PAPER NUMBER

An Investigation Into How to Optimize the Effect of Drag Reducing Agents on the Flowrate and Pressure in Single Phase Fluid Pipelines
Ahmad Mamoun Naffa’a
Saudi Aramco

This paper investigates the optimization of the effect of drag reducing agents on the flowrate and pressure in single phase fluid pipelines. This presentation will discuss the investigations’ basis and approach, several studied factors, analysis of the results, recommendations, and effects on cost savings.

A Mathematical Approach to Optimization of Oil Flow Scheduling in Pipeline Systems
Alexander Losenkov,
Taras Yushchenko,
Svetlana Strelnikova,
Diana Michkova
Energoavtomatika

This paper considers a new approach to oil transportation scheduling in branched oil pipeline systems. This approach is based on a mathematical model that solves the linear and non-linear optimization transport problem. The presentation will discuss the problem of oil transportation and the mathematical approach to oil transportation scheduling. The possibilities of the proposed approach will also be provided.

Estimating Mixing Lengths in Multi-Product Pipelines
Guohua Li,
Hamid Bidmus
DNVGL

The paper revises the Austin-Palfrey equation to estimate the interfacial mixing length when the Reynolds number and/or the pipe diameter change along a pipeline, including takeoff and injection. The presentation will discuss the methods of the mixing length estimation, the mathematical derivations of the revised equation, the application of the revised equation, and three examples with hypothetical pipelines.

Evaluating Different Approaches for Tracking Batches in a Multi-Product Pipeline During the Presence of Slack
Giancarlo Milano
Atmos International

This paper compares an incompressible and empirical approach against a full model-based calculation of liquid pipeline behavior under the presence of slack for the purpose of accurately tracking batches in an online system and providing accurate Estimated Time of Arrival alarms to minimize product contamination.  During the presentation, side by side results of each approach will demonstrate the impact of each method driving to a final conclusion.

Innovative Terminal Pump Trip and Surge Relief Modelling
Utilizing History Matching and Equivalent Length Techniques

Bill Ma
Matus Hydraulics

Mary Goodreau, Susan Bachman
Enterprise Products

This paper discusses the use of an advanced simulation method for the worst-case terminal transient scenario (a mainline pump station trip along with a surge relief event) to successfully match the real surge pressure trend by arithmetically coding dynamic relief set points and converting all piping fittings into pseudo-piping with equivalent length to compensate for the pressure wave attenuation caused by piping fittings in real world operations. The presentation will discuss the simulation approach and its benefits.”

Adaptation of Fluid Motion Mathematical Model in Pipelines Using Drag Reducing Agents

Svetlana Strelnikova, Taras Yushchenko
Energoavtomatika

The paper discusses the question of mathematical model adjustment to characteristics of a certain pipeline focusing on the pipelines where DRA are used. The presentation will discuss actual problems of model adjustment and methods of using operational pipeline data for identifying DRA characteristics. The results of comparing modeling computations with real data from operating pipelines will be presented.

Understanding Economic Optimization of DRA in Crude Pipelines

Dennis Arensman
Enterprise Products

This paper will address a methodology of how DRA and power are optimized to minimize economic costs. An analysis will address how various parameters affect economic optimization results. Finally, this paper discusses several factors that affect decisions such as building new stations, laying new pipelines, or increasing DRA injection rates into existing assets. Results and key findings from these studies will be presented.

Transient Surge Pressures Due to Stagnant Heavy Oil in Cold Terminal Piping

Emma Perez
Enbridge Pipelines

This paper presents the transient simulation results of a relief system that contains different types of stagnant fluids in the piping to the relief tank. When a relief valve opens, the stagnant fluid requires a certain amount of pressure to be transported downstream, and the properties of the fluid inside the relief piping can make this flowing pressure higher than expected. Several cases are simulated to show the effect of stagnant heavy oil inside the relief piping and the response of this fluid when the relief system needs to operate.

Hydraulic Surge Studies for LNG Pipelines

Jonathan Burrows
DNV GL

This paper outlines the progression of LNG surge studies for a large and complex terminal. The presentation will discuss the evolution of the modelling with rationalization of the number of possible permutations; the development of simultaneous scenario modelling before such tools were commonplace; and the progression of this to include use of hydraulic results in pipe stress analysis to allow better operational understanding of the results. Closing with a brief look at the future of simultaneous modelling approaches.

A Mathematical Model for the Spatial Prediction and Time Evolution of the Column Separation in a Flowing Hydrocarbon Transmission Pipeline

Hamed Ghasvari Jahromi,
Fatemeh Ekram,
Michael Roxas,
Satya Mokamati
Vanmok Leak Detection Technologies Inc.

The paper discusses the phenomenon of column separation or slack line and the prediction of it at the point of inception in space as well as its evolution in space and time. Common causes of the event as well as some less common causes are discussed. Verification and validation of the novel mathematical model used for the predictions will be discussed. The robustness of the mathematical model-based computer algorithm will be demonstrated for the various causes of column separation such as lack of power, transient events in the pipeline, extended shut-in periods or leakage from the pipeline.

Insights to Turbomachinery Concerns in Pipeline Modelling

Matt Lubomirsky,
Roman Zamotorin,
Rainer Kurz
Solar Turbines Incorporated

This paper discusses different control methods to optimize the turbomachinery performance in compressor stations with multiple units. Different optimization methods are described.

Net Schedule Management as a Route to Dynamic Optimization

Balazs Rosta
FGSZ

Marko Haulis,
Ludek Reinstein
SIMONE Research Group

This paper discusses new approach to dynamically optimizing network mode for the near future (current day and the next day) in connection with predications of consumption, transit and ever changing nominations.

Hydraulic Modeling for Upstream Gas Production Planning and Allocation – Significance, Challenges, and Recommendations

Prasad Challa

Sapura Exploration and Production Inc

K.V. Rao
JNTUK

Jai Sahith,
Srinivasa Rao
UTP Malaysia

The paper highlights the challenges faced by the long and short-term gas planners while operating a large upstream gas network of pipelines along with measures to overcome these challenges. The presentation will discuss additional practices and hydraulic modeling techniques for enhanced integrated network operation. The offline simulation model will also be showcased highlighting the recommended features in the simulation environments for augmented user-friendliness.

Using Quality Tracking Data to Improve Billing Accuracy in a Complex Network

George Giannatos
Australian Energy Market Operator
Andy Bowe
DNV GL

This paper describes how quality tracking data from a dynamic real-time model has been used to enhance the process of billing end users in a pipeline network where diverse sources of gas and LNG are resulting in swings in quality of gas moving through the network. We will discuss the evolution of the design, the problems encountered during implementation, and the benefits (some of them unexpected) of the solution.

Optimization of Gas Transport – Evolutionary Calculations on a Small Cluster of Computers

Igor Mračka,
Tibor Žáčik,
Marek Hyčko,
Peter Somora,
Rudolf Hajossy
Mathematical Institute Slovak Academy of Sciences

 The purpose of the paper is to demonstrate the experience with distributed computing systems using evolutionary strategies for optimization problems in the gas industry. Two different approaches of distributed computing (star topology and cooperating agents) are presented.

CENAGAS’s Use of Pipeline Simulation to Support the New Infrastructure in the Mexican National Gas Pipeline System

Cesar Naranjo
CENAGAS

Paul Dickerson
Emerson

This paper will highlight some of the most important activities that were planned based on pipeline simulation techniques to establish new projects to increase transport capacity. This includes new compression stations and reconfiguration of existing compression stations. The presentation will discuss and verify the parameters and assumptions that CENAGAS has implemented and incorporated into the pipeline simulation of the new short-term agreements.

