Field Testing of Negative-Wave Leak Detection Systems

2014 ◽  
Author(s):  
Shane Siebenaler ◽  
Eric Tervo ◽  
Paul Vinh ◽  
Chris Lewis
Keyword(s):  
Response Times ◽  
Dynamic Pressure ◽  
User Interaction ◽  
Field Testing ◽  
Leak Detection ◽  
Operating Conditions ◽  
Negative Wave ◽  
Oil Pipeline ◽  
Detection Systems ◽  
The Cost

The pipeline industry is improving its ability to detect and locate leaks through emerging technologies. There has been a variety of research in recent years aimed at further development of sensor-based technologies for leak detection. A key obstacle to retrofitting existing pipelines with leak detection technologies is the cost and risk of installing hardware, particularly those sensors that require excavation near the pipe. There are many advantages to employing leak detection systems that can leverage existing instrumentation access locations. One such technology may be negative-wave leak detection systems. Negative-wave technologies work by measuring dynamic pressure changes in the pipe. It should be noted that some negative-wave systems require line modifications to accommodate multiple transmitters. While such systems have been on the market for many years, there is insufficient data available about their performance under various pipeline operating conditions for widespread adoption. In an effort to close many information gaps on the performance envelope of negative-wave technologies, a PRCI-funded field test was performed on a 41-kilometer segment of a 30-inch diameter heavy crude oil pipeline. Products from three suppliers were installed at either end of the test segment. Actual commodity withdrawals were conducted at a remote valve site approximately 21 kilometers into the segment during various operations to test the systems’ abilities to detect the withdrawals without direct user interaction. These test points included withdrawals during steady-state flowing, pump startup, and shutdown conditions. Data were collected from each system to determine their abilities to detect leaks under various conditions, abilities to locate the leak, false alarm rates, and response times. This test provided significant insight into the performance of such systems over the range of conditions tested. The key focus of this paper is the approach for conducting such multi-vendor commodity withdrawals. This project required some unique considerations for its execution. Such considerations are also documented to provide input to others who are considering such a test.

Behavioral Analysis of Drivers Following Winter Maintenance Trucks Enabled with Collision Avoidance System

2019 ◽  
Vol 2673 (10) ◽  
pp. 394-404
Author(s):  
Rajat Verma ◽  
Ramin Saedi ◽  
Ali Zockaie ◽  
Timothy J. Gates
Keyword(s):  
Collision Avoidance ◽  
Traffic Safety ◽  
Response Times ◽  
Regression Tree ◽  
Field Testing ◽  
Operating Conditions ◽  
Classification And Regression Tree ◽  
Crash Risk ◽  
Winter Maintenance ◽  
Warning Light

Winter maintenance trucks (WMTs) often operate at lower speeds during inclement weather and roadway conditions, creating potential safety issues for motorists following close behind. In this study, a new prototype radar-based rear-end collision avoidance and mitigation system (CAMS) was tested to assess its impact on the behavior of drivers following WMTs. The system is designed to flash an auxiliary rear-facing warning light upon detection of a vehicle encroaching within an unsafe relative headway with the rear of the WMT. A series of field evaluations was performed during actual winter maintenance operations to assess the effectiveness of the system compared with normal operating conditions (i.e., without the CAMS warning light) toward improving driver behavior related to rear-end crash risk. Specifically, two measures were assessed: (a) rate of vehicles encroaching beyond a safe time headway threshold to the rear of the WMT, and (b) the reaction–response time of drivers. Classification and regression tree models were created for identifying the relevant factors influential in determining the change in driver response. The results indicate that this warning light was effective in reducing the likelihood of the subject drivers crossing beyond a relative headway of 4.5 s. It was also effective in reducing the reaction and response times of the drivers by 0.83 and 0.55 s (36% and 20% reduction), respectively. Although the results were encouraging, additional field testing is recommended before conclusions are drawn regarding the traffic safety impacts of the system.

