PSIG 2102 – New Rupture Detection Data Mining Algorithms for Crude Oil Pipelines
Yavuz Yilmaz (Emerson)

In our study, a 36” crude oil pipeline with 2 pump stations was configured in a pipeline simulator. The pipeline parameters of flow, pressure and temperature were computed for a number of leak and rupture cases and data mining algorithms such as Logistic Regression, Neural Network and Multivariate Adaptive Regression Splines (MARS) were used as classifiers to detect the leaks and ruptures. MARS proves itself as a comparative classifier to the already known logistic regression and neural network methods as new leak and rupture detection computation data mining technique for pipeline operators.

PSIG 2103 – Performance of CPM Based Leak-Detection Algorithms in the Presence of Slack
Hamed Ghasvari Jahromi, Fatemeh Ekram, Michael Roxas, Waqar Ali, Satya Mokamati (Vanmok Leak Detection Technologies Inc.)

One of the major complexities in the leak detection process arises when the leak happens in a pipeline undergoing phase change. This paper investigates the quality of leak detection algorithms with and without the ability to take phase change (cavitation) and presence of vaporous phase (slack) into account. The results of the experiments conducted on a 374-meter (1227-ft) pipe, emphasize the importance of the phase change modeling ability of the CPM to avoid false positives and detect the leaks of different types, which would have otherwise been masked under operating conditions that involve phase change.

PSIG 2104 – Flow Assurance – How to Reduce the Capacity of the Slug Catcher
Luciano Langhi, Dulce Gomez (Transportadora Gas Del Sur S. A.)

The paper provide information about the flow assurance simulations that allowed TGS to operate its biphasic system, with more than 20,000 cubic meters (76,00 cubic feet) of liquid inside, without pigging and minimizing the slug catcher volume.

PSIG 2105 – A Novel Approach for Pump Timing Optimization to Avoid Pipeline Over Pressurization
Andrew Yule, Eric Smith (Assured Flow Solutions)

This paper discusses the development of a new methodology that looks to optimize the timing of pumps involved in LACT units. Rather than isolating wellsite pumps from their downstream pipelines, in this new approach, the entire field is modeled together and directly combined with an optimization routine such that the objective function is minimized with fewer evaluations. The results provide a more accurate convergence to an optimal solution while eliminating the need for a brute force parametric study allowing the solution to scale to very large and complicated systems.

PSIG 2108 – How to Use Pipeline Models to Manage Nominations and Allocations in a Constrained and Highly Dynamic Network
G. Giannatos (Australian Energy Market Operator)
J. Fryatt & C. Davison (DNV)

This paper investigates the technology and business benefits of a web based model scheduling application, which integrates a transient model to other business applications that provide injection and demand schedules. The application provides a simple method to input complex scenarios, including compressor, regulator, and routing operations. The paper shows how the system allows non–modellers to use a complex transient model, reducing bad operational decisions which could impact the wholesale natural gas price or supply to end user customers such as households or businesses. Other operational metrics are discussed.

PSIG 2106 – Regulator Station Risk Model Supported by a Parametric Study Cloud Application
Corey Rice (DNV)

Utilities delivering natural gas to residences and businesses at lower pressures are under increasing scrutiny from federal, state and/or municipal regulators to demonstrate a commitment to safety. One way to do this is by using an analytical risk model to quantify the risk of the overall system and individual assets. Oftentimes the risk for pressure reducing regulator stations is determined similarly as other types of assets in a gas network, and inputs may call for an engineer’s estimation. This paper describes the beginnings of a novel approach of applying hydraulic analyses via parametric study in the cloud to refine and enhance these analytical regulator station risk models.