Pipeline Transient Optimization for a Gas-Electric Coordination Decision Support System

Anatoly Zlotnik, Kaarthik Sundar
Los Alamos National Laboratory

Alexandr M. Rudkevich
Newton Energy Group
Richard Tabors, Xindi Li
Tabors Caramanis Rudkevich

Transient optimization of gas pipelines has experienced a resurgence of interest inspired by the need to coordinate wholesale electricity and natural gas transmission networks.  Comprehensive modeling of pipeline components and network topologies; scalability, speed, and accuracy of computations; and data assimilation of state estimates and forecasts in industrial systems present ongoing challenges.  This talk will describe the use of optimization formulations for electricity and gas networks as economically and operationally efficient intra-day coordination mechanisms and highlight research and development needs required to field a future transient optimization-based decision support system for midstream gas transportation.

Implementing a Real Time System Where a Majority of Deliveries are not on SCADA

Samon Kashani
Gregg Engineering

Alisa C. Bullard
New Mexico Gas Company

In this paper we combined the use of a hydraulic simulator, load prediction software, and data analysis to develop a methodology to simulate the transient behavior for several large off-SCADA deliveries. A transient Real Time Model (RTM) was built utilizing both actual SCADA data and simulated SCADA to accurately model the system. This model demonstrates that it is feasible to model the system in an RTM even though there is missing SCADA data.

Gas Condensation and Phase Diagram in Multiphase Flow Systems

Ullas Pathak
Aaron West
Statistics & Control

A study conducted on real-time pipeline production systems for detection of phase changes to reduce incurred losses is presented. The model allows for the dynamic monitoring of gas condensation in multi-phase pipeline through temperature, pressure, composition and other thermodynamic state variations. Higher pressures in these systems can lead to condensation and hold-up, which can produce excessive costs from both downtime and repairs. To validate the model, the solution was implemented and studied on an industrial scenario for gas transmission pipelines with varying compositions, and the phase compositions were calculated via multi-parameter equation-of-state and solution of the Rachford-Rice equation. Based on the phase composition and the dynamic PT-diagram, gas condensation detection and monitoring are provided.

PG&E’s In-Line Inspection Process from Start to Finish

Kim Rafter,
Jen Cellucci
Pacific Gas and Electric Co.

This paper will provide an overview of PG&E’s In-Line Inspection process from start to finish including feasibility studies and in-line inspection operating methods. It will also cover the hydraulic analysis and tools used to simulate operating conditions and assess system impact due to anomalies and repairs.

Step Doubling for Pipeline Flow

Todd F. Dupont
The University of Chicago

Richard Myers
DNVGL

This paper defines and studies Affine Step Doubling with Local Extrapolation–a simple, efficient method for discretizing pipeline equations in time.  The properties of the method are illustrated with analysis on a simple scalar ordinary differential equation.  Improved time stepping behavior will then be demonstrated with examples based on pipeline operation.  This method is second order correct in time and is suitable for adaptive time stepping.

Guided, Accelerated Parametric Studies

Richard G Carter,
Andrew Daniels
DNV GL

Jonathan Fasullo
TransCanada

John Korta,
Bill Hirsch,
Richard Jennings,
Newton Chou
PG&E

Engineers often study system behavior by running a collection of simulations while varying selected parameters over a mesh of values. This simple powerful technique can lead to improvements in system design and operation but can be time consuming and computationally expensive.  We present a method for accelerating parametric studies so that desired information can be uncovered more quickly, and larger studies can be performed than would otherwise not be possible. We illustrate this method with real examples from pipeline operations.

Probabilistic Analysis of PHMSA Data for Pipeline Spill Risk Analysis

Philip Carpenter
Great Sky River Enterprises

Morgan Henrie
MH Consulting

Yoshihiro Okamoto II, Paul Liddell
Alyeska Pipeline

Our paper describes a statistical evaluation of U.S. Department of Transportation (DOT) Pipeline and Hazardous Materials Safety Administration (PHMSA) incident data to support pipeline spill risk analysis. We derive useful stochastic predictive relationships using the publicly available information in the PHMSA database, and then present methods to adapt the data to a specific pipeline when only sparse incident data is available for the target system. A simplified Monte-Carlo spill risk simulation methodology using this information is also discussed.

Absolute Roughness of Pipes from Different Manufacturing and Treatment Methods and Impact on Pipeline Design

Hamid Bidmus
DNV GL

James Chau
Fluor Canada Ltd

Kenton Dechant
Bri-Steel Manufacturing

This study measured the absolute roughness of various pipeline samples obtained from commercial steel pipes manufactured with various methods including: seamless hot-rolling, cold-drawing, cold pilgering, hot expanding, and welded HFIW and DSAW processes. The recorded average pipe roughness values ranged from about 50 micro-inch for stainless steel pipe to 1034 micro-inch for heat treated carbon steel pipe. Results are also presented showing the impact of applying the different absolute roughness values to case studies involving multiple crude oil pipelines and a natural gas pipeline.

An Evaluation of Negative Pressure Wave Leak Detection: Challenges, Limitations, and Use Cases

Joe Reynolds,
Amy Kam
AVEVA Software, LLC

This paper discusses Negative Pressure Wave (NPW) leak detection and highlights the challenges faced when implementing it as well as some of its strengths and weaknesses. The presentation will discuss the theory behind NPW leak detection and analyze the results from a NPW solution that was evaluated on two different liquid pipelines running offline simulators.

Operational Risk Management for Oil/Condensate Pipeline Systems

Elin Kristin Dale-Carr,
John Ivar Lokna,
Lars Hagesaether
Equinor ASA

This paper discusses how different assumptions and parameters used in pipeline risk assessments affect the estimation of risk level for oil/condensate pipeline systems in operation. The presentation will discuss how knowledge of risk calculations, pipeline simulations and assumptions are a prerequisite to strengthen the risk management decision basis for the operator. Examples of best practice for use of data, methods and simulations will be included.

Leak Detection Experiences in the Antipodes

Peter Smit
Refining NZ

Neil Stockton
Emerson

This paper describes practical experience of Real-Time Transient Model based leak detection on a 169 kilometre (105 mile) long, 273 millimetre (10.75 inch) diameter pipeline, transporting multiple liquid products on New Zealand’s North Island. The leak detection methodology is discussed in the presentation, alongside a timeline of a real pipeline incident and associated response.

Pipeline Performance Data Analysis through Machine Learning with Hydraulics Model Assisted Training

David Cheng, Daniel Zeosky
Fluor Enterprises, Inc.

This paper discusses a new method to gather and analyze pipeline flow conditions directly from data fed through machine learning as opposed to through modeling. This will lead to increased accuracy of flow conditions throughout the life cycle of a pipeline. The presentation will discuss how this data will be gathered and applied to our model in order to demonstrate this increased accuracy.

Improving Leak Detection System Performance with
Non-Intrusive Sensors

Andrew Hoffman,
Harry Smith,
Jun Zhang
Atmos International

The performance of pipeline leak detection systems has been a hot subject for discussions in the past few years. To improve the leak detection performance of CPM (Computational Pipeline Monitoring) systems, non-intrusive sensors have been developed. This paper will discuss a few application examples of the non-intrusive sensors on both multi-phase and multi-product pipelines.

Computing Crude Oil Specific Gravity, Bulk Moduli, and Cp/Cv from Speed of Sound Measurements

Ed Nicholas
Nicholas Simulation Services

Norense Okungbowa
Enbridge Pipelines

Ultrasonic flow meters, in addition to calculating flow rate, measure the speed of sound in the fluid at the local fluid pressure and temperature.   It is desirable to be able to compute the crude oil specific gravity at base conditions from this measurement.  However, there is no straightforward way to do this.  The authors propose a calculation approach and compare the results with those obtained from densitometers.

Investigation on Parameters Affecting the Performance of Negative Pressure Wave Leak Detection Systems

Mingang Jin
Emerson Automation Solutions

This paper investigates the parameters affecting the uncertainty of the leak location inferred by Negative Pressure Wave (NPW) leak detection systems and discusses the appropriate definition of the minimum detectable leak size for NPW systems. The presentation will discuss the NPW methodology, numerical tests and findings of this investigation.

