Random Field Modeling of Rainfall-Induced Soil Movement

2002 ◽  
Author(s):  
I. Konuk ◽  
U. O. Akpan ◽  
D. P. Brennan
Keyword(s):  
Random Field ◽  
Structural Integrity ◽  
Oil And Gas ◽  
Route Planning ◽  
Software Tool ◽  
Slope Movement ◽  
Ground Movement ◽  
Spatial And Temporal Variability ◽  
Temporal Correlations ◽  
Field Modeling

Natural oil and gas transmission pipeline networks often traverse regions where potential slow ground movements may affect pipeline structural integrity. One of the primary causes of slow ground movement in any region involves the duration, amount, and intensity of rainfall. The phenomenon of rainfall-induced slow ground movement is characterized by both spatial and temporal variability, and involves uncertainties that are best modeled using a probabilistic methodology. A random field modeling strategy is formulated in this study, in which spatial and temporal correlations between rainfall and ground movement are accounted for. The random field formulation advanced in the current study has a number of significant features and capabilities, including modeling the spatial and temporal relationship between rainfall and slope movement for specified pipeline routes, predicting the likelihood of exceeding slope movement thresholds for various precipitation levels and intensities, and providing maps of risk for slope movement, which can be used as a guide in pipeline route planning, selection, and adaptation strategies for the design and maintenance of oil and gas infrastructure. These capabilities have been implemented and encapsulated into the software tool VSLOPE, which has been tested using monthly rainfall and field data for various locations.

Simulation of the Response of Buried Pipelines to Slope Movement Using 3D Continuum Modeling

2012 ◽  
Author(s):  
Abdelfettah Fredj ◽  
Aaron Dinovitzer
Keyword(s):  
Fluid Pressure ◽  
Slope Movement ◽  
Ground Movement ◽  
Ground Subsidence ◽  
Continuum Modeling ◽  
Buried Pipelines ◽  
Design Standards ◽  
Codes Of Practice ◽  
Modeling Process ◽  
Ongoing Work

Pipeline integrity is affected by the action of external soil loads in addition to internal fluid pressure. External soil loads can be generated by landslides or at sites subject to ground subsidence, heave or seismic effects. Under these varied conditions of ground movement potential pipeline safety involves constraints on design and operations. The design processes includes developing an understanding of strains that could be imposed on the pipe (strain demand) and strain limits that the pipe can withstand without failure. The ability to predict the pipeline load, stress or strains state in the presence of soil restraint and/or soil displacement induced loading is not well described in design standards or codes of practice. This paper describes the ongoing work involved in a study investigating the mechanical behavior of buried pipelines interacting with active landslides. Detailed pipe-soil interaction analyses were completed with a 3D continuum SPH method. This paper describes the LS-DYNA numerical modeling process, previously developed by the authors, which was refined and applied to site-specific conditions. To illustrate the performance of the modeling process to consider a translational slide, additional numerical model validation was completed and is described in this paper. These comparisons illustrate that good agreement was observed between the modeling results and experimental full scale trial results. Sample results of the application of the validated 3D continuum modeling process are presented. These results are being used to develop generalized trends in pipeline response to slope movements. The paper describes both the progress achieved to date and the future potential for simplified engineering design tools to assess the load or deformation capacity requirements of buried pipelines exposed to different types of slope movement.

Structural Integrity System Based on an Object-Oriented Activity- and Product Model

1993 ◽  
Author(s):  
Morten Lovstad ◽  
Tor G. Syvertsen
Keyword(s):  
Computational Models ◽  
Structural Integrity ◽  
Oil And Gas ◽  
Physical Structure ◽  
Gas Production ◽  
Structural Safety ◽  
Actual State ◽  
Product Model ◽  
The North ◽  
Analysis Models

Abstract Huge steel or reinforced concrete structures in deep waters support the installations for oil and gas production in the North Sea. Steady operations in a hostile environment require that structural safety and integrity is maintained. For rapid evaluation and assessment of structural integrity in case of modifications or urgency situations, Structural Integrity Systems are established, comprising computational models and structural analysis programs. A major problem for structural assessment at short notice is to keep the analysis models updated and consistent with the actual state of the physical structure and the loadings. This paper proposes a layered approach for model integration, which enable maintenance of the models at a high level, from which detailed analysis models are derived in a consistent manner.

scholarly journals Integrity Management of Marine Structures; With Emphasis on Design for Structural Robustness

2018 ◽  
Author(s):  
Torgeir Moan
Keyword(s):  
Structural Damage ◽  
Structural Integrity ◽  
Oil And Gas ◽  
Offshore Structures ◽  
Design Standards ◽  
Limit States ◽  
Fabrication Errors ◽  
Integrity Management ◽  
Operational Errors ◽  
And Control

Based on relevant accident experiences with oil and gas platforms, a brief overview of structural integrity management of offshore structures is given; including an account of adequate design criteria, inspection, repair and maintenance as well as quality assurance and control of the engineering processes. The focus is on developing research based design standards for Accidental Collapse Limit States to ensure robustness or damage tolerance in view damage caused by accidental loads due to operational errors and to some extent abnormal structural damage due to fabrication errors. Moreover, it is suggested to provide robustness in cases where the structural performance is sensitive to uncertain parameters. The use of risk assessment to aid decisions in lieu of uncertainties affecting the performance of novel and existing offshore structures, is briefly addressed.