PSIG 2109 – Prediction of Sand Transport in Horizontal and Inclined Flow Based on Machine Learning Algorithms
Ronald E. Vieira, B. Xu, Siamack A. Shirazi (University of Tulsa)

This paper presents a framework to predict critical velocities in pipes via machine learning (ML) using accessible parameters as inputs, namely, fluid and particle properties and inclination angles. The ML algorithms are trained on a large dataset of critical velocities in single-phase carrier fluid that is collected from open source: articles and dissertations. The trained algorithms are Linear Regression, Random Forest, Support Vector Machine and Gradient Boosting Decision Trees. Moreover, the influence of key features in critical velocity prediction was identified by the applied algorithms. Finally, the predictive abilities of the models are cross-compared and were further validated by comparing its performance with well-established mechanistic models based on empirical correlations. The ML approach is observed to have superior performance to other models across a wide range of flow conditions and inclination angles.

PSIG 2110 – Transporting Hydrogen-Natural Gas Mixtures
Rainer Kurz, Matt Lubomirsky, Roman Zamotorin (Solar Turbines Incorporated)

To assess the impact on the addition of hydrogen in various concentrations to a natural gas pipeline, a realistic pipeline system is simulated. The pipeline hydraulic simulation will provide the necessary operating conditions for the gas compressors, and the gas turbines that drive these compressors. As results of the study the impact on transportation efficiency in terms of energy consumption as well as the impact on the transport capacity of a pipeline where the equipment was sized originally for natural gas transport, are assessed. Necessary concepts in the capability to store gas to better balance supply and demand are discussed, too.

PSIG 2111 – Building an Integrated Operator Training System for a Complete Training Experience
James McFall, Joe Reynolds (AVEVA)

The purpose of a pipeline Operator Training System (OTS) is to train operators in an offline environment, while giving the look and feel of real-world operations. This paper will discuss the challenges and solutions found during the development of an OTS that integrates liquid and gas pipeline operation, pump station power plant startup, PLC control, and power distribution management models. These models were integrated in such a way as to give an operator fully comprehensive training on every aspect of the real-world system included in their operating responsibility.

PSIG 2113 – Verification, Validation, Uncertainty Quantification Issues in the Development of Artificial Intelligent Models in Flow Assurance
David Cheng (Fluor)

The paper introduces Artificial Intelligence methods that are ready to be used in flow assurance. The model Verification, Validation, and Uncertainty Quantification methods are discussed and demonstrated. Extensibility of AI model based on limited range of data is discussed.

PSIG 2114 – Surge Phenomena in Flexible Hoses of Offshore Loading Systems
Guohua Li, Noorallah Rostamy & Hamid Bidmus (DNV)

Offshore loading systems provide products to tankers through flexible hoses. The flexible hoses can experience surges initiated by a valve closure. In this paper, surge studies are carried out for two common configurations of “tandem” and “buoy” loading systems. The results show much lower surge pressures in flexible hoses than those in carbon steel pipes due to the different elasticities of their material. The results also show that loading rates and valve closure time play a key role in potential-dominated surges which are the case for “tandem” configuration, whereas for line pack dominated operations in the “buoy” configuration, timely cutoff of the flow by closing a valve at the pipeline end manifold (PLEM) is imperative.

PSIG 2115 – An Integrated Solution for Planning and Operating Power-To-Gas Facilities in Coupled Gas and Electricity Networks
Dominique Adolfo, Carlo Carcasci (University of Florence, Department of Industrial Engineering, Florence, Italy)
Kwabena Addo Pambour, Carlo Brancucci (encoord GmbH, Essen, Germany, encoord Inc., LLC, Denver, Colorado, USA)

This paper discusses the value of simulation models for planning and operating Power-To-Gas, Power-To-Pressure, and Gas-To-Power facilities located at the interface between gas and electricity networks. A mathematical model is developed and applied on a future scenario of a bidirectionally coupled real gas and electricity network to demonstrate how the model can assist strategic network planners and operators to plan and coordinate the interactions between coupled gas and electricity systems.

