An Emerging Methodology of Slope Hazard Assessment for Natural Gas Pipelines

2000 ◽  
Author(s):  
Z. Joe Zhou ◽  
Bill Liu ◽  
Gregg O’Neil ◽  
Moness Rizkalla
Keyword(s):  
Natural Gas ◽  
Public Information ◽  
Ground Movement ◽  
Management Approach ◽  
Hazard Management ◽  
Slope Movements ◽  
Natural Gas Pipelines ◽  
Site Investigations ◽  
The Impact ◽  
Ranked List

TransCanada Pipelines Ltd. (TransCanada) operates approximately 37,000 km of natural gas gathering and transmission pipelines. Within the Alberta portion of this system there are almost 1100 locations where the pipeline(s) traverse slopes, primarily as the line approaches and exits stream crossings. In the past, the approach to managing the impact of slope movements on pipeline integrity has been reactive; site investigations and/or monitoring programs would only be initiated once the slope movements were sufficiently large so as to easily observe cracking or scarp development. In some cases these movements could lead to a pipeline rupture. To move to a proactive hazard management approach and to optimize the maintenance expenditure, TransCanada has developed a new slope assessment methodology. The objective of this methodology is to establish a risk-ranked list of slopes upon which maintenance decisions can be based. Using only internal and public information on site conditions as input to predictive models for rainfall-ground movement and pipe-soil interaction, a probability of pipeline failure can be generated for each slope. Estimates of risk using a consequence-matrix approach enabled the compilation of a risk-ranked list of hazardous slopes. This paper describes this methodology, and its implementation at TransCanada, and presents some of the results.

Identification and Mitigation of a Landslide Threatening Four Operating Natural Gas Pipelines

2020 ◽  
Author(s):  
Amir Ahmadipur ◽  
Alexander McKenzie-Johnson ◽  
Ali Ebrahimi ◽  
Anthony H. Rice
Keyword(s):  
Natural Gas ◽  
Landslide Hazard ◽  
Management Process ◽  
Gas Pipelines ◽  
Hazard Management ◽  
Natural Gas Pipelines ◽  
South Central ◽  
Subsurface Investigation ◽  
Landslide Stabilization

Abstract This paper presents a case study of a landslide with the potential to affect four operating high-pressure natural gas pipelines located in the south-central US state of Mississippi. This case study follows a landslide hazard management process: beginning with landslide identification, through pipeline monitoring using strain gauges with an automated early alert system, to detection of landslide movement and its effects on the pipeline, completion of a geotechnical subsurface investigation, conceptual geotechnical mitigation planning, landslide stabilization design and construction, and stress relief excavation. Each step of the landslide hazard management process is described in this case study.

Management of Ground Movement Hazards: An Overview of a JIP

2020 ◽  
Author(s):  
Yong-Yi Wang ◽  
Don West ◽  
Doug Dewar ◽  
Alex Mckenzie-Johnson ◽  
Steve Rapp
Keyword(s):  
Best Practice ◽  
Major Elements ◽  
Ground Movement ◽  
Management Approach ◽  
Hazard Management ◽  
Ground Movements ◽  
Strain Design ◽  
Hazard Avoidance ◽  
Actual Field ◽  
Girth Welds

Abstract Ground movements such as landslides, subsidence, and settlement can pose serious threats to the integrity of pipelines. The consequences of a ground movement event can vary greatly. Certain types of ground movements are slow-moving and can be monitored and mitigated before a catastrophic failure. Other forms of ground movements can be difficult to predict. The most effective approach could be hazard avoidance, proactive means to reduce strain demand on pipelines, and/or building sufficiently robust pipeline segments that have a high tolerance to the strain demand. This paper provides an overview of a Joint Industry Project (JIP) aimed at developing a best-practice document on managing ground movement hazards. The hazards being focused on are landslides and ground settlement, including mine subsidence. This document attempts to address nearly all major elements necessary for the management of such hazards. The most unique feature of the JIP is that the scope included the hazard management approach often practiced by geotechnical engineers and the fitness-for-service assessment of pipelines often performed by pipeline integrity engineers. The document developed in the JIP provides a technical background of various existing and emerging technologies. The recommendations were developed based on a solid fundamental understanding of these technologies and a wide array of actual field experiences. In addition to the various elements involved in the management of ground movement hazards, the JIP addresses some common misconceptions about the adequacy of codes and standards, including: • The adequacy of design requirements in ASME B31.4 and B31.8 with respect to ground movement hazards, • The adequacy of linepipe standards such as API 5L and welding standards such as API 1104 for producing strain-resistant pipelines, • The proper interpretation of the longitudinal strain design limit of 2% strain in ASME B31.4 and B31.8, and • The effectiveness of hydrostatic testing in “weeding out” low strain tolerance girth welds.

