

ExxonMobil Australia Pty Ltd’s subsidiary, Esso Australia Resources Pty Ltd (ExxonMobil), and BHP Billiton jointly own and operate an LPG fractionation facility at Long Island Point, near Hastings in Victoria. This facility began operating in 1970 as part of the overall development of Gippsland oil and gas resources. The facility had a nominal design life of 30 years; however, the facility will be required to operate for many more years, given the significant gas reserves remaining in Bass Strait. A plan was developed to identify and progress plant facility upgrades to ensure continued, safe operation to life end. Nine separate projects with a total value in excess of A$250 million were developed and are now in various stages of progress. The key projects include: refrigerated LPG storage tank refurbishment, fire system upgrade, a new control room and control system, and plant emergency shutdown system upgrades. These projects focus on achieving high standards of safe operations and long-term reliability through application of advances in technology to ready the facilities for their remaining life.


Author(s):  
Abe Nezamian ◽  
Joshua Altmann

The ageing of offshore infrastructure presents a constant and growing challenge for operators. Ageing is characterised by deterioration, change in operational conditions or accidental damages which, in the severe operational environment offshore, can be significant with serious consequences for installation integrity if not managed adequately and efficiently. An oil field consisting of twelve well head platforms, a living quarter platform (XQ), a flare platform (XFP) and a processing platform (XPA) are the focus of this paper, providing an overview of the integrity assessment process. In order to ensure technical and operational integrity of these ageing facilities, the fitness for service of these offshore structures needs to be maintained. Assessments of the structural integrity of thirteen identified platforms under existing conditions were undertaken as these platforms are either nearing the end of their design life or have exceeded more than 50% of their design life. Information on history, characteristic data, condition data and inspection results were collected to assess the current state and to predict the future state of the facility for possible life extension. The information included but was not limited to as built data, brown fields modifications, additional risers and clamp-on conductors and incorporation of subsea and topside inspection findings. In-service integrity assessments, pushover analyses, corrosion control and cathodic protection assessments and weight control reports were completed to evaluate the integrity of these facilities for requalification to 2019 and life extension to 2030. The analytical models and calculations were updated based on the most recent inspection results and weight control reports. A requalification and life extension report was prepared for each platform to outline the performance criteria acceptance to achieve requalification until 2019 and life extension until 2030. This paper documents the methodology to assess the platform structural integrity in order to evaluate platform integrity for the remaining and extended design life. An overview of various aspects of ageing related to these offshore facilities, representing risk to the integrity, the required procedures and re assessment criteria for deciding on life extension of these facilities is presented. This paper also provides an overall view of the structural requirements, justifications and calibrations of the original design for the life extension to maintain the safety level by means of maintenance and inspection programs balancing the ageing mechanisms and improving the reliability of assessment results.


Author(s):  
Marc Aubray

To extend the life of a CANDU-6 reactor beyond its original design life requires a major investment for the replacement of reactor components (380 pressure and calandria tubes). After a preliminary technical and economical feasibility study [ref 1], Hydro-Quebec, owner of the Gentilly-2 NPP, has decided to perform a more detailed assessment to: • Get assurance that it is technically and economically viable to extend Gentilly-2 for another 20 years beyond the original design life; • Identify the detailed work to be done; • Define the overall cost and the general schedule; • Ensure an adequate licensing strategy to restart after refurbishment; • Complete all the Environmental Impact Studies required to obtain the government authorizations. Two processes have been used to assess the “health” of the station Systems, Structures and Components (SSCs): • The Plant Life Management Studies (PLIM) for approximately 10 critical SSC or families of SSC (PLIM Studies); • The Condition Assessment Studies for other SSC with a lower impact on the Plant production or safety. These two processes are briefly presented in the paper, as they were realized and applied at Gentilly-2 NPP.


2021 ◽  
Author(s):  
Dhyanjyoti Deka ◽  
Mike Campbell ◽  
Vinayak Patil ◽  
Michael Long Ge ◽  
Steve Wong ◽  
...  