Improved Leak Detection by Method Diversity

1998 ◽  
Author(s):  
Ruprecht M. J. Pichler
Keyword(s):  
Transient Flow ◽  
Detection System ◽  
Type System ◽  
Leak Detection ◽  
Operating Conditions ◽  
Detection Methods ◽  
Special Focus ◽  
Oil Pipeline ◽  
Knowledge Based ◽  
Noise Factors

Leak detection systems for liquid pipelines are installed to minimize spillage in case of a leak. Therefore reliability, sensitivity and detection time under practical operating conditions are the most important parameters of a leak detection system. Noise factors to be considered among others are unknown fluid property data, friction factor, instrument errors, transient flow, slack-line operation and SCADA update time. The opening characteristics and the size of leaks differ considerably from case to case. Each software-based leak detection method available today has its particular strength. As long as just one or two of these methods are applied to a pipeline a compromise has to be found for the key parameters of the leak detection system. The paper proposed illustrates how a combination of several different software-based leak detection methods together with observer-type system identification and a knowledge-based evaluation can improve leak detection. Special focus is given to leak detection and automated leak locating under transient flow conditions. Practical results are shown for a crude oil pipeline and a product pipeline.

Real Time Statistical Leak Detection on the RRP Crude Oil Network, Holland

2002 ◽  
Author(s):  
Joep Hoeijmakers ◽  
John Lewis
Keyword(s):  
Crude Oil ◽  
Real Time ◽  
Detection System ◽  
Leak Detection ◽  
Field Application ◽  
Normal Operation ◽  
False Alarms ◽  
Pipeline Network ◽  
Oil Pipeline ◽  
Detection Systems

Prior to the year 2000, the RRP crude oil pipeline network in Holland and Germany was monitored using a dynamic leak detection system based on a dynamic model. The system produced some false alarms during normal operation; prompting RRP to investigate what advances had been made in the leak detection field before committing to upgrade the existing system for Y2K compliance. RRP studied the available leak detection systems and decided to install a statistics-based system. This paper examines the field application of the statistics based leak detection system on the three crude oil pipelines operated by RRP. They are the 177 km Dutch line, the 103 km South line, and the 86 km North line. The results of actual field leak trials are reported. Leak detection systems should maintain high sensitivity with the minimum of false alarms over the long term; thus this paper also outlines the performance of the statistical leak detection system over the last year from the User’s perspective. The leak detection experiences documented on this crude oil pipeline network demonstrate that it is possible to have a reliable real-time leak detection system with minimal maintenance costs and without the costs and inconvenience of false alarms.

Formulation and Analysis of the Probability of Detection and False Detection for Subsea Leak Detection Systems

2014 ◽  
Author(s):  
Alireda Aljaroudi ◽  
Faisal Khan ◽  
Ayhan Akinturk ◽  
Mahmoud Haddara ◽  
Premkumar Thodi
Keyword(s):  
Oil And Gas ◽  
Detection System ◽  
Oil And Gas Industry ◽  
Leak Detection ◽  
Probability Of Detection ◽  
Operating Conditions ◽  
False Detection ◽  
Potential Threat ◽  
Probability Of False Alarm ◽  
Detection Systems

Insuring the integrity of subsea process component is one of the primary business objectives for oil and gas industry. One of the systems used to insure reliability of a pipeline, is the Leak Detection System (LDS). Different leak detection systems use different technologies for detecting and locating leaks that could result from pipelines. One technology in particular that is gaining wide acceptance by the industry is the optical leak detection systems. This technology has great potential for subsea pipelines applications. It is the most suited for underwater applications due to the ease of installation and reliable sensing capabilities. Having pipelines underwater in the deep sea present a greater challenge and a potential threat to the environment and operation. Thus, there is a need to have a reliable and effective system to provide the assurances that the monitored subsea pipeline is safe and functioning as per operating conditions. Two important performance parameters that are of concern to operators are the probability of detection and probability of false alarm. This article presents a probabilistic formulation of the probability of detection and probability of false detection for fiber optic LDS based systems.

Математический алгоритм для обнаружения утечек малой интенсивности

2021 ◽  
pp. 528-534
Author(s):  
Ivan N. Loginov ◽  
Sergey A. Korshunov
Keyword(s):  
Dynamic Pressure ◽  
Operating Mode ◽  
Noise Component ◽  
Oil Pipeline ◽  
Mathematical Algorithm ◽  
Detection Systems ◽  
Noisy Signals ◽  
Control Section ◽  
Actual Flow ◽  
Main Oil Pipeline