Probability Calculation of Equipment Impact Based on Reliability Method

2014 ◽  
Author(s):  
Jiang Lu ◽  
Wen Wu ◽  
Zhenyong Zhang ◽  
Jinyuan Zhang
Keyword(s):  
Natural Gas ◽  
Survey Data ◽  
Fault Tree ◽  
Gas Pipelines ◽  
Impact Frequency ◽  
Dense Population ◽  
Natural Gas Pipelines ◽  
Reliability Based Design ◽  
Probability Calculation ◽  
The Impact

In order to apply the Reliability Based Design and Assessment (RBDA) methodology to evaluate the equipment impact on the onshore natural gas transmission pipelines in China, a research project was undertaken by China Petroleum Pipeline Engineering Corporation (CPPE) based on the framework developed by C-FER Technologies (C-FER) in “Guidelines for Reliability Based Design and Assessment of Onshore Natural Gas Pipelines” (sponsored by PRCI). The objective of the project was to collect native data and calibrate the probability models[1] in order to make it suitable for the situations in China where there is dense population and many newly-built high pressure and large diameter pipelines. The equipment impact model consists of two components: a) the impact probability model which calculates the frequency of mechanical interference by excavation equipment; and b) the failure model which calculates the probability of failure in a given impact. A detailed survey was undertaken in 2012 in order to collect the data required to calculate the impact frequency and the load applied by an excavator to a pipeline. The survey data for impact frequency calculation was gathered based on 19,300km of transmission pipelines from 4 operating companies in China. They reflect current prevention practices and their effectiveness. The frequencies of basic events summarized in this survey used to calculate the probabilities of the fault tree are generally agreement with the data summarized in PRCI’s report. The impact frequencies calculated by the fault tree under typical prevention measures are 400%, 200%, 20% and 0% higher than that in PR-244-9910 report for class 1, class 2, class 3 and class 4 areas respectively, which is due to dense population and more construction activities. Bucket digging forces of 321 types of excavators from 20 manufacturers were gathered. The survey data of the forces are slightly higher than that in the PR-244-9729 report as a whole due to the increase in mechanical efficiency of excavators in recent years. The excavator maximum quasi-static load model was calibrated correspondingly. Equipment impact probability calculation and model sensitivity analysis results are described to present several characteristics of onshore transmission natural gas pipelines in China.

scholarly journals Modified Leakage Rate Calculation Models of Natural Gas Pipelines

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Qingmin Hou ◽  
Daheng Yang ◽  
Xiaoyan Li ◽  
Guanghua Xiao ◽  
Siu Chun Michael Ho
Keyword(s):  
Natural Gas ◽  
Flow Rate ◽  
Leakage Rate ◽  
Rate Change ◽  
Feedback Effect ◽  
Gas Pipelines ◽  
Natural Gas Pipelines ◽  
Pipe Model ◽  
Flow Rate Change ◽  
The Impact

The leakage rate is an essential parameter for the risk assessment and failure analysis of natural gas pipelines. The leakage rate of a natural gas pipeline should be calculated quickly and accurately to minimize consequences. First, in this study, models to estimate the leakage rate of natural gas pipelines are reclassified, and the theoretical range of application for each model is also analysed. Second, the impact of the leakage on the flow rate upstream of the leak point is considered, and the method of successive approximation is used to realize this feedback effect of flow rate change. Then, a modified hole-pipe model is developed to calculate the natural gas leakage rate in this paper. Compared with the leakage rate calculated by the hole-pipe model, the leakage rate calculated by the modified hole-pipe model is smaller and closer to the actual leakage rate due to the consideration of the feedback effect of the flow rate change. Finally, the leakage rate curves of the hole-pipe model and the modified hole-pipe model under different d/D conditions are obtained through simulation. The simulation results show that the modified hole-pipe model is able to calculate the leakage rate of any leak aperture, such as the hole-pipe model, and also at a higher accuracy level than the hole-pipe model.

scholarly journals Simulation of Coupled Power and Gas Systems with Hydrogen-Enriched Natural Gas

Energies ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7680
Author(s):  
Yifei Lu ◽  
Thiemo Pesch ◽  
Andrea Benigni
Keyword(s):  
Natural Gas ◽  
Renewable Energy Sources ◽  
Simulation Method ◽  
Gas Pipeline ◽  
Electricity Sector ◽  
Electrical Network ◽  
Pipeline Network ◽  
Gas Network ◽  
Natural Gas Pipelines ◽  
The Impact

Due to the increasing share of renewable energy sources in the electrical network, the focus on decarbonization has extended into other energy sectors. The gas sector is of special interest because it can offer seasonal storage capacity and additional flexibility to the electricity sector. In this paper, we present a new simulation method designed for hydrogen-enriched natural gas network simulation. It can handle different gas compositions and is thus able to accurately analyze the impact of hydrogen injections into natural gas pipelines. After describing the newly defined simulation method, we demonstrate how the simulation tool can be used to analyze a hydrogen-enriched gas pipeline network. An exemplary co-simulation of coupled power and gas networks shows that hydrogen injections are severely constrained by the gas pipeline network, highlighting the importance and necessity of considering different gas compositions in the simulation.