Abstract The Tensioned Riser Assessment for Continued Service (TRACS) JIP develops a structured life extension process for TTR systems including single casing, dual casing, buoyancy can supported and tensioner supported TTRs. The JIP bridges regulatory and API frameworks and achieves industry consensus on analysis, inspections, and documentation. The life extension process developed in this JIP consists of detailed roadmaps that guide the operator through the different assessment steps starting from initial data gathering through to the development of the forward-looking IMP. The JIP life extension process is based on a threat assessment philosophy which ensures identification and assessment of all possible threats to the integrity of the TTR in its extended life. The JIP process is validated against three real life TTR systems that are nearing the end of their design lives. Potential threats to the integrity of these TTRs during the projected continued service beyond the design life are identified and specific inspection and analysis recommendations to safely manage or mitigate these threats are made. The JIP also provides TTR life extension analysis guidance while considering the opportunities to reduce conservatism compared to new designs. Inspection of TTRs is challenging due to accessibility issues and the pipe in pipe construction. Several subsea NDE inspection tools are surveyed in this JIP and their applicability to TTRs is discussed.


Author(s):  
Jorgen Thomas Wold Eide ◽  
Jan Muren

This paper presents a methodology for performing a lifetime assessment of flexible pipes applicable to re-qualification during the original design life and at life extension. A systematic approach is developed, providing flexible riser and flowline engineers a standardized methodology for determining the current integrity- and risk level. The objective is to provide methodology that is easy to implement, thus enabling consistent assessments of all flexible pipes in the operator’s portfolio. The methods described are taken from work performed in a recent JIP run jointly by MARINTEK/NTNU and 4Subsea, and is based on substantial experiences with lifetime assessment combined with a review of relevant guidelines and standards. Key areas are suggested for industry improvement and recommendations to further developments, to increase both efficiency and quality of the lifetime assessment process.


Author(s):  
Basim Mekha ◽  
Robin Gordon

Abstract As many offshore production systems approach the end of their original Design Life, Operators are faced with the choice of either decommissioning or demonstrating that the original Design Life can be extended (Life Extension). Life extension requires the Operator to perform detailed engineering analyses to verify that the system can be operated safely over the period of Life Extension. In many cases this requires detailed fatigue analysis and inspection programs to demonstrate that original fabrication flaws or fatigue cracks that may have existed during the welding of the riser joints or initiated over the original Design Life will not grow to a critical size resulting in failure. Engineering Critical Assessment (ECA) is now routinely applied in the design and fabrication of new offshore riser systems to develop girth weld flaw acceptance criteria. The resulting flaw acceptance criteria ensure that fabrication flaws will not extend to a critical size over the Design Life and thus the riser still meet its calculated fatigue life. Although ECA procedures for new construction are well established and standard practices have been adopted throughout the industry, ECA procedures for Life Extension have not yet evolved to the same level of acceptance. This paper will review specific issues associated with applying ECA to support Life Extension of offshore Riser Systems. The paper will provide the overall ECA philosophy and methodology for life extension to be adopted for the historical (hindcast or Phase 1) and future (forecast or Phase 2) analysis of the risers. Some thoughts will also be given to the approach implemented to take advantage of the actual weld fabrication data with the focus on the fatigue critical sections of the risers. Finally, the paper will address the requirements for riser in-situ inspection and how the results could be analyzed and applied to the life extension analysis in conjunction with the ECA analysis.


Author(s):  
Abdul Wahab Al-Mithin ◽  
Abdul Wahab Al-Ahmad ◽  
Vinayak Sardesai ◽  
G. Santhosh Kumar

The professionals across the Oil & Gas industry have strived to combat the adverse effects of Hydrogen Sulphide and maintain the integrity of vital facilities. The detrimental effects of Hydrogen Sulphide on process equipment has remained as one of the prime subject of research in Oil & Gas Industry, fostering the advancement of inspection philosophies and necessitating adoption of appropriate mitigating measures. The challenge of Integrity Management increases with the ageing of equipment and increased influx of sour media. This paper discusses: • The change in operating environment — from non sour to sour. • The actions taken to protect the equipment in the changed operating environment. • Consequent changes in the inspection strategies and techniques to detect material degradation. • Material protection methodologies deployed to manage the age old facilities for safe operation. This paper gives an insight into the various methodologies adopted in KOC to address asset/plant life extension issues of an operating company to tackle the challenges caused by the changed composition of fluids handled. The paper illustrates adoption of appropriate inspection strategies, application of effective internal coating systems, periodic online monitoring of the pressure vessels to improve confidence level with respect to integrity of the vessels without necessitating major changes in the facilities.


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