PAPER NUMBER

A Comprehensive Model for Predicting Efficiency of DRA
in Liquid Pipelines
Wei Zeng
WPH Engineering Ltd.
Xihua Min, Shujuan Qiu
PetroChina West Pipeline Company

This paper discusses a mathematical model for predicting efficiency of DRA in liquid pipelines that correlates drag
reduction as a function of pipe diameter, fluid viscosity, DRA type and  concentration, and Reynolds number, so as to apply to a variety of pipelines and a wide range of fluid properties. The presentation will discuss the approaches of processing field test data and developing a comprehensive model. Results of model predictions vs the actuals will also be provided.

Real-Time Sand Deposition Prediction in Multiphase Flow
John Hooker, Daniel Theis
Statistics & Control, Inc.

Sand management technology has become more prevalent in the petroleum industry to increase well production. This paper and presentation explores the multiphase model and computational algorithms used to simulate multiphase flow with sand particles through a subsea pipeline to predict the pressure gradient, transport velocity, and sand deposition.

Modelling of Rapid Transients in Natural Gas Pipelines
Fábio Capelassi,Gavazzi de Marco, Sergio Lacerda
TBG
Garry Hanmer, Victor Mora
Atmos International

This paper discusses the modelling of rapid transients in natural gas pipelines caused by the sudden shutdown of compressors, or the abrupt changes in flow rate due to leakages. The  presentation will discuss the  mathematical models capable of modelling the detailed rarefaction wave of these rapid transients.

Pipeline Model’s Level Profile: Optimizing the Selection of
Sample Points
Rafael Noguerol
Emerson

The paper presents an algorithm for the selection of level profile points for leak detection modeling purposes. It is
intended for downsizing a large number of elevation samples (tens/hundreds of thousand points…) into a reduced number of representative samples. Some indicators are built in order
to evaluate the goodness of the results. A less computationally intensive method is derived for even larger original samples. The algorithms can be applied for any set of data, not only level profiles.

Modeling of Heavy Crude

James Yang, John Dawson, Karen Jia
Access Pipeline

This paper presents specialized simulation techniques addressing some of the unique challenges related to
simulation modeling of heavy crude (dilbit) pipeline systems. These techniques were developed to improve the accuracy and effectiveness of modeling efforts associated with
simulation of seasonal operation, and product blending and include methods to modify fluid properties with simulation coding. 

Reinforcement Learning in Gas Transport Control

Tibor Žáčik, Igor Mračka, Marek Hyčko,
Rudolf Hajossy
Slovak Academy of Sciences

The purpose of the paper is to show how reinforcement learning approaches can solve some problems of a gas transport control in transient conditions. An agent (controller) learns to sequentially operate a compressor station to be able to make autonomous decisions.

A Slack Flow Model With Moving Regime Boundaries

Jason Modisette
Atmos International, Inc.

This paper presents a new two-fluid model for slack flow in liquid pipelines. This model allows the downstream end of the slack region to move in a continuous manner, rather than forcing it to jump discontinuously from one spatial mesh point to the next like existing slack models. The advantages and disadvantages of the method will be discussed, and the model results will be compared with data for slack in real
pipelines.

Effect of Placing a Relief System outside the Flow Path in a Crude Oil Pipeline System

Hamid Bidmus
Fluor

This paper discusses the mitigation of overpressure in a pipeline system using a relief system that is not connected to
the pipeline along the path of the flowing crude oil. Closure of a valve at the end of the pipeline system is responsible for the overpressure being mitigated. The presentation will discuss
how this configuration affects the maximum transient pressures observed and the impact of varying the valve
closing times.

Performance Testing Data Interpretation Using Markov Chain Monte Carlo Methods for a Natural Gas Transmission Pipeline with Compressor Station

David Cheng
Fluor
Mario Arredondo Arce
Kiewit

A Markov Chain Monte Carlo (MCMC) method is introduced to find pipeline parameters that enable the best match to the performance testing data. An actual long distance gas pipeline
performance test result is presented to demonstrate the method. Instead of identifying a single parameter such as
pipeline roughness the proposed method helps to provide estimates of multiple parameters based on the data. The influence of black powder on gas pipeline pressure loss is included in the model. The results show better matching
between the measurement data and hydraulics model prediction because of the consideration of more physical
aspects.

Optimization of Gas Networks Under Transient
Conditions

Andrzej J. Osiadacz, Maciej Chaczykowski
Warsaw University of
Technology

This paper discusses the problem of transient optimization of gas transmission networks. The  optimization algorithm for a
network of arbitrary structure with the objective being to minimize the fuel consumption of the compressor stations is investigated. The predictions from the numerical solution have been verified on the telemetry data of a large-scale gas
network. 

Mitigation of Slugging Phenomena in Offshore Oil Export
Lines

Ivor Ellul
CiSK Ventures, Ltd
Mike Zaldivar
Evoleap
Kyle McLawhon
EDG Consulting Engineers

The results of a study are presented that addresses the issue of slugging in an export oil line to a FPSO vessel. Slugging is caused by the spiking of gas into the oil line intended to serve as fuel gas on the FPSO. The system is modeled with the insertion of a slug control valve and an operating procedure developed that will mitigate slugging in the line.

Operational Experience With Introduction of a Light Fluid Into a Heavy Oil Pipeline System

Arild Stokkenes, Svein Bjarte Joramo,
Hustvedt Arve Vestbø
Statoil

This paper will discuss the changes for operations with introduction of a light crude to an offshore heavy oil pipeline network. The presentation will cover wax control with focus on pigging design, wax deposition and how to effectively follow up the selected control strategy. It will also discuss
laminar flow regime that has been an unexpected outcome when mixing two turbulent flows at a wye.

Centrifugal Compressors Transient Surge Analysis: When Do You Need a Hot Gas Bypass Line?

Augusto GarciaHernandez, Adrian Alvarado

Southwest Research Institute

This paper presents a general approach for conducting centrifugal compressor dynamic modeling and the considerations that should be taken when designing a recycle loop with or without a hot gas bypass. In addition, case studies are presented to illustrate how to possibly avoid hot gas bypasses while increasing the effectiveness of the antisurge system.

Evaluation of New Approach to Testing Performance of a Pipeline Leak Detection System

Philip Carpenter
Great Sky River Enterprises LLC
Daniel Hung
Enbridge Pipelines Inc
Ed Nicholas
Nicholas Simulation Services LLC

We follow up on our previous paper describing a softwarebased, leak-perturbation signature API RP 1130 compliant test method by providing a rigorous analysis and testing of the hydraulic limitations of the method, and benchmarking it against other commonly employed leak testing approaches. The work continues to demonstrate that previous conclusions regarding its relatively low cost, high hydraulic fidelity, coverage, and flexibility are maintained, while producing extensive output metrics that include detailed leak detection
sensitivity maps, false alarm rates, and supporting statistical analysis.

Propagation of Telemetry Data Error in Simulation Calculations

Maciej Szeniawski, Stanisław Brzęczkowski
GAZ-SYSTEM S.A.

This paper addresses situations where invalid SCADA data causes disturbances of simulation model calculations. The paper also presents affects when receiving incorrect data for nonlinear elements as well as for input or output points. Examples are presented showing how these situations may be dealt with, and what possible settings should be included in SCADA systems to eliminate such cases or limit their impact.

Long-haul Natural Gas Pipeline Compressor Station Optimization

Vadim Shapiro, John Hooker, Lawrence Youngblood
Statistics & Control,
Inc.

This paper introduces a unique method to simulate and optimize complex natural gas transmission systems with multiple compressor stations and pipelines. Technological advances include a new parsing engine, advanced regulatory control, and incorporating turbomachinery algorithms for mixed mode operations. The presentation will discusses these advances and present the field-validated results.

