Field Test of a Leak Detection System: Planning, Execution and Results

2010 ◽  
Author(s):  
Daniel Sampaio da Silva ◽  
Si´lvio A. Melo Filho ◽  
Mauro Niehues de Farias ◽  
Anderson Pacheco
Keyword(s):  
Steady State ◽  
Field Test ◽  
Communication Systems ◽  
Detection System ◽  
Transient State ◽  
Leak Detection ◽  
Point Of View ◽  
Measuring System ◽  
Operational Parameters ◽  
Pump Station

The OLAPA pipeline (Oleoduto Arauca´ria–Paranagua´) is a 12in diameter pipeline and, with its 97,6 km in length, crosses a mountain region called “Serra do Mar” attaining elevations of about 900m in a dense forest region. Besides that, this pipeline crosses cities, farms, rivers, including a short submerse stretch in the Paranagua´’s bay. An incident in this pipeline could result in severe consequences, especially under the environmental point of view. Therefore, this pipeline was chosen to test the performance of a new leak detector system in Transpetro. The test consists in comparing the theoretical results with practical values of alarm times obtained from a controlled removal of product in an adequate point, in the middle of the pipeline, simulating a real leak. The system chosen to be tested was the LeakWarn system, which is a computational system that uses the mass balance principle with line pack change to analyze the pipeline operational parameters in order to alert when there is a risk of product leak. This test had the objective to evaluate the LDS and help Transpetro’s management team to analyze and decide whether or not to replace its current leak management system, since this new one showed the expected results and was compatible with the excellence level already achieved in the company. The field test was performed in July 7th 2009, through a vent valve far from the ends of the pipeline and it was made in three different conditions: 1) A big leak in the steady state of operation; 2) A small leak also in the steady state of operation; and 3) A big leak in the transient state of operation (immediately after the pump station start up). In order to proceed this test, a multidisciplinary team was assigned and several resources were used such as: Two tank trucks, a specially designed leakage line with control valves, measuring system, flexible hoses, communication systems and emergency equipments. The complete operation was monitored from the Control Center in Transpetro’s Headquarter, Rio de Janeiro. This paper describes the way the tests were performed and presents the results in order to contribute with useful information to be used in any field test for any other leak detection system. It shows how planning were done in order to insure that all operations would be performed according to strict procedures and in a safe way. It also describes the milestones and the work of each team involved in the activity, as well as their constraints and difficulties that had to be overcome during the planning and execution phases, that lasted approximately one year.

The Design and Installation of the LEOS Leak Detection and Location System for the Northstar Project

2002 ◽  
Author(s):  
Peter W. Bryce ◽  
Peter Jax ◽  
Jie Fang
Keyword(s):  
