Reliability assessment and calibration of ISO-LRFD factors for minimum facility offshore platfrom in Malaysia

In recent time, the offshore oil and gas industry is facing many challenges like ferocious competition from shale field operators and alternative energy sources, production drop, rising cost etc. All these factors play major role in low crude oil prices. To combat these challenges, the operators are...

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Main Author:	Fakhruddin, Khalid Ahmed
Format:	Thesis
Language:	English
Published:	2019
Subjects:	TA Engineering (General) Civil engineering (General)
Online Access:	http://eprints.utm.my/id/eprint/81062/1/KhalidAhmedMSKA2019.pdf
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id	my-utm-ep.81062
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spelling	my-utm-ep.810622019-07-24T03:06:42Z Reliability assessment and calibration of ISO-LRFD factors for minimum facility offshore platfrom in Malaysia 2019-01 Fakhruddin, Khalid Ahmed TA Engineering (General). Civil engineering (General) In recent time, the offshore oil and gas industry is facing many challenges like ferocious competition from shale field operators and alternative energy sources, production drop, rising cost etc. All these factors play major role in low crude oil prices. To combat these challenges, the operators are focusing on several untapped field with low production capacity, known as “Marginal Fields” that require innovative design approach to make it economically viable. Minimum facility platform is promising solutions for marginal fields; however, reliability of such structure is a major concern among the operators. In most of the past studies, the reliability technique is effective applied on four (4) legged jacket structure for optimization. This research has attempt to apply reliability analysis method to Mono-tower structure, as minimum facility platform for marginal fields around Malaysia region. The structure was designed as per API RP 2A (WSD). The maximum wave height and current data from Malaysian offshore is using to generate random variables as per Weibull distribution and Monte Carlo Simulation (MCS) have been developed. The surface modelling and curve fitting is done to develop quadrilateral equation in MATLAB for environmental load modelling. Design cases developed as per API RP 2A or ISO19902 must provide adequate levels of reliability throughout the service life. A combination of engineering technique i.e. component based reliability analysis and safety factors, used to ensure integration of all types of uncertainties such as loads, structural properties as resistance, failure modes. FEM method is use for accurate modelling. The probability of failure and reliability index of critical members and other structural members of interest was determined with First Order reliability Method (FORM). The fluctuation in loads and variation material properties were accounted in the assessment. The target reliability level can be achieved either by comparing with existing traditional jacket structure or by following analytical probabilistically models. The partial factors evaluated using reliability assessment is in accordance with concept of Load Resistance Factor Design (LRFD) presented in ISO-19902. Further, the ISO recommendations are followed to calibre the factors as per regional climatic conditions. The estimated reliability Index is 3.95 and probability of failure (Pof) is 5.3x10-5 as per reliability analysis results. Therefore, the conclusion is that Mono-tower as minimum facility platform is suitable for marginal field development that is fulfilling the requirement of reliability, safety and certification. The minimum structure demonstrates equal or higher reliability index for selected members as per ISO. The environmental load calibration has result in factor of 1.26, as against 1.35 suggested by ISO, indicates the potential reduction for Malaysian region without compromising the safety level of structure. 2019-01 Thesis http://eprints.utm.my/id/eprint/81062/ http://eprints.utm.my/id/eprint/81062/1/KhalidAhmedMSKA2019.pdf application/pdf en public http://dms.library.utm.my:8080/vital/access/manager/Repository/vital:125015 masters Universiti Teknologi Malaysia, Faculty of Engineering - School of Civil Engineering Faculty of Engineering - School of Civil Engineering
institution	Universiti Teknologi Malaysia
collection	UTM Institutional Repository
language	English
topic	TA Engineering (General) Civil engineering (General)
spellingShingle	TA Engineering (General) Civil engineering (General) Fakhruddin, Khalid Ahmed Reliability assessment and calibration of ISO-LRFD factors for minimum facility offshore platfrom in Malaysia
description	In recent time, the offshore oil and gas industry is facing many challenges like ferocious competition from shale field operators and alternative energy sources, production drop, rising cost etc. All these factors play major role in low crude oil prices. To combat these challenges, the operators are focusing on several untapped field with low production capacity, known as “Marginal Fields” that require innovative design approach to make it economically viable. Minimum facility platform is promising solutions for marginal fields; however, reliability of such structure is a major concern among the operators. In most of the past studies, the reliability technique is effective applied on four (4) legged jacket structure for optimization. This research has attempt to apply reliability analysis method to Mono-tower structure, as minimum facility platform for marginal fields around Malaysia region. The structure was designed as per API RP 2A (WSD). The maximum wave height and current data from Malaysian offshore is using to generate random variables as per Weibull distribution and Monte Carlo Simulation (MCS) have been developed. The surface modelling and curve fitting is done to develop quadrilateral equation in MATLAB for environmental load modelling. Design cases developed as per API RP 2A or ISO19902 must provide adequate levels of reliability throughout the service life. A combination of engineering technique i.e. component based reliability analysis and safety factors, used to ensure integration of all types of uncertainties such as loads, structural properties as resistance, failure modes. FEM method is use for accurate modelling. The probability of failure and reliability index of critical members and other structural members of interest was determined with First Order reliability Method (FORM). The fluctuation in loads and variation material properties were accounted in the assessment. The target reliability level can be achieved either by comparing with existing traditional jacket structure or by following analytical probabilistically models. The partial factors evaluated using reliability assessment is in accordance with concept of Load Resistance Factor Design (LRFD) presented in ISO-19902. Further, the ISO recommendations are followed to calibre the factors as per regional climatic conditions. The estimated reliability Index is 3.95 and probability of failure (Pof) is 5.3x10-5 as per reliability analysis results. Therefore, the conclusion is that Mono-tower as minimum facility platform is suitable for marginal field development that is fulfilling the requirement of reliability, safety and certification. The minimum structure demonstrates equal or higher reliability index for selected members as per ISO. The environmental load calibration has result in factor of 1.26, as against 1.35 suggested by ISO, indicates the potential reduction for Malaysian region without compromising the safety level of structure.
format	Thesis
qualification_level	Master's degree
author	Fakhruddin, Khalid Ahmed
author_facet	Fakhruddin, Khalid Ahmed
author_sort	Fakhruddin, Khalid Ahmed
title	Reliability assessment and calibration of ISO-LRFD factors for minimum facility offshore platfrom in Malaysia
title_short	Reliability assessment and calibration of ISO-LRFD factors for minimum facility offshore platfrom in Malaysia
title_full	Reliability assessment and calibration of ISO-LRFD factors for minimum facility offshore platfrom in Malaysia
title_fullStr	Reliability assessment and calibration of ISO-LRFD factors for minimum facility offshore platfrom in Malaysia
title_full_unstemmed	Reliability assessment and calibration of ISO-LRFD factors for minimum facility offshore platfrom in Malaysia
title_sort	reliability assessment and calibration of iso-lrfd factors for minimum facility offshore platfrom in malaysia
granting_institution	Universiti Teknologi Malaysia, Faculty of Engineering - School of Civil Engineering
granting_department	Faculty of Engineering - School of Civil Engineering
publishDate	2019
url	http://eprints.utm.my/id/eprint/81062/1/KhalidAhmedMSKA2019.pdf
_version_	1747818301513269248

Reliability assessment and calibration of ISO-LRFD factors for minimum facility offshore platfrom in Malaysia

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