Modeling and Mitigation of Acoustic Induced Vibration (AIV) in Piping Systems

Brandon Ridens, Sarah Simons, Tim Allison, Klaus Brun
Southwest Research
Institute

This paper explores new mitigation concepts and analysis techniques developed to extend the current state of the art acoustic induced vibrations (AIV) analyses. These new methods are intended to more accurately solve AIV problems found in blowdown and piping systems. The test set-up, instrumentation, and results; computer modeling, and conceptual solutions will be discussed in detail.

Tips and Tricks for Accurately Modeling Pumps

Mary Goodreau, Dennis Arensman
Enterprise Products

Most of the time pump curve approximations used by pump vendors and within modeling software are reasonably accurate for hydrocarbon liquids. This paper describes conditions where results from approximated pump curves and calculations need to be scrutinized. Solutions to deal with
inaccurate pump curve approximations or calculations are presented.

PAPER NUMBER

Forecasting of Gas Quality
Stanislaw Brzeczkowski, Maciej Szeniawsk
GAZ-SYSTEM S.A.

Knowledge of natural gas quality (in the short-term future) is expected by many of end users. There are sources where gas composition smoothly changes in function of time or depends on flows. The dynamic simulation with full quality tracking model of the multi-loop transmission network allows such information to be provided.

Computing Natural Gas Losses From Damaged Pipelines Using Analytical Discharge Equations and Network Modeling Software
Hugo A. Lecuyer
Gaz Metro LP
Corey Rice
DNV GL

This paper reviews the analytical equations available to compute discharged volume during third party digging damages on natural gas distribution systems. A methodology is also described to obtain an accurate estimate of the system upstream pressure using CFD software for both sonic and sub-sonic flow regimes. Results produced by the methods are also compared to field and laboratory data.

Localization of Gas Pipeline Rupture Using a Massive Parallelization on GPGPU
Igor Mračka, Rudolf Hajossy, Tibor Žáčik
Slovak Academy of Sciences Bratislava
Peter Somora
Altova GmbH

The article deals with a rupture localization system based on massive parallelized simulations on GPGPU. The main advantage of this approach is that it combines highly precise simulation of gas flow (to achieve localization accuracy) and a massive parallelization (to obtain sufficient calculation speed). This approach has been tested using simulated scenarios and data from real ruptures.

A Method for Calibrating Parallel Pipes Without Inline Flow Measurement
Michael Dew
Michael Dew Consulting, LLC

This paper will describe a method for using multiple SCADA data sets to calibrate the efficiencies of parallel pipes that lack individual flow measurement by plotting the possible solutions of each data set to determine their point of intersection. The presentation will demonstrate this methodology on a theoretical pipeline subsystem to illustrate the manner by which it could be applied to real systems

Using Pipeline Simulator To Model High-Speed Dynamic Events on
a Microsecond Scale

Vit Meistr, Marko Haulis
SIMONE Research Group

This paper discusses modeling of events on a millisecond scale using standard 1D simulation software. It outlines the pitfalls and recommendations and shows how to achieve such a time discretization. It also provides some examples where these calculations may be beneficial

Modeling of Critical Transient Events in Piping Systems

Augusto Garcia-Hernandez, Adrian Alvarado
Southwest Research Institute

New designs or modifications of existing pump or gathering facilities are required frequently in many industries due to new operating conditions, increases in product demand, issues with pump-pipeline interaction, pulsation problems, Net Positive Suction Head (NPSH) requirements, etc. In many cases, harsh transient events such as slugs, water hammer, and cavitation that can create high amplitude forces; pressure spikes can often result in high impact forces, and vibrations can sometimes result in failures. This paper presents a general approach for modeling critical transient events in liquid and multiphase piping systems.

Impact of Pipeline Pressure Surge on Seawater Treatment for Injection

Xuesong Wang, John D. Yurchevich
Amec Foster Wheeler

This paper presents a novel method that has been developed to simulate an energy recovery system, and to estimate maximum surge pressure and pressure rise rate. The presentation will discuss the energy recovery system model, integration with existing pipeline models, and surge analysis results. The method sheds light on simulating energy recovery system and can be adopted by different simulation tools.

Accurate and Efficient Methods for Turbo-Compressor Fuel Consumption Calculations

Matt Lubomirsky, Rainer Kurz
Solar Turbines

This paper presents the results of a study conducted for compressor stations where two different methods were used to improve the accuracy of compressor station fuel calculation from 2-3% down to around 0.25%. The first method relates to elevation correction and it uses engine data files that contain the fuel consumption data for sea level only. The second method is a “Power Turbine Off-Optimum Speed” iteration process where the actual fuel consumption value is found using iterations between power turbine optimum power and speed until the target value is found.

Installed Control Valve Characteristics and Its Influence on Surge
Pressure in Piping Design

David Cheng, Roberto Portillo
Fluor Enterprises, Inc

This paper examines how the connections of the control valve with other piping components can influence the installed valve characteristics and the surge pressure level. Valve characteristics have a big influence on surge pressures for liquid systems. The combination of the control valve with other components may introduce undesirable surge pressures during operations which are commonly neglected while designing the system.

Compressor Fuel Minimization Under Transient Conditions

Andrzej J. Osiadacz, Maciej Chaczykowski
Warsaw University of Technology

This paper discusses the problem of optimal control of a natural gas transmission system consisting of a compressor station and adjacent pipeline sections. The presentation will discuss an algorithm of automatic search for the optimal values of the operating parameters of the compressor station.

Fractional Factorial Analysis of Parameters Affecting Leak Detection Model Transient Resolution

Shawn Learn, Ryan Dolan
TransCanada Pipelines

This paper examines the results of an API 1149 (2015) leak detection sensitivity analysis for a simple liquid pipeline. The study uses an n-1 factorial design to quantify effects of the simulation parameters as well as the confounding factors. The analysis examines several simulation parameters and the paper discusses the application of this method to simplify future leak detection system analysis.

Simulation Based Performance Test of a Natural Gas Transmission
Pipeline With Compressor Station

David Cheng, Mario Arredondo Arce,
Roberto Portillo
Fluor Enterprises, Inc.

This paper discusses how performance tests can be validated for operating conditions that differ from the design conditions by evaluating the fundamental physical parameters. Pipelines are normally designed to achieve certain flow rates during different phases. However, it is not uncommon to see pipelines falling short on gas supply during the time period that the performance test is scheduled for. The paper will present the performance test results of a long distance gas pipeline to show how the method was implemented.

Importance of Pipeline Roughness in Greenfield and Expansion Projects

Dennis Arensman

Enterprise Products

This paper shows that the tuning parameter of pipeline roughness varies based on the product flowing within the pipeline. Examples within the paper will show the financial impact of using the standard value of 0.0018 inch for pipeline roughness versus a more accurate prediction value based on the product flowing within the pipeline. The presentation will discuss the approach used to verify how pipeline roughness changes based on the product within the pipeline. It will also show examples proving the importance of a more accurate prediction value.

Real-Time Congealing and Pipeline Monitoring System

Ullas Pathak, Daniel P. Theis, John Hooker
Statistics & Controls, Inc

This paper discusses how models are built using scientific principles and how simulation may be used to predict where congealing is or may occur inside a pipeline. The presentation will discuss the scientific foundation and mathematical approach and will provide a case study using these modeling and simulation techniques.

Economic Optimization of Intra-Day Gas Pipeline Flow Schedules
Using Transient Flow Models

Anatoly Zlotnik, Scott Backhaus
Los Alamos National Laboratory
Alex Rudkevich, John Goldis
Newton Energy Group
Pablo Ruiz, Michael Caramanis
Boston University
Richard Carter
DNV-GL
Richard Tabors, Richard Hornby
Tabors Caramanis Rudkevich
John Rosenkranz
North Side Energy
Daniel Baldwin
Kinder Morgan

Growing dependence on gas-fired power generation requires better coordination of wholesale natural gas markets with electricity markets, in which prices consistent with power grid physics are obtained by economic optimization. Similar optimization using transient pipeline models would provide location and time dependent intra-day gas prices consistent with pipeline physics. Gas-electric coordination is envisioned as organized exchange of hourly burn schedules and gas prices obtained by pipeline market optimization that accounts for transient flows, compressor constraints, and pre-existing contracts.