Rainfall-Ground Movement Modeling for Natural Gas Pipelines Through Landslide Terrain

1996 ◽  
Author(s):  
G. D. O’Neil ◽  
G. R. Simmonds ◽  
D. A. Grivas ◽  
B. C. Schultz
Keyword(s):  
Natural Gas ◽  
Design Process ◽  
Threshold Value ◽  
Ground Movement ◽  
Ground Movements ◽  
Natural Gas Pipelines ◽  
Early Results ◽  
Current Design ◽  
Landslide Terrain ◽  
Rate Of Movement

Perhaps the greatest challenge to geotechnical engineers is to maintain the integrity of pipelines at river crossings where landslide terrain dominates the approach slopes. The current design process at NOVA Gas Transmission Ltd. (NGTL) has developed to the point where this impact can be reasonably estimated using in-house models of pipeline-soil interaction. To date, there has been no method to estimate ground movements within unexplored slopes at the outset of the design process. To address this problem, rainfall and slope instrumentation data have been processed to derive rainfall-ground movement relationships. Early results indicate that the ground movements exhibit two components: a steady, small rate of movement independent of the rainfall, and; increased rates over short periods of time following heavy amounts of rainfall. Evidence exists of a definite threshold value of rainfall which has to be exceeded before any incremental movement is induced. Additional evidence indicates a one-month lag between rainfall and ground movement. While these models are in the preliminary stage, results indicate a potential to estimate ground movements for both initial design and planned maintenance actions.

scholarly journals The Impact of Natural Gas Price Deregulation on the South Carolina Food-Processing Sectors

1983 ◽  
Vol 15 (2) ◽  
pp. 41-48 ◽  
Author(s):  
Mark S. Henry
Keyword(s):  
South Carolina ◽  
Natural Gas ◽  
Policy Debate ◽  
Natural Gas Pipelines ◽  
Natural Gas Markets ◽  
Natural Gas Prices ◽  
The Subject ◽  
Gas Price ◽  
The Impact ◽  
Recent Policy

The economic distortions that have been caused by federal regulation of natural gas markets have been the subject of many recent studies (Committee for Economic Development [CED]; Brickhill; Hall; MacAvoy and Pindyck; and Means). The most recent policy debate concerns the relative merits of alternatives to the price deregulation schedule of the 1978 Natural Gas Policy Act (NGPA). The range of options runs from freezing natural gas prices at current levels to complete decontrol of natural gas prices by January 1, 1986. Producers of natural gas, pipelines, distribution utilities, and end users all suffer from some sort of economic distortion under the NGPA (CED, pp. 50-60).

Hydrogen in Pipelines: Impact of Hydrogen Transport in Natural Gas Pipelines

2020 ◽  
Author(s):  
Rainer Kurz ◽  
Matt Lubomirsky ◽  
Francis Bainier
Keyword(s):  
Natural Gas ◽  
Gas Turbines ◽  
Supply And Demand ◽  
Operating Conditions ◽  
Pipeline System ◽  
Pure Hydrogen ◽  
Hydraulic Simulation ◽  
Natural Gas Pipelines ◽  
Natural Gas Pipeline ◽  
The Impact

Abstract The increased use of renewable energy has made the need to store electricity a central requirement. One of the concepts to address this need is to produce hydrogen from surplus electricity, and to use the existing natural gas pipeline system to transport the hydrogen. Generally, the hydrogen content in the pipeline flow would be below 20%, thus avoiding the problems of transporting and burning pure hydrogen. The natural gas – hydrogen mixtures have to be considered both from a gas transport and a gas storage perspective. In this study, the impact of various levels of hydrogen in a pipeline system are simulated. The pipeline hydraulic simulation will provide the necessary operating conditions for the gas compressors, and the gas turbines that drive these compressors. The result of the study addresses the impact on transportation efficiency in terms of energy consumption and the emission of green house gases. Further, necessary concepts in the capability to store gas to better balance supply and demand are discussed.

Condition-Based Optimal Maintenance Decision Modeling for Corroding Natural Gas Pipelines

2014 ◽  
Author(s):  
S. Zhang ◽  
W. Zhou ◽  
S. Kariyawasam ◽  
T. Huang
Keyword(s):  
Natural Gas ◽  
Probability Of Detection ◽  
Metal Loss ◽  
Gas Pipelines ◽  
Natural Gas Pipelines ◽  
Inspection Interval ◽  
Optimal Maintenance ◽  
Maintenance Decision ◽  
The Cost ◽  
The Impact

This paper investigates the optimal timing of the first inspection for newly-built onshore underground natural gas pipelines with respect to external metal-loss corrosion by considering the generation of corrosion defects over time and time-dependent growth of individual defects. The non-homogeneous Poisson process is used to model the generation of new defects and the homogeneous gamma process is used to model the growth of individual defects. A realistic maintenance strategy that is consistent with the industry practice and accounts for the probability of detection (PoD) and sizing errors of the inspection tool is incorporated in the investigation. Both the direct and indirect costs of failure are considered. A simulation-based approach is developed to numerically evaluate the expected cost rate at a given inspection interval. The optimal inspection interval is determined based on either the cost criterion or the safety criterion. An example gas pipeline is used to examine the impact of the cost of failure, PoD, and the excavation and repair criteria on the optimal inspection interval through parametric analyses. The results of investigation will assist engineers in making the optimal maintenance decision for corroding natural gas pipelines and facilitate the reliability-based corrosion management.

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