Remaining Life Assessment and Life Extension of Offshore Pipelines

2018 ◽  
Author(s):  
Jens P. Tronskar
Keyword(s):  
Life Assessment ◽  
Life Extension ◽  
Remaining Life ◽  
Original Design ◽  
Offshore Pipelines ◽  
Field Development ◽  
Design Life ◽  
The Future ◽  
Cost Efficient ◽  
Remaining Life Assessment

Cost efficient offshore field development often involves tiebacks to existing field infrastructure. Efficient field development requires life extension of existing production facilities and pipelines to accommodate the new field resources over their life expectation. For fields near the tail end of their production the pipelines may be close to the end of their design life, and it must be shown that they have potential for extended life beyond the original design life until the end of the period of operation of the new field. Offshore pipelines are designed and constructed to recognized standards, such as the widely applied DNV OS-F101 2013 Submarine Pipelines Systems and earlier versions. The latest edition of the code was recently issued as a standard with some major updates and a modified code number i.e. DNVGL ST-F101 [1]. As pipelines age, they will inevitably be exposed to various types of degradation and an Operator must be able to both assess the significance of this damage and the pipeline remaining life to ensure that the pipelines do not fail as they age before the end of their design lives. Currently, many pipelines are operated far beyond the original design life and as mentioned above for cost efficient field development the pipeline operator often needs to demonstrate that the pipeline’s useful life can be extended another 10 or in some cases up to 30 years. For some pipelines, new operating conditions will be introduced by tie-in of new fields and this will impact the future rate of degradation. Hence, it cannot be assumed that the future degradation will be similar or less severe than experienced since commissioning of the pipeline. Extension of the life of the pipeline can be demonstrated by adopting methods of analysis that show the line is safe for an extended life under the future expected operating condition. This paper describes the risk based approach applied for pipeline remaining life and life extension analyses based on DNV GL codes and other relevant recommended practices. For illustration of the methodology a typical case of remaining life assessment of and life extension of a gas export pipeline is presented in the Case Study.

Introduction and Overview

1989 ◽  
pp. 1-20
Keyword(s):  
Power Plants ◽  
Failure Modes ◽  
Failure Criteria ◽  
Operating Conditions ◽  
Life Assessment ◽  
Remaining Life ◽  
Long Term Effects ◽  
Remaining Service Life ◽  
Design Life ◽  
Remaining Life Assessment

Abstract The ability to accurately assess the remaining life of components is essential to the operation of plants and equipment, particularly those in service beyond their design life. This, in turn, requires a knowledge of material failure modes and a proficiency for predicting the near and long term effects of mechanical, chemical, and thermal stressors. This chapter presents a broad overview of the types of damage to which materials are exposed at high temperatures and the approaches used to estimate remaining service life. It explains how operating conditions in power plants and oil refineries can cause material-related problems such as embrittlement, creep, thermal fatigue, hot corrosion, and oxidation. It also discusses the factors and considerations involved in determining design life, defining failure criteria, and implementing remaining-life-assessment procedures.

Late life management of onshore and offshore pipelines

2015 ◽  
Vol 55 (2) ◽  
pp. 414
Author(s):  
Brian Humphreys ◽  
Wacek Lipski
Keyword(s):  
Oil And Gas ◽  
Life Review ◽  
Remaining Life ◽  
Offshore Pipelines ◽  
Field Development ◽  
Design Life ◽  
Inspection And Maintenance ◽  
1960S And 1970S ◽  
The 1960S ◽  
Opening Up

The Australian oil and gas boom of the 1960s and 1970s lead to production commencing in the Gippsland, Surat, Cooper and Carnarvon basins and so many pipeline assets around Australia are approaching operating lives of 40-50 years and the end of their design lives. With unconventional field development and the Australian gas markets opening up to international customers through LNG, there will be an increasing requirement to extend the life of pipelines while maintaining safety and integrity. The management of pipeline assets late in their design life is a challenge for operators both onshore and offshore, with pipelines requiring higher levels of inspection and maintenance, while revenues can be fixed or regulated for downstream assets or potentially declining for upstream assets. To operate pipelines beyond their specified design life, there are requirements that must be fulfilled—for offshore, a design re-qualification in accordance with DNV-OS-F101 and for onshore, a remaining life review in accordance with AS2885.3. In addition, for onshore pipelines, AS2885.3 requires the remaining life review process to be undertaken every 10 years, rather than just at the end of the design life. This extended abstract discusses the requirements of the DNV-OS-F101 and AS2885.3 and the approaches required to meet these requirements. It also discusses key lessons that have been learned and makes recommendations to pipeline operators preparing for end-of-design-life reviews and executing them as cost effectively as possible.