Local Distribution Zone Operational Management Tools

Jon Barley
Emerson

Glen McGowan
SGN

Balancing the need to meet daily demand whilst operating within designed limits, as well as adhering to strict rules and procedures governing hourly intake rates, requires careful management by UK Local Distribution Zone (LDZ) operators. This paper discusses operational tools developed to assist in the day-to-day management of the gas pipeline networks.

Gas System Intelligence – Uncovering Critical Regulator Stations in
Embedded Multiple Pressure Distribution Networks

Eban Mustapha Hamdani
Pacific Gas & Electric

This paper utilizes advanced pipeline simulation software to proactively identify and rank critical distribution regulator stations to meet customer demand. A complex distribution network in a single model containing embedded systems at multiple operating pressures is analyzed over a large number of scenarios using PG&E’s Batch Analysis Tool (BAT). The presentation will discuss interconnected hydraulically independent systems in a distribution model, critical regulator analysis and utilizing the BAT to identify critical regulator stations. A brief overview of the BAT setup and results will also be provided.

A New Approach To Testing the Performance of a Pipeline Leak
Detection System

Ed Nicholas
Nicholas Simulation Services
Philip Carpenter
Great Sky River Enterprises LLC
Morgan Henrie
MH Consulting, Inc.

Daniel Hung, Kris Kundert
Enbridge Pipeline

Testing of pipeline leak detection systems is difficult to do well. It is also a critical activity which provides key information on the systems capability for communications to regulators and key stakeholders. The authors describe an API RP 1130 compliant test method that relies on the development of a limited number of realistic “leak signatures” that are superimposed on archived SCADA data in a way that preserves not only a faithful representation of the leak, but the real-world impacts of noise, calculation uncertainties, and measurement errors as well. In addition to maintaining high hydraulic fidelity, coverage and flexibility, this procedure is performed at low cost while potentially providing a greater degree of insight into the detailed performance of the leak detection system than can be achieved with other methods.

Hydraulic Analysis to Support Large Scale Pipeline Outages Using
Portable Natural Gas

Colleen Barrera, Molly Richard, Bill Bishop, Miguel Macias
Pacific Gas & Electric

This paper describes the hydraulic analysis completed in support of significant pipeline outages required to perform safety and integrity work in the California cities of Santa Cruz and Redding. The presentation will discuss the tools, processes, and equipment used throughout the planning and execution phases of the outages.

PAPER NUMBER

Leak Detectability in an Off-shore Multiphase Production System
Augusto Garcia-Hernandez, Jeffrey Bennett
Southwest Research Institute

This paper and presentation will discuss the results of a multiphase study of a 30-inch off-shore pipeline system under steady state, slugging conditions, and transient leak conditions. In addition, a sensitivity analysis of different gas oil ratios is presented as well to map out its effect on the leak detectability.

Analysis of Depressurization of Onshore Pipeline Containing Flashing Liquid
Alessandro Terenzi, Enrico Bonato, Lorenzo Maggiore
Saipem S.p.A.

The paper presents a study on onshore pipeline depressuring behaviour of flashing liquids, based on the sensitivity on main physical governing parameters by considering realistic configurations and operating conditions. The presentation will present and discuss the impact on the operation of fluid thermodynamic properties, heat transfer from the environment, pipe wall thickness, pipeline elevation profile, discharge rates and discharge location configuration.

Flow Assurance – at What Cost?
Mack Shippen, William Bailey
Schlumberger, Ltd.
Ivor Ellul
CiSK Ventures, Ltd

The paper aims to identify the critical design factors for the pipeline and associated process equipment that most influence the overall performance of the system with an objective to increase the confidence in our go-to-purchase decisions. A practical decision making procedure is presented that considers both multiphase flowbased aspects (key design alternatives) as well as infrastructure cost, manufacturing lead time, commodity price (key economic drivers). Examples are examined where rigorous pipeline simulation analysis drives the design of the systems under consideration. A process workflow is presented detailing the approach to the sizing of such system components as the pipeline, flowline, separator, and slug catcher.

Modelling and Simulation of Gassco Wet Gas Pipelines
Ola Johan Rinde
Gassco AS
Garry Hanmer, Dr. David Basnett, Fayaz Issak
Atmos International, UK

This paper addresses the application of a single phase simulation software to Gassco’s wet gas pipelines. To meet their on-line pipeline modelling and simulation requirements Gassco carried out a thorough review of both multi-phase and single-phase simulation software solutions in the market. To help with their evaluations, a single-phase software was configured and implemented on three wet gas networks. The simulation results were surprisingly close to actual measured flow and pressure values. To provide liquid build up estimations, an additional module has been developed. With this enhancement accurate gas and liquid calculations have become possible for on-line and offline simulations.

Applying the Simulated Annealing algorithm to Optimize the Scheduling of Products Pipelines

Haihong Chen, Changchun Wu, Lili Zuo, Wang Li, Yang Yu
China University Petroleum, Beijing, China

This paper discusses an optimization program that minimizes flow rate fluctuations of pipe segments changing with time during the scheduling horizon by optimizing delivering scheduling plans of a single source and multi-terminals products pipeline. The presentation will discuss how to solve the model by the Simulated Annealing algorithm. A case study on a read world products pipeline called LC will also be provided.

Modeling Heavy Crudes

Mary Goodreau
Enterprise Products

Modeling heavy crudes is not as straight forward as modeling other crude oils. Even though an oil may be Newtonian, it may act like a non-Newtonian fluid in cold temperatures and low flow conditions. There are many systems which may not require modeling for lighter oils which can be a significant issue with heavy crudes such as relief systems or piping between tanks and booster pumps. This paper will provide insight into these modeling issues and tips on avoiding some of the pit falls.

From Pipelines to Manifolds: Practical Considerations for
Modeling Liquid Systems

Jeffrey Bennett, Augusto Garcia-Hernandez, Adrian Alvarado
Southwest Research Institute

This paper and presentation will discuss the application of pipeline simulation tools to systems ranging in size and scale. Representing system pressure drops, tuning models to field data, simplifying complex networks plus selecting equations of state and heat transfer modes will be discussed.

An Integrated Simulation Tool for Analyzing the Operation and Interdependency of Natural Gas and Electric Power Systems

Kwabena Addo Pambour, Gerard P.J. Dijkema
University of Groningen
Burcin Cakir Erdener, Ricardo Bolado-Lavin
European Commission, JRC

This paper presents an integrated simulation tool for analyzing the interdependency of gas and electric power systems in terms of security of energy supply. The presentation will discuss the mathematical approach for modeling the key facilities in both systems, their physical interconnections and the implementation of the integrated model into a simulation tool. A demo of the developed tool will be provided.

Elasticity Model for Joint Gas-Grid Expansion Planning Optimization

Conrado Borraz-Sanchez, Russell Bent
Los Alamos National Laboratory
Pascal van Hentenryck
University of Michigan
Seth Blumsack
Pennsylvania State University
Hassan Hijazi
Australian National University

Despite the dependencies between natural gas and power systems, their respective industries have technical, political and commercial constraints that often force them to plan, operate and manage in isolation. Consequently, undesirable outcomes may arise such as those experienced by both systems during the winter of 2013/2014 in the northeastern United States. In this paper, we describe our previous work in convex relaxations of a Combined Electricity and Gas Expansion (CEGE) planning model, and introduce a gas-price elasticity model to analyze the effects of gas-price volatility caused by congestion of the CEGE system. We also tested greedy heuristics, which proved to be computational and numerical challenging. Contrary to successful heuristics that are able to evaluate candidate solutions quickly (milliseconds), evaluations of CEGE candidate solutions take seconds. Numerical instabilities are also exhibited when applying conic solvers. To overcome these limitations, we are
evaluating a hierarchical approach based on faster elaxations, and cutting plane algorithms to replace the conic constraints. We expect this will significantly improve the proposed heuristic approaches.