PSIG 2116 – Ingress Detection in Deep Subsea Gas Pipelines
G.P. Morrow, J.J. Barley (Emerson)

In deep subsea transmission pipelines, exterior pressure from the water column can exceed gas pressure inside the pipeline, particularly toward the delivery end. In those regions, a loss of containment will result in water ingress into the pipeline instead of gas egress. We present the results of multiphase simulation of ingress in such pipelines. Ingress is interpreted in effect as a regulator setting pressure at the ingress location and providing a constriction to gas flow. Ingress may be detected as a conventional leak and distinguished by phenomenological effects.

PSIG 2118 – Optimal Parameter Estimation for Efficient Transient Pipeline Simulation
Cody Allen, Chad Holcomb, Roman Zamotorin, Rainer Kurz (Solar Turbines Incorporated)

Software for the simulation of the transient behavior of natural gas pipelines have high computational demands. Further, they are difficult to set up if the goal is to match measurement data from SCADA systems or compressor stations for existing pipelines. To overcome this difficulty, a state space approach is used to capture the transient behavior of the pipeline. The general approach takes a published method from the literature that derives transfer functions and state space equations from one-dimensional Navier-Stokes and extends the method to include compressor stations and full pipelines. The present method is validated against results in the literature and against a complete pipeline model using commercially available software.

PSIG 2119 – Using Transient Pipeline Simulation to Evaluate Electric Power Generation Reliability
Ignacio Losada Carreño, Anna Scaglione (Arizona State University)
Anthony Giacomoni (PJM Interconnection)
Kaarthik Sundar, Deepjyoti Deka, Anatoly Zlotnik (Los Alamos National Laboratory)

Many electric power systems now rely on natural gas pipeline networks to supply fuel for gas-fired generation. In this study, we quantify the impacts of gas pipeline constraints and contingencies on the reliability of power generation and transmission, particularly during extreme events. We use a stochastic model to quantify the impacts of unplanned events that may cause curtailments to gas-fired generators that do not hold firm pipeline capacity contracts. The physical and operating state of the natural gas and power systems are evaluated for different realizations of the stochastic process. Power system day-ahead scheduling is modelled by a security-constrained unit commitment optimization, and real-time generation re-dispatch and reserve allocation is modeled using DC optimal power flow. Transient pipeline optimization is used as a proxy for human operator actions, and impacts of real-time contingencies are evaluated using transient pipeline simulation. This approach can uncover vulnerabilities for which remedial corrections can be taken, and could be used to develop reliability standards.

PSIG 2120 – Experimental Investigation of Two-Phase Flow Patterns in Circular and Triangular Pipes
Ronald E. Vieira, Siamack A. Shirazi (University of Tulsa)
Gabriel Silva (TechnipFMC)

The present investigation was to study the effects of triangular pipe geometry and orientation on flow patterns, slug frequency, and liquid film dryout in gas-liquid flows. Different understandings of two-phase flow regimes affected by the shapes of the cross-sections of the channels were obtained by flow visualization with the aid of a digital high speed video camera. The following flow patterns at different air and water superficial velocities were recognized for both pipe geometries: slug flow, pseudo-slug flow, stratified-wavy flow, and annular flow. Visual observations revealed that the slug frequency in the triangular channel is lower than the frequency obtained in the circular pipe. Empirical correlations are validated to predict slug frequencies in triangular and circular pipes.

PSIG 2124 – When is the Ideal Time for Pipeline Companies to Migrate from Legacy Scheduling Applications to Standard Solutions? – A Parameters, Processes and Systems Perspective
Prasad Challa (Emerson)

This paper provides experiences of implementations on liquid pipeline scheduling solutions and their varying level of user acceptance. The paper highlights common reasons that hinder a scheduler from fully utilizing an available system. The paper identifies the most common amongst these which when provided may enable a higher user level acceptance of an implementation. The paper also tries to define the optimal time when a pipeline company with a medium to complex pipeline network should consider migrating from a legacy application to a standard, or a tailor made, solution by considering the level of maturity of systems and the processes that exist at various levels within the organization.