The oil and gas industry involves large projects with large amounts of uncertainty, including global supply, demand and price of hydrocarbon fuels. Because of these uncertainties, decisions about offshore infrastructure (design, installation, operations and cost) involve probabilities of the infrastructure to operate as intended for specified lifespans. Probability, statistics and uncertainty are fundamental to making decisions regarding offshore field development, operations and decommissioning.

Probability theory and statistics, structural safety, system reliability, safety index, Limit State function, reliability methods, Goodness-of-fit tests, Monte-Carlo simulation, etc. Also included are practical assignments and presentations on the application of course materials in the offshore industry.

None

1. Introduction to safety and reliability of engineering systems (3 hours)
- Sources of uncertainty
- Effects of uncertainty on decision making

2. Basic concepts of safety and reliability (3 hours)
- General concepts
- Time-variant versus time-invariant reliability
- Safety factor versus safety index
- Asymptotic coefficient of variation of system supply

3. Modelling of random variables and random functions (6 hours)
- Random variables and Random Functions
- Commonly used types of distributions
- Statistical analyses
- Goodness of Fit Tests
- Goodness of Fit Tests at Tails

4. Reliability methods (6 hours)
- Accurate methods
- Direct integration
- Monte-Carlo simulation
- Variance reduction techniques
- Importance sampling techniques
- Over-sampling and under-sampling

5. Reliability methods: Approximate methods (6 hours)
- Distributions of objective functions
- Approximate limit-state functions
- FOSM and Advanced FOSM
- Response surface methodology

6. Reliability of engineering systems

7. Engineering data bank and calibration of design codes
- Level of risks
- Level of codes
- Code formats
- Types of limit-state functions
- Code calibration processes

8. Application to fixed offshore platforms: identification of reliability components (6 hours)
- Uncertain loading parameters: sea state and payload
- Uncertain strength parameters: soil properties, scour, soil subsidence, material strength, damaged and corroded structural members, tubular joint cracks
- Uncertain structural model: structural modification, topside extension, additional conductors or risers

9. Application to fixed offshore platforms: reliability system of platform structure (9 hours)
- Limit-state function of reliability system
- Analytical reliability system: series and parallel systems
- Reliability Block Diagrams (RBD)
- Fault Tree Analysis (FTA) and Event Tree Analysis (ETA)
- Probability of failure
- Application of some reliability methods
- Repairable

None

Lecture notes and technical papers

[1] Alfredo H-S. Ang and Wilson H. Tang, Probability Concepts in Engineering and Design, Volume I – Basic Principles, John Wiley & Sons, New York, 1975.
[2] Alfredo H-S. Ang and Wilson H. Tang, Probability Concepts in Engineering and Design, Volume II – Decision, Risk, and Reliability, John Wiley & Sons, New York, 1984.
[3] W. Ouypornprasert, Structural Safety and Reliability, Lecture Notes, Department of Civil Engineering and Environments, Rangsit University.
[4] W. Ouypornprasert, Goodness-of-Fit Tests for Continuous Distributions Commonly Used in Civil Engineering, Working Report, Department of Civil Engineering and Environments, Rangsit University, 2001.
[5] W. Ouypornprasert, Methods to Calculate Structural Reliability, Internal Working Report No. 18, Institute of Engineering Mechanics, University of Innsbruck, 1988.
[6] Reliability methods in Mechanical and Structural Design by P.H. Wirsching, 1989, short course notes
[7] Reliability Engineering and Risk Analysis by Bernhard Stahl, 1986, in ‘Planning and Design of Fixed Offshore Platforms’ Part II Section 5, edited by B. McCleland and M.D.
Reifel, Van Nostrand Reinhold Company, N.Y 10003
[8] Handbook of Offshore Engineering Vol 1.,edited by S. Chakrabarti, Elsevier 2005, Chapter 5
[9] Offshore Application & Sensitivity Study, Offshore Technology, Report – OTO 2000 039, 2000, Health Safety Exceutive
[10] Structural Reliability Theory and its applications, Ch. 12 Application to Fixed Offshore Structures’, by M.J. Baker, Rainbow-Bridge Book, 1982

[1] Reliability Engineering and System Safety
[2] Structural Safety

The final grade will be computed according to the following weight distribution: mid-semester exam (50%), assignments/projects (20%) and final examination (30%).