Impact of Regulatory Change to Coordinate Gas Pipelines and Power Systems

Richard Carter, Andrew Daniels, Alex Hollis
DNV-GL
Antoly Zlotnik, Scott Backhaus, Michael Chertkov
Los Alamos National Laboratory
Anthony Giacomoni
ISO New England

Recent trends have strengthened the interdependence between the electric power and natural gas industries. Particularly problematic are intra-day fluctuations in pipeline loads arising from large changes in gas-fired electric power plant operation. To give pipeline operators better insight into these loads, we will give a short tutorial on the power-plant generator commitment procedure used by balancing authorities to decide when and where generators are activated. We will also discuss recent FERC regulatory changes for improving operational coordination between the two industries.

Using Power Grid Schedules in Dynamic Optimization of Gas Pipelines

Anatoly Zlotnik, Michael Chertkov,
Scott Backhaus
Los Alamos National Laboratory
Richard Carter, Alex Hollis, Andrew Daniels
DNV-GL

Gas-fired power plant commitment and dispatch schedules can
provide a forecast of high and variable gas takes by power plants. Thus, transient optimization can enable natural gas systems to interoperate with electric power systems on the time-scale of power production changes to mitigate intra-day interdependence issues. We will describe recent methods for rapidly solving transient optimization problems of intra-day flow scheduling and compressor operation for large-scale pipeline systems. We will demonstrate and quantify the efficiency and security advantages of using these techniques to exploit available inter-industry communications.

Pipeline Simulation Modeling Advancements – Numerous Scenarios Analyzed Simultaneously

Rick Brown
Pacific Gas and Electric

Nancy Gilmore
GTS Engineering & Consulting

This paper will discuss and demonstrate technology developed by PG&E and GTS to address the unprecedented increase in safety work occurring at PG&E. The new technology, called Batch Analysis Tool (BAT) enables the planning engineer to analyze systems under a multitude of demand and operating conditions as a “batch” of simulations. User-defined scenarios are performed and cataloged in an automated, sequential manner rather than manually, one run at a time. This approach allows for the performance of hundreds or thousands of scenarios accurately and rapidly. This process also aids in optimizing operations and uncovering non-intuitive solutions. The benefit of this technology extends beyond companies with large amounts of safety work to include any study that requires a range of inputs to be hydraulically analyzed. Business justification and strategic technology are the primary emphases of this presentation. Representative use cases of the new technology will be presented by PG&E in supplemental papers.

Batch Analysis Tool Use Case – Operational Impact of Safety Work on PG&E’s Peninsula Local Transmission System

Newton Chou, Stewart Lee, Rick Brown

Pacific Gas and Electric

This paper discusses the operational impact of safety work on PG&E’s Peninsula Local Transmission System and the use of PG&E’s Batch Analysis Tool to simulate hundreds to thousands of scenarios associated with numerous pipeline outage possibilities and a wide range of system operating scenarios at different temperatures/demands. The paper will provide a practical use case of BAT to illustrate how it makes rapid and thorough hydraulic analysis for a large number of scenarios feasible and provides system intelligence and system optimization.

Batch Analyses Tool – Distribution System Use Cases

Ben Kolnowski, Elisha Ezersky
Pacific Gas and Electric

This paper presents actual use cases of PG&E’s Batch Analysis Tool to analyze a multitude of scenarios on natural gas distribution systems. Various use cases involving operation optimization and system monitoring and performance will be explained in detail, demonstrating significant gains in system intelligence and analyses efficiency.

Multi-Parameter Residential Hourly Profile Models Using AMI Hourly Customer Gas Usage Data

Jim Maguda
Pacific Gas and Electric

 The installation of Advanced Metering Infrastructure (AMI) at PG&E has created the opportunity to evaluate the usage patterns of gas customers. This presentation and paper highlights the challenges in gathering and data mining this voluminous usage data and the corresponding development of mathematical models to forecast 24- hour usage profiles of residential customers through the use of multilinear regression analysis.

The Next Dimension of Flow Profiles

Steve Edwardson
Union Gas Limited

This paper will discuss the steps used in creating a typical two-dimensional regular-rate normalized flow profile. It will also introduce the concept of “deskewing” the data and adding
temperature as a third-dimension to allow the profile data to be extrapolated out to a design day and be characterized in a 3D surface graph.

Single Phase Gas Transmission Modeling With Limited Usage Data

Wahyu Dwiagasta
Wibowo, Hendry Pramudibta S., Dea Amelia, Karisnda Rahmadani, M. Fikrie Farhan, M. Haryo Pramantyo
PT. Perusahaan Gas Negara (Persero) Tbk.

This study is focused on loading transient single phase gas
transmission pipeline simulation methods with limited usage data by using MS Excel. The presentation will discuss the mathematical approach, case study within PGN gas transmission pipeline scope, other features such as gas composition & parameter tracking, and future development. We will provide a demo of the calculation methods

Quadripole Models for simulation and leak detection on gas pipelines

Sara T. Baltazar
UTAD
T-P Azevedo Perdicoulis
ISR Coimbra and UTAD
Paulo Lopes dos Santos
FEUP

Focus on the simulation of pipeline dynamic models and aiming to develop new leakage detection/location techniques; this paper presents four quadripole models to describe the natural gas pipeline dynamics, using an electrical analogy. The models provide boundaries and intermediate pressure and mass flow values along the pipeline, allowing for the analyses of discrepancies between simulated and real pressures and mass flow values and detect when there is a leak. Those simulations will be discoursed in the presentation along the validations of the models with real data.

Adaptive Spatial Meshes in Pipeline Models

Jason Modisette
Atmos International

Pipeline simulation always brings up the question of which mesh (or “knot spacing”) to use. Mesh issues don’t really have anything to do with pipelines, and it would be nice if the pipeline modeler didn’t have to think about them. This is the promise of an automatically adaptive mesh. Ideally, adaptive techniques will add mesh points when and where they’re needed, get rid of them when they aren’t, and maintain a guarantee that the model solution is accurate to some userspecified level. This paper explores approaches to deciding when to add mesh points and the interaction between the spatial mesh and the model time step. The author will compare model speed and accuracy between automatic and hand-optimized meshes and will discuss the benefits and problems he has encountered in a decade of adaptive mesh use.

Surge Events and Modeling on Large Water Distribution Pipelines in Oil Sands Developments

David Cheng, Garrett Bruce
Fluor Enterprises, Inc.

Large water pipeline systems are crucial components in oil sand production. Hydraulic surge analysis is important in the design and operation of these systems to assure economic and reliable water supply. This paper summarizes the transient modeling strategy and identifies common causes and solutions to surge or low pressure issues in the system. This paper also illustrates the consideration and modeling technique in entrapped air effects on the water system surge using single phase pipeline hydraulics software.

Calculation of Gas Pipeline Compressor Station Availability Factors Using the Monte Carlo Simulation Method

Matt Lubomirsky, Rainer Kurz, Roman Zamotorin
Solar Turbines, Inc.

This paper discusses the use of a Monte Carlo simulation to determine the flow availability of a pipeline, considering load profiles, compressor and turbine performance, station configuration and swings in ambient conditions.