Remaining Life Assessment Technology Applied to Steam Turbines and Hot Gas Expanders

2011 ◽  
Author(s):  
Phillip Dowson ◽  
David Dowson
Keyword(s):  
Fatigue Life ◽  
Oil Refinery ◽  
Life Assessment ◽  
Life Extension ◽  
Remaining Life ◽  
Steam Turbines ◽  
Hot Gas ◽  
Creep Fatigue ◽  
Assessment Technology ◽  
Remaining Life Assessment

In today’s market place, a large percentage of oil refinery, petrochemical, and power generation plants throughout the world have been trying to reduce their operation cost by extending the service life of their critical machines, such as steam turbines, beyond the design life criteria. The key ingredient in plant life extension is Remaining Life Assessment Technology. This paper will outline the Remaining Life Assessment procedures, and review the various damage mechanisms such as creep, fatigue, creep-fatigue and various embrittlement mechanisms that can occur in these machines. Also highlighted will be the various testing methods for determining remaining life or life extension of components such as high precision STR (Stress Relaxation Test), which determines creep strength, and CDR (Constant Displacement Rate) Test, which evaluates fracture resistance. Other tests such as replication/microstructure analysis and toughness tests will also be reviewed for calculating the remaining life or life extension of the components. Use of the latest computer software will also be highlighted showing how creep-life, fatigue-life and creep/fatigue-life calculations can be performed. Also shown will be an actual life extension example of a hot gas expander performed in the field.

Structural Response and Remaining Life of Damaged Composites

2015 ◽  
Vol 813-814 ◽  
pp. 106-110
Author(s):  
Dalbir Singh ◽  
C. Ganesan ◽  
A. Rajaraman
Keyword(s):  
Hybrid Approach ◽  
Experimental Studies ◽  
Structural Response ◽  
Material Behavior ◽  
Experimental Results ◽  
Life Assessment ◽  
Nonlinear Material ◽  
Remaining Life ◽  
Design Effectiveness ◽  
Remaining Life Assessment

Composites are being used in variety of applications ranging from defense and aircraft structures, where usage is profuse, to vehicle structures and even for repair and rehabilitation. Most of these composites are made of different laminates glued together with matrix for binding and now-a-days fibers of different types are embedded in a composite matrix. The characterizations of material properties of composites are mostly experimental with analytical modeling used to simulate the system behavior. But many times, the composites develop damage or distress in the form of cracking while they are in service and this adds a different dimension as one has to evaluate the response with the damage so that its performance during its remaining life is satisfactory. This is the objective of the present study where a hybrid approach using experimental results on damaged specimens and then analytical finite element are used to evaluate response. This will considerably help in remaining life assessment-RLA- for composites with damage so that design effectiveness with damage could be assessed. This investigation has been carried out on a typical composite with carbon fiber reinforcements, manufactured by IPCL Baroda (India) with trade name INDCARF-30. Experimental studies were conducted on undamaged and damaged specimens to simulate normal continuous loading and discontinuous loading-and-unloading states in actual systems. Based on the experimental results, material characterization inputs are taken and analytical studies were carried out using ANSYS to assess the response under linear and nonlinear material behavior to find the stiffness decay. Using stiffness decay RLA was computed and curves are given to bring the influence of type of damage and load at which damage had occurred.

scholarly journals The thermal history and stress state of a fresh steam-pipeline influencing its remaining service life

