THE EFFECT OF EXTREME CORROSION DEFECT ON PIPELINE REMAINING LIFE-TIME
DOI:
https://doi.org/10.11113/mjce.v20.15756Keywords:
Ion shower, Polyethylene, Polyimide, Surface modification, Wettability, Peak-Over-Threshold, extreme data, corrosion, pipelines, probabilisticAbstract
Inspection data obtained from in-line inspection can be used to assess present integrity as well as to predict future integrity of corroding pipeline by using a combination of probabilistic analyses and simulation process. However, numerical errors arise when all the inspection data including non-extreme and extreme measured defects were used. In this study, a combination of an extreme value distribution and peaks-over-threshold method was adopted to analyse the effect of extreme data upon pipeline reliability. The paper focuses on the elimination of the “low-risk†data in the analysis in order for extreme values to be significantly emphasized. The study found that the high threshold value would lead to the high failure probability. The optimum threshold value is constrained by the number of remaining data. The selection of threshold and extreme distribution value must be cautiously carried out to minimise the possibilities of over predict the pipeline’s time to failure.References
Batte A.D., Fu B., Kirkwood M.G. and Vu D. (1997), New Methods for Determining the Remaining Strength of Corroded Pipelines, Pipeline Technology, V, pp. 221-228.
Coles S. and Tawn, J. (1996), A Bayesian Analysis of Extreme Data Rainfalls, Applied. Statistic, 45(4), pp. 463–478.
DNV (Det Norske Veritas) (1999), Recommended Practice RP-F101 for Corroded Pipelines 1999, Norway: Det Norske Veritas.
Embrechts P., Kluelberger C. and Mikosch T. (1997), Modelling Extreme Events. Berlin: Springer. 10-36.
Emmer S., Kluelberger C. and Trustedt M. (1998), VAR-A Measure of the Extreme Risk, Solutions, 2, pp. 53–63.
Falka M. and Reissb R.D (2001), Estimation of Canical Dependence Parameters in a Class of Bivariate Peaks-Over-Threshold Models, Statistics & Probability
Letters, 52, pp. 233– 242.
Ferreira J.A. and Guedes Soares C. (1998), An Application of the Peaks Over Threshold Method to Predict Extremes of Significant Wave Height, Journal of Offshore Mechanics and Arctic Engineering, 120(3), pp.165–176.
Hellevik S.G. and Langen I. (2000a), In-Service Inspection Planning of Flow lines Subjected to CO2 Corrosion, Seattle, USA: ISOPE 2000, Proceedings of the 10th International Offshore and Polar Engineering Conference, May 28-June 2. Vol
IV, pp. 372-379.
Hellevik S.G. and Langen I. (2000b), Optimal Design-Phase Inspection and Replacement Planning of Pipelines Subjected to CO2 Corrosion, International Journal of Offshore and Polar Engineering, 10(2), pp. 123-130.
Jiou G., Sotberg T., Bruschi R. and Igland R.T. (1997), The SUPERB Project-Line pipe Statistical Properties and Implications in Design of Offshore Pipelines, ASME Pipeline Technology, V, pp.45-51.
Longin F. and Solnik B. (2001), Extreme Correlation Structure of International Equity Markets, Journal of Finance, December Issues, pp.20-23.
Melchers R.E (1987), Structural Reliability Analysis and Prediction. 2nd Edition, Chichester, UK: Ellis Herwood.
Moon Y., Lall U. and Bosworth K.(1993), Comparison of Tail Probability Estimators for Flood Frequency Analysis, Journal of Hydrology, 151(2-4), pp.343 –363.
Onoz B. and Bayazit M. (2001), Effect of the Occurrence Process of the Peaks Over Threshold on the Flood Estimates, Journal of Hydrology, 244. pp.86-96.
Smith, J. (1991), Estimating the Upper Tail of Good Frequency Distributions, Water Resources, 23(8), pp.1657–1666.
Sotberg T., Moan T., Bruschi R., Guoyang J. and Mork K.J. (1997), The SUPERB Project , Recommended Target Safety Levels for Limit State Based Design of Offshore Pipelines, ASME Pipeline Technology, V, pp.71-77.
Thiruvengadam, A. (1972), Corrosion Fatigue at High Frequencies and High
Hydrostatic Pressures. Stress Corrosion Cracking of Metals-A State of the Art,
Philadelphia: ASTM Special Technical Publication.
Wolfram J. and Yahaya N. (1999), On the Effect of Some Uncertainties on the Structural Integrity Assessment of Corroding Pipelines, St Johns, Newfoundland, Canada: Proceedings of 17th International Conference Offshore Mechanics and Arctic
Engineering. Paper OMAE-99-6032, 11-16th July, pp.1-10.
Yahaya N. (1999), The Use of Inspection Data in the Structural Assessment of Corroding Pipelines, Heriot-Watt University, Edinburgh: PhD Thesis.
Yahaya N. and Wolfram, J. (1999 ), The Application of Peaks-Over-Threshold Approach on the Structural Reliability of Corroding Pipeline, Jurnal Teknologi, 30, pp.51-68.