Buckling Resistance of Large Diameter Spiral Welded Linepipe

2004 ◽  
Author(s):  
Tom Zimmerman ◽  
Chris Timms ◽  
Jueren Xie ◽  
James Asante
Keyword(s):  
Oil And Gas ◽  
Weld Seam ◽  
Large Diameter ◽  
Ground Movement ◽  
Finite Element Analyses ◽  
Line Pipe ◽  
Diameter Pipe ◽  
Buckling Resistance ◽  
Analytical Research ◽  
Full Scale Tests

This paper contains the results of an experimental and analytical research program to determine the compressive buckling resistance of large-diameter, spiral-welded linepipe. Buckling resistance is important for pipe intended for service in Arctic, oil and gas pipeline systems, where pipes may be subjected to high bending strains caused by various ground movement events. The experimental work consisted of four full-scale tests of 30-inch (762 mm) diameter pipe subjected to various combinations of internal pressure, axial force and bending. The pipe specimens were fabricated using two material grades (X70 and X80) and two D/t ratios (82 and 48). Finite element analyses of the four tests were conducted to develop a better understanding of specimen behavior. The results suggest that spiral welded linepipe is as good as longitudinally welded line pipe in terms of buckling capacity. The spiral weld seam was in no way detrimental to the pipe performance.

scholarly journals A modular platform for automated cryo-FIB workflows

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Sven Klumpe ◽  
Herman K H Fung ◽  
Sara K Goetz ◽  
Ievgeniia Zagoriy ◽  
Bernhard Hampoelz ◽  
...  
Keyword(s):  
Focused Ion Beam ◽  
Structural Integrity ◽  
Electron Tomography ◽  
Ion Beam ◽  
Light And Electron Microscopy ◽  
Software Tool ◽  
3 Dimensional ◽  
Improved Stability ◽  
Modular Platform ◽  
Beam Currents

Lamella micromachining by focused ion beam milling at cryogenic temperature (cryo-FIB) has matured into a preparation method widely used for cellular cryo-electron tomography. Due to the limited ablation rates of low Ga+ ion beam currents required to maintain the structural integrity of vitreous specimens, common preparation protocols are time-consuming and labor intensive. The improved stability of new generation cryo-FIB instruments now enables automated operations. Here, we present an open-source software tool, SerialFIB, for creating automated and customizable cryo-FIB preparation protocols. The software encompasses a graphical user interface for easy execution of routine lamellae preparations, a scripting module compatible with available Python packages, and interfaces with 3-dimensional correlative light and electron microscopy (CLEM) tools. SerialFIB enables the streamlining of advanced cryo-FIB protocols such as multi-modal imaging, CLEM-guided lamella preparation and in situ lamella lift-out procedures. Our software therefore provides a foundation for further development of advanced cryogenic imaging and sample preparation protocols.

Predictive Assessment of External Corrosion on Transmission Pipelines

2008 ◽  
Author(s):  
Gae¨l Pognonec ◽  
Vincent Gaschignard ◽  
Philippe Notarianni
Keyword(s):  
Growth Rate ◽  
Oil And Gas ◽  
Electrochemical Corrosion ◽  
Software Tool ◽  
Probability Of Failure ◽  
Entropy Method ◽  
Probabilistic Methods ◽  
Optimal Interval ◽  
Annual Probability ◽  
Cross Entropy Method

Oil and Gas operators have to deal with the ageing process of their transmission pipeline grid. Some of these pipelines can be inspected using In Line Inspection (ILI) tools. In order to maintain an acceptable integrity level, re-inspection operations have to be performed. This process needs to be optimized in terms of resources and cost. Gaz de France R&D Division has developed a methodology which prioritizes rehabilitation operations on a pipeline after in-line inspections, and determines the optimal interval for re-inspection. A reliable help decision software tool which applies the methodology has also been developed. Dealing with defects assimilated to external electrochemical corrosion, the developed methodology is based on: • pigs information in order to assess a probable corrosion growth rate; • probabilistic distribution of input parameters (geometrical characteristics of defects, characteristics of the pipe and corrosion growth rate); • probabilistic methods of calculation : the probability of failure is calculated with the Monte-Carlo method. The convergence of the calculation is accelerated with the Cross Entropy method. The calculation results take the form of three probabilities of failure: • a punctual probability of failure for each defect; • an annual probability of failure for each defect; • an annual probability of failure per kilometer of pipe. To interpret the results, the annual probability of failure per kilometer of pipe is then compared with threshold values.

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