A Proposed Strategy for Risk Analysis of Flexible Pipe Systems

2010 ◽  
Author(s):  
Carlos Eduardo Costa Valle Longo ◽  
Guilherme de Salles Bessa ◽  
Marcelo Brack ◽  
Ota´vio Campos de Arau´jo ◽  
Wallace Bartholomeu e Silva
Keyword(s):  
Risk Analysis ◽  
Oil And Gas ◽  
Flexible Pipe ◽  
Pipe System ◽  
Previous Definition ◽  
Integrity Management ◽  
Historic Data ◽  
Potential Failure ◽  
Pipe Systems ◽  
Definition Of

Nowadays, due to the increasing importance of the HSE and also the operational availability requirements, one of the most important challenges for producing oil and gas at subsea environments is to have a mature methodology for quantifying risks. The main objective of this paper is to present a strategy for running risk analysis of flexible pipe systems. These systems are extensively used by Petrobras to flow different kinds of fluids in deep water offshore scenarios. The strategy presented herein includes the classification of threats and the potential failure mechanisms. Probabilistic figures are established depending on the historic data of the components of the flexible pipe system and also on the theoretical results obtained from available models for determination of the component remaining life. The strategy is based on the previous definition of inference rules and technical criteria for probability, consequence and risk assessments. The final goal is to have an adequate tool to help Operators to take decisions, to establish strategies and to improve flexible pipe integrity management.

Comparative Study on the Collapse Response of Flexible Pipe Using Finite Element Methods

2014 ◽  
Author(s):  
Nathan Cooke ◽  
Shawn Kenny
Keyword(s):  
Finite Element ◽  
Mechanical Response ◽  
Numerical Data ◽  
External Pressure ◽  
Operating Conditions ◽  
Combined Loading ◽  
Flexible Pipe ◽  
Geometric Imperfection ◽  
Pipe System ◽  
Pipe Systems

Although the scope and use of flexible pipe systems in deepwater developments is expanding, the mechanical behavior for these environments is not fully understood. This is due to the complex response and interaction between multiple layers within the pipe system that introduces significant difficulties and constraints into the engineering analysis. As future developments look to extend the use of this technology to greater water depths and harsher operating conditions there is a need to develop advanced numerical tools that can evaluate the mechanical integrity of these complex hybrid pipe systems. Availability of increasingly advanced computational packages has enabled substantial improvements to be made in the complexity of simulation tools for combined loading, external pressure collapse and fretting. This study establishes a foundation for the development of advanced numerical modeling procedures to assess the collapse failure of composite flexible pipe systems for deepwater applications. Here, a continuum finite element model is constructed using the software package ABAQUS/Standard, and studied using non-linear (arc length) methods. The carcass, pressure armor and corresponding polymer layers are represented in detail and modeled with three dimensional solid brick elements in order to examine the interlayer relationships influencing collapse initiation. In many recent studies, an initial geometric imperfection in the form of general ovality is explored as the predominant bifurcation mode. A similar approach is adopted here, coupled with case studies chosen such as to facilitate validation against existing analytical and numerical data. The importance of element selection, contact mechanics, interface properties and initial imperfections on the system mechanical response and performance is presented and compared to the available literature.

Effective Improvements to Reliability Based Corrosion Management

2010 ◽  
Author(s):  
Shahani Kariyawasam ◽  
Warren Peterson
Keyword(s):  
Decision Making ◽  
Oil And Gas ◽  
Data Gathering ◽  
Effective Area ◽  
The Face ◽  
Integrity Management ◽  
Reliability Methods ◽  
Specific Growth Rates ◽  
Safe Condition ◽  
Effective Use

Reliability methods have being adopted by oil and gas operators for integrity management decisions. These methods explicitly account for all relevant uncertainties and are designed to provide consistent safety. Consequently, a risk or reliability based approach is a very appropriate basis for decision making in the face of uncertainties. However, as in the effective use of any powerful methodology the sensitivities of the method to assumptions and limitations of applicability need to be well understood. This paper presents how improvements were made to reliability based integrity program by understanding its limitations and sensitivities. First the inputs that have the highest impact on the results were identified. These inputs are the most appropriate areas for improvement and data gathering. It is also very important to understand how the results are to be used and for what purpose. The results of this particular inline inspection based reliability assessment are used to make better excavation and repair decisions. A defect-based and joint-based decision making process is essential for determining with sufficient confidence if each defect and joint is in a safe condition. Consequently, the improvements are focused on discriminating between the myriad of defects found during an inline inspection run. Distinct field characteristics of corrosion growth are also taken into account in these improvements. The paper presents the implementation of effective area methods for future integrity probabilistic evaluations. It also describes the benefit of applying defect-specific growth rates. Finally, case studies are presented to demonstrate the effectiveness of the changes.

A Z-number integrated weighted MULTIMO-ORA method for risk prioritization in FMEA

2021 ◽  
pp. 1-15
Author(s):  
Weizhong Wang ◽  
Yilin Ma ◽  
Shuli Liu
Keyword(s):  
Risk Analysis ◽  
Risk Evaluation ◽  
Oil And Gas ◽  
Weighted Average ◽  
Entropy Method ◽  
The Self ◽  
Analysis Problem ◽  
Risk Prioritization ◽  
Self Confidence ◽  
Evaluation Information

Current risk prioritization approaches for FMEA models are insufficient to cope with risk analysis problem in which the self-confidence of expert’s judgment and the deviation among risk evaluation information are considered, simultaneously. Therefore, to remedy this limitation, this paper reports an extended risk prioritization approach by integrating the MULTIMOORA approach, Z-numbers and power weighted average (PWA) operator. Firstly, the Z-numbers with triangular fuzzy numbers are applied to reflect the self-confidence and uncertainty of expert’s judgment. Next, the PWA operator for Z-numbers (Z-PWA) with similarity measure is proposed to obtain the group risk evaluation matrix by considering the influence of the deviation among risk evaluation information. Then, an extended version of MULTIMOORA method with developed entropy method is presented to calculate risk priority ranking order of each failure. Finally, the equipment failures in a certain oil and gas plant is utilized to test the extended risk prioritization approach for FMEA model. After that, the sensitivity and comparison studies are led to illustrate the availability and reliability of the proposed risk prioritization approach for FMEA based risk analysis problem.

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