The operating principle of leak detection systems, based on registration of transported medium hydroacoustic fluctuations, appearing due to pipeline loss of containment, consists of identification of hydraulic impulse, originating in case of leakage, using acoustic dynamic pressure measuring sensors - hydrophones. However, during pumping at pipeline stationary operating mode hydrophones also register background noises, which can mask the leakage signal. To separate the useful leakage signal it is important to construct an algorithm that allows lowering the noise component of the signals. Within the scope of experimental research, two pairs of hydrophones were used, which were installed at the functioning main oil pipeline at a distance of 20 km of each other. The distance between the adjacent paired hydrophones was no more than 1 km. Leaks were imitated by draining the product (diesel fuel) in the middle of control section. Authors considered the methods of noisy signals filtration and possible methods of cleared signals processing to determine the leak parameters. Mathematical algorithm that allows minimizing the influence of signal noise by filtration and mutual hydrophone readings compensation was proposed. It is established, that the developed algorithm allows detecting the leakages of low intensity (up to 0.1 % of actual flow) in cases of stationary pipeline operating mode and pumping stop mode. Принцип работы систем обнаружения утечек, основанных на регистрации гидроакустических колебаний транспортируемой среды, возникающих из-за разгерметизации трубопровода, состоит в идентификации гидравлического импульса, возникающего при образовании утечки, с помощью акустических датчиков измерения динамического давления – гидрофонов. Однако гидрофоны в процессе перекачки при стационарном режиме работы трубопровода регистрируют в том числе фоновые шумы, которые могут маскировать сигнал от утечки. Для выделения полезного сигнала утечки актуально построение алгоритма, позволяющего понизить шумовые составляющие сигналов. В рамках экспериментальных исследований использовались две пары гидрофонов, которые устанавливались на действующем магистральном нефтепродуктопроводе на расстоянии 20 км друг от друга. Расстояние между соседними гидрофонами в паре составляло не более 1 км. Утечки имитировались путем выполнения натурных сливов продукта (дизельного топлива) в середине контрольного участка. Авторами рассмотрены методы фильтрации зашумленных сигналов и возможные способы обработки очищенных сигналов с целью определения параметров утечки. Предложен математический алгоритм, позволяющий минимизировать влияние шумовых составляющих сигналов путем фильтрации и взаимной компенсации показаний пар гидрофонов. Установлено, что разработанный алгоритм позволяет обнаруживать утечки малой интенсивности (до 0,1 % от фактического расхода) в условиях стационарного режима работы трубопровода и режима остановленной перекачки.

scholarly journals Interactive Cost Configuration Over Decision Diagrams

2010 ◽  
Vol 37 ◽  
pp. 99-139 ◽  
Author(s):  
H. R. Andersen ◽  
T. Hadzic ◽  
D. Pisinger
Keyword(s):  
Cost Function ◽  
Response Times ◽  
User Interaction ◽  
User Preferences ◽  
Cost Functions ◽  
Product Configuration ◽  
Decision Diagrams ◽  
Important Approach ◽  
Feasible Solutions ◽  
The Cost

In many AI domains such as product configuration, a user should interactively specify a solution that must satisfy a set of constraints. In such scenarios, offline compilation of feasible solutions into a tractable representation is an important approach to delivering efficient backtrack-free user interaction online. In particular,binary decision diagrams (BDDs) have been successfully used as a compilation target for product and service configuration. In this paper we discuss how to extend BDD-based configuration to scenarios involving cost functions which express user preferences. We first show that an efficient, robust and easy to implement extension is possible if the cost function is additive, and feasible solutions are represented using multi-valued decision diagrams (MDDs). We also discuss the effect on MDD size if the cost function is non-additive or if it is encoded explicitly into MDD. We then discuss interactive configuration in the presence of multiple cost functions. We prove that even in its simplest form, multiple-cost configuration is NP-hard in the input MDD. However, for solving two-cost configuration we develop a pseudo-polynomial scheme and a fully polynomial approximation scheme. The applicability of our approach is demonstrated through experiments over real-world configuration models and product-catalogue datasets. Response times are generally within a fraction of a second even for very large instances.