A Thermal Analysis of a CO2 Transportation Pipeline: a Design Configuration for Optimum Onshore Transportation

Ahmed Saad, Hamed Aghajani, Ben Wetenhall
Newcastle University
United Kingdom

Ibrahim Ahmed
Missouri University of Science and Technology

Heat flux out from a pipeline during onshore transportation can have a significant effect on the surrounding soil, causing the premature fertilisation of plants along the pipeline route. A numerical investigation of CO2 and natural gas (NG) transmission pipelines under steady state heat transfer is conducted to demonstrate the quantity of heat released from the pipelines. The results demonstrate that there is significant difference in temperature dissipation in NG pipelines compared with CO2 pipelines.

LNG Supply Optimization and Scheduling during Peak Demand at PGN West Java Network

M Subhan Missuari, Arief Mujiyanto,
Zulkarnaen
PT. Perusahaan Gas Negara (Persero) Tbk.

Paul Dickerson
Energy Solutions International, Ltd

Kwantip Konakom
Emerson (Thailand) Limited

This paper discusses the application of steady state and transient simulation in PGN West Java pipelines to fulfill power plant peak load requirement by utilizing the available connection of an LNG regasification facility within the gas networks. The presentation will discuss the simulation steps, implementation within Gas Control, and the additional capacity outcome.

Real-Time Simulation System

Vadim Shapiro, Daniel P. Theis
Statistics and Control

This paper discusses the concerns that must be addressed to accurately simulate the transportation of multiphase mixtures across industrial scale pipelines, included in that discussion are the equations that are used by the simulation software to model multiphase flow processes. The paper concludes with a report of the results of a simulation of an existing commercial pipeline.

Pipeline Operator Training System as a Leak Detection Performance Test Bed

Samir Dagher, Hamid Khakpour, Steven Francisco
Schneider Electric

This paper describes the use of an Operator Training System (OTS) as a RTTM Leak Detection System (LDS) test bed. The OTS used is a duplicate of a production system environment which allows for the accurate replication of production system response with the capability of including device level failures for transmitters, equipment states, communication failures, and actual leaks. With this platform, leak detection response is evaluated for a variety of normal and abnormal operating conditions in steady state and transient operation.

Markov Chain Monte Carlo Based Error-in-Variable Model (EVM) for Estimating Internal Wall Roughness of Complex Gas Pipeline Networks

Teresa Leung, Trevor Glen
NOVA Centre for Applied Research

Will Runciman
TransCanada PipeLines Limited

This paper discusses the application of Markov Chain Monte Carlo simulation to estimate the degradation of gas pipeline internal surface roughness using pressure and mass flow data. Details on the methodology as well as analysis performed using historical data will be presented.

PAPER NUMBER

Building a System Sensitivity Map: A Case Study
Juan Carlos Unriza
Ecopetrol
Rafael Noguerol
Energy Solutions International

Colombian oil company, Ecopetrol, followed a practical procedure for determining the system leak sensitivity map in a new pipeline in the commissioning phase. This paper describes the approach followed during model construction, the testing scenarios design, and the results obtained. API 1149 steady state and transient predictions are also compared with the model results.

Evaluation of Internal Leak Detection Techniques
Yue Cheng, Shawn Learn, Daniel Cochran, Ehsan Shahidi
Ryan Dolan
TransCanada

This paper describes a systematic approach of evaluating the various leak detection methodologies against specific design criteria. It describes the strengths and limitations of various leak detection techniques for a particular set of leak characteristics, operating conditions, physical design considerations, commercial implications and full lifecycle cost. The paper proposes that a qualitative or semi-quantitative analysis on individual pipelines over all expected operating conditions can determine the best technology(s) to mitigate the risk of leaks in pipelines.

Practical Theft Detection & Location Under Pipeline Shutdown Condition Using an RTTM Model: A Case Study
Narasinga Rao G
Hindustan Petroleum Corporation Ltd.
Dr. Jon Barley, K V Siva Rao, M.S.R.K.Bose, R Srinivasu
Energy Solutions International

This paper presents an investigation into the detection and location of the theft of small volumes of petroleum products under low pressure conditions in a pipeline that passes underneath a major city in India. The background, circumstances and post-mortem analysis of available data is discussed.

Gas Pipeline Leak Detection: A Tutorial
Ed Nicholas
Nicholas Simulation Services
Philip Carpenter
Serrano Services
Morgan Henrie
MH Consulting

In 2013, NTSB recommended that gas pipelines should consider the installation of leak and rupture detection systems. This paper examines the feasibility of using real time transient model (RTTM) based methods to detect and locate leaks in gas pipelines. It elucidates the factors that must be managed for effective gas pipeline leak detection, and examines and quantifies the factors that impact leak detection and location sensitivity. Special attention will be given to rapid detection and “pinpointing” of large ruptures. This tutorial demonstrates the response of gas pipelines to a leak, examines how an RTTM approach can be used to detect leaks, and then moves into practical considerations such as the impact of instrumentation spacing, time skew, measurement noise, temperature uncertainties, data acquisition rates, and unmetered flows.

A Novel Stress Test Approach for Leak Detection CPM Systems with Dual
Thresholds

Jianping Gao, Daniel Hung, Norense Okunghowa, Ron Threlfall, Ray Philipenko
Enbridge Pipelines Inc.

The paper proposes a novel approach to an API RP 1130 recommended test method that can be applied to stress test CPM sensitivity, providing an evaluation of CPM robustness over a range of varying operating scenarios. The new method is tested and compared to API RP 1130 recommended leak test
methodologies. The results indicate that the proposed technique has far wider testing coverage compared to existing approaches and appears promising for use in stress testing sensitivity of CPM systems to gain an understanding of CPM robustness, which in turn has significantly improved the sensitivity of Enbridge’s current leak detection systems.

Overview of Enbridge Rupture Recognition Program

Norense Okungbowa, Martin Di Blasi, Zhan Li
Enbridge Pipelines, Inc.

This paper provides an overview of the Enbridge Pipeline Rupture Recognition Program (RRP). The RRP considered different rupture detection approaches, ranging from improvements to existing CPM leak detection to the development of new SCADA based rupture detection algorithms. The presentation will discuss some high level results and share learnings from work completed to date.

The API 1149 Update, Model-Based Leak Detection Uncertainty Assessment

Nikolaos Salmatanis
Chevron Pipeline Co

Jon Van Reet
Plains All-American Pipeline Co.

Kunal Dutta-Roy
EICE

David Shaw
TT Consulting

This paper provides an overview of the revised API procedure 1149 regarding the uncertainty of software-based Computational Pipeline Monitoring leak detection systems. The paper focuses on the utilization of transient pipeline simulation models as the Reference Model. The process of identifying and prioritizing the key areas of input uncertainty is highlighted. In particular, experience in running the procedure for LVL liquids, HVL liquids and natural gas pipelines are discussed.

Pipeline Leak Location Using Optimization Method

Buzhou Wu, Zhengtao Ding
University of Manchester

This paper presents some theoretical and experimental results of a new modelbased optimization method for leak location on liquid pipelines. Based on a transient flow model, our proposed method formulates the leak location problem into a minimization problem by introducing a cost function which quantifies the deviation between modelled and measured flows. The minimization problem is then effectively solved by using a derivative-based search algorithm. This method has been tested using measured data of six leak trials from an operational pipeline, which shows that the proposed method is more accurate and reliable than conventional methods based on pressure gradient.

Automated Compressor Station Location in Natural Gas Pipelines

Andrew Daniels
DNV-GL

During the process of planning transmission pipeline expansions, engineers must determine which pipe diameters to use as well as where to locate compressor stations. Historically, much of the research related to gas transmission pipeline design focuses on finding the single, least cost optimum pipeline design. However, there are sometimes reasons why this single, least cost solution may not be the most desirable design for a pipeline. This paper presents an automated technique for locating compressor stations within a pipeline based on pipeline and compressor constraints. The technique can be used to perform parametric studies aiding in the design of natural gas pipelines.