2011 ◽  
Vol 15 (3) ◽  
pp. 691-704 ◽  
Author(s):  
Gordana Bakic ◽  
Vera Sijacki-Zeravcic ◽  
Milos Djukic ◽  
Stevan Maksimovic ◽  
Dusan Plesinac ◽  
...  
Keyword(s):  
Service Life ◽  
Elevated Temperatures ◽  
Operating Temperature ◽  
Life Assessment ◽  
Temperature History ◽  
Significant Variable ◽  
Remaining Life ◽  
Pipe Bend ◽  
Steam Pipeline ◽  
Remaining Life Assessment

The service life of thick-walled power plant components exposed to creep, as is the case with pipelines of fresh- and re-heated steam, depend on the exhaustion rate of the material. Plant operation at elevated temperatures and at temperatures below designed temperatures all relates to the material exhaustion rate, thus complicating remaining life assessment, whereas the operating temperature variation is a most common cause in the mismatching of real service- and design life. Apart from temperature, the tube wall stress is a significant variable for remaining life assessment, whose calculation depends on the selected procedure, due to the complex pipeline configuration. In this paper, a remaining life assessment is performed according to the Larson-Miller parametric relation for a ?324?36 pipe bend element of a fresh steam-pipeline, made of steel class 1Cr0.3Mo0.25V, after 160 000 hours of operation. The temperature history of the pipeline, altogether with the pipe bend, is determined based on continuous temperature monitoring records. Compared results of remaining life assessment are displayed for monitored temperature records and for designed operating temperature in the same time period. The stress calculation in the pipe bend wall is performed by three methods that are usually applied so to emphasize the differences in the obtained results of remaining life assessment.

Comparative Study on Remaining Life Assessment of a Pressure Vessel, Working in Severe Conditions, Based on Results of Metallographic Replicas and Creep Tests

2021 ◽  
Vol 1164 ◽  
pp. 67-75
Author(s):  
Iuliana Duma ◽  
Alin Constantin Murariu ◽  
Aurel Valentin Bîrdeanu ◽  
Radu Nicolae Popescu
Keyword(s):  
Stainless Steel ◽  
Life Assessment ◽  
Petrochemical Plant ◽  
Remaining Life ◽  
Creep Tests ◽  
Experimental Creep ◽  
Asme Code ◽  
Remaining Life Assessment ◽  
Service Duration ◽  
Made In

The paper presents and compares the results on the reliability and remaining life assessment of a reactor (coxing box) from a petrochemical plant. The reactor shell is made of 16Mo5 (W1.5423) steel, with a thickness of 25 mm, plated with 3 mm thick X6CrAl13 (W1.4002) stainless steel. The assessment was made in two steps. For preliminary remnant life assessment, specifications of section VII of the ASME code was used followed by iRiS‑Thermo expert system. Further, experimental creep and metallographic replica analysis were performed. Results comparison of the two methods applied revealed a reduction of the preliminary estimated remaining live obtained using metallographic replica analysis. Based on the results obtained, the possibility to extend the service duration of the coxing box in the safety condition, using current process parameters, with of 20.000 hours was highlighted.

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.

Elevated-Temperature Life Assessment

2021 ◽  
pp. 146-166
Author(s):  
Arun Sreeranganathan ◽  
Douglas L. Marriott
Keyword(s):  
High Temperature ◽  
Elevated Temperature ◽  
Stress Relaxation ◽  
Damage Mechanics ◽  
Elevated Temperatures ◽  
Constitutive Models ◽  
Life Assessment ◽  
Remaining Life ◽  
High Temperature Components ◽  
Remaining Life Assessment

Abstract This article provides some new developments in elevated-temperature and life assessments. It is aimed at providing an overview of the damage mechanisms of concern, with a focus on creep, and the methodologies for design and in-service assessment of components operating at elevated temperatures. The article describes the stages of the creep curve, discusses processes involved in the extrapolation of creep data, and summarizes notable creep constitutive models and continuum damage mechanics models. It demonstrates the effects of stress relaxation and redistribution on the remaining life and discusses the Monkman-Grant relationship and multiaxiality. The article further provides information on high-temperature metallurgical changes and high-temperature hydrogen attack and the steps involved in the remaining-life prediction of high-temperature components. It presents case studies on heater tube creep testing and remaining-life assessment, and pressure vessel time-dependent stress analysis showing the effect of stress relaxation at hot spots.

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