Oil Pipeline Leak Detection System Based on Acoustic Wave Technology

2012 ◽  
Vol 220-223 ◽  
pp. 1628-1632
Author(s):  
Li Kun Wang ◽  
Bin Xu ◽  
Hong Chao Wang ◽  
Shi Li Chen ◽  
Jia Yong Wu ◽  
...  
Keyword(s):  
Wavelet Analysis ◽  
Acoustic Wave ◽  
Internal Pressure ◽  
Detection System ◽  
Dynamic Pressure ◽  
Field Tests ◽  
Leak Detection ◽  
Oil Pipeline ◽  
Pressure Signal ◽  
Pressure Transmitter

Principle of the pipeline leak detection system is presented, and the leak detection method based on acoustic wave and wavelet analysis is studied in this paper. The dynamic pressure transmitter based on piezoelectric dynamic pressure transducer is designed. The characteristic of dynamic pressure transmitter when pipeline leak happened is analyzed. The dynamic pressure signal is suitable for pipeline leak detection for quick-change of pipeline internal pressure, while the static pressure is suitable for slow-change of pipeline internal pressure. The signal is analyzed by wavelet analysis method to detect the singularity, and the singularity is used to recognize and locate the leak. This paper indicated that the dynamic pressure signal could be adjust to this detection that the pressure changes in the pipeline. Field tests in 68.2 km pipeline segment show that the method detects pipeline leak rapidly and precisely.

Transient Leak Detection in Crude Oil Pipelines

2004 ◽  
Author(s):  
Rainer Beushausen ◽  
Stefan Tornow ◽  
Harald Borchers ◽  
Keefe Murphy ◽  
Jun Zhang
Keyword(s):  
Steady State ◽  
Crude Oil ◽  
Pressure Wave ◽  
Detection System ◽  
Leak Detection ◽  
Statistical System ◽  
Transient Conditions ◽  
Oil Pipeline ◽  
Detection Systems ◽  
Oil Pipelines

This paper addresses the specific issues of transient leak detection in crude oil pipelines. When a leak occurs immediately after pumps are switched on or off, the pressure wave generated by the transients dominates the pressure wave that results from the leak. Traditional methods have failed to detect such leaks. Over the years, NWO has developed and implemented various leak detection systems both in-house and by commercial vendors. These systems work effectively under steady-state conditions but they are not able to detect leaks during transients. As it is likely for a leak to develop during transients, NWO has decided to have the ATMOS Pipe statistical leak detection system installed on their pipelines. This paper describes the application of this statistical system to two crude oil pipeline systems. After addressing the main difficulties of transient leaks, the field results will be presented for both steady-state and transient conditions.

Acoustic Leak Detection Technology Assessment

2012 ◽  
Author(s):  
Augusto Garcia-Hernandez ◽  
Shane Siebenaler
Keyword(s):  
Speed Of Sound ◽  
Linear Trend ◽  
Dynamic Pressure ◽  
Pressure Sensors ◽  
Initial Pressure ◽  
Leak Detection ◽  
Hydraulic Modeling ◽  
Pressure Waves ◽  
Signal Attenuation ◽  
Detection Systems

Leak detection systems are a vital part of a pipeline integrity management program. For liquid hydrocarbon pipelines, these leak detection systems can take the form of measuring conditions inside the pipeline (internal detection) or by use of hardware installed outside of the pipe (external detection). One internally-based technology is acoustic leak detection, sometimes known as rarefaction-wave monitoring. This technology is based on detecting transient pressure waves that are generated when a sudden leak occurs. Acoustic pressure waves travel in the pipeline at the speed of sound of the fluid that is being transported and can be detected by dynamic pressure sensors. Various filters and algorithms can be used to identify this disturbance and distinguish it from other pressure events on the pipeline. This architecture can even be used for noise and for signal pattern recognition to allow for automatic alarming of potential leak events. Each manufacturer of such technology applies unique algorithms or processing methods to capture and analyze the pressure signals that are used to later predict leaks and their locations. This paper presents a comprehensive review of the technical basis and methodology employed by acoustic leak detection systems in order to further understand their capabilities and limitations. This work included a vast amount of hydraulic modeling aimed at understanding the physics of wave propagation caused by leak events. Diverse parameters, such as initial pressure wave amplitude, signal attenuation, flow and pressure dependence, speed of sound effects, and sensor locations were evaluated. This modeling was conducted for a variety of simulated fluids. A proportional relationship between leak rate and the initial pressure disturbance caused by a leak was obtained. This linear trend can be used in combination with an attenuation model to calculate sensor location limitations. The work determined that the uncertainty in the speed of sound for a pipeline fluid segment significantly impacts the error bands of leak location. The modeling was used to generate correlations for signal attenuation over distance as a function of pipeline conditions.

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