A Contribution to Modeling of Centrifugal and Axial Compressors

Marko Haulis
SIMONE Research Group

This paper concerns mathematical description of centrifugal and axial compressors, the most frequently used equipment in gas transportation pipelines or pipeline networks. It contains a new way of modeling the compressors that cannot be modeled in traditional ways, with robust algorithms and proven mathematical methods.

Advanced Analytics for Continuous Emission Monitoring Systems

Vadim Shapiro
Statistics & Control, Inc.
Dmitriy Khots
iMath Consulting

This paper focuses on advanced analytics that can be used to provide reliable and accurate service, even when extractive Continuous Emission Monitoring Systems (CEMS) are off-line, data are missing, or if a monitoring system is not installed. The presentation describes the data used for the advanced analytics, predictive modeling techniques, and optimization
methodology.

Centrifugal Compressor Performance Modeling & Monitoring

Todd A. Barham
BHP Billiton

This paper proposes a new method of modeling the compressor performance apart from lookup tables and fan laws. It will offer that compressor performance is modeled using non-dimensional performance parameters. The paper utilizes work, head, and flow non-dimensional coefficients to model
compressor variability and indicate when there is a compressor performance problem. The paper recommends utilizing real time input data and response capabilities.
Through the methods proposed, a user will have a realistic performance model, and a performance monitoring and alert system that can be used as a real-time feedback mechanism into the gathering system model.

Exergetic Analysis: A Tutorial

Brett Christie

Energy Solutions International

The concept of exergy is defined and explained with the intention of its direct application toward pipeline simulation. A pipeline ‘transportation module’ is introduced with a numerical solution, and efficiency for it is defined in terms of exergy. Case studies are presented showing the direct application of this transportation efficiency.

Comparative Analysis of Selected Implicit Finite-Difference Schemes for
Solving Systems of One-Dimensional Hyperbolic Equations

Andrzej J. Osiadacz, Maciej Chaczykowski
Warsaw University of Technology

The main goal of the analysis is to choose the most effective scheme for transient simulation of large-scale fluid network with non-pipe elements. The numerical examples are provided and their results are analyzed based on mass/momentum/energy balance errors, number of discretization intervals, and number of iterations in the solution procedure.

Depressurization of a Gas Reservoir by a Pipe of Arbitrary Length

Rudolf Hajossy, Igor Mračka, Tibor Žáčik
Mathematical Institute, Slovak Academy of Sciences

This paper deals with the gas reservoir and the blow-off pipe as a unit. Implicit relations for sonic and subsonic outflows through pipes of any length are presented. Explicit approximate relations are provided as well. The formulas have been applied to determine valve influence on depressurization and blowthrough of a compressor yard. The theoretical results have been verified by experimental data.

Steady-State Temperature Predictions of Commercial Pipeline Simulators

Sigmund Clausen
Polytec, Norway

Svein-Erik Losnegård, Willy Postvoll, Leif Idar Langelandsvik
Gassco, Norway

This paper describes the benchmarking of three different commercial pipeline simulators with respect to differences in predicting steady state temperature profiles. The calculated temperature profiles are compared to NIST data for adiabatic conditions, and to the simple pipe cooling law when heat transfer from the ambience dominates. In addition, a comparison with temperature measurements from a pig is given, and the validity of the temperature measurements is discussed.

Overcoming the Challenges of Modeling Midstream Gathering Systems

Clay Noble
Targa Resources

James M. Gregg, Samon Kashani
Gregg Engineering

The ever changing and complex nature of midstream gathering systems presents an inherent challenge to pipeline simulation modeling. In this paper we present methods for building simulation models from GIS to handle inevitable changes to the system, introduce new and sophisticated solutions to calibrate models using SCADA data so as to maintain model accuracy and help identify areas of probable liquid hold up, and show how simulation is used to solve specific operational and design problems in a gathering system.

Tuning Mid-Line Deliveries and Injections in Online Models

Jason Modisette, Victor Mora
Atmos International

Both gas and liquid pipelines commonly have small deliveries or injections in the middle of the pipe. Some online model applications, such as leak detection, benefit from being able to use the pressure meter at such a mid-line delivery as a boundary condition. In other online applications, the flow meter there may not be read often enough to drive an online model, which also suggests using the pressure meter. However, actually using a mid-line pressure meter as a RTTM boundary condition can be tricky: without careful tuning, the error in the delivered/injected flow can easily be 100% or more of the measured value. This paper examines possible tuning parameters and tuning goals for such a situation.

Balancing of Transmission System and Contracts in Energy Units Based
on Simulation Results

Stanisław Brzęczkowski, Magdalena Głębocka, Maciej Szeniawski
GAZ-SYSTEM S.A.

The paper presents the possibility of replacing the gross calorific value measurements for the individual exit points with simulation results verified by the measurements of reference gas. The results of the simulation are used for transport and balancing settlement proposes and optimization of market based system services used for ensuring integrity of system.

Study on the Key Technology of Simulation Training Systems of the
Large-Scale and Central Controlled Gas Pipe Network

Zheng Jianguo, Kang Yang, Ai Muyang
PetroChina Pipeline R&D Center

This paper discusses the key technology of simulation training systems of the large-scale and central controlled gas pipe network. The presentation will discuss the characteristics of the large-scale and central controlled gas pipe network, the modeling approach, the solving strategy and implementing technology. An application example will also be provided.

Computing Pressure Loss in Liquid Pipelines A Historical Perspective

James C. Keiler
DNV-GL

This paper will discuss how tools used for calculating pressure loss have changed over time. The paper will begin with a discussion of the work done by Henri Darcy and Julius Weisbach that set the course of hydraulics for us 150 years ago, and the work of 20th century scientists and mathematicians to make the work of pipeline engineers more accurate and more efficiently completed. Various methodologies will be reviewed, from paper, pencil, and slide rule, to hand calculators, to the current computer-based simulation software packagesng.

A Systematic Approach to Transmission Stress Tests in Entry-Exit Systems

Jarig J. Steringa, Harry Dijkhuis,
Marco Hoogwerf
Gasunie Transport Services

This paper presents a systematic approach, based on a few simple principles, to identify a complete set of transmission stress tests in complex entry-exit systems. The presentation will give a practical introduction using simple examples, followed by a more detailed description in terms of the physics and mathematics involved. Ideas for the implementation as a pre-processing algorithm in pipeline simulation programs will be presented as well.

Impact of Gas Composition on Pipeline and Compressor Operating Conditions

Augusto Garcia, Hernandez
Adrian Alvarado, Brandon Ridens
Southwest Research Institute

This paper presents the effects on the efficiency and performance of compressors when exposed to varying natural gas compositions as well as the effect on the pipeline pressure losses and interchangeability. This paper will
also include case study results of a pipeline system and its associated compressor stations.

Pipeline Optimization Using DRA Degradation Models

Juan Carlos Unriza, Jose Lara, Christian Reyes
Ecopetrol
Paula Cuero
SCN-Lavalin

This paper presents a DRA Degradation Model developed inside a Colombian Pipeline Operator verified with field tests in pipelines that underwent structural modifications, and where the DRA injection constitutes a normal operation mode. These modifications generated shear stresses sources and the DRA’s Drag Reduction Effect was affected. This paper describes the methodology used to model the DRA degradation generated by shear stresses with dynamic simulations. This research allows the Colombian Pipeline Operator to accurately develop the optimization processes without affecting flow capacity or overdosing DRA. This resulted in the Company´s projects being made feasible and the return on investment increased.

Accurate Natural Gas Load Hourly Forecasting Using Artificial Neural
Networks Model Trained with Multiple Parameters

Dongmin Qian
Energy Solutions International

Patrick H. Fox, Bernard L. See
Dominion Resources, Inc.

This paper discusses a natural gas hourly load forecasting system using Artificial Neural Network method to provide future hourly forecast with up to 95% accuracy. The presentation will discuss how this system is configured, the data selection for the model training and the forecast results. A demo of the program will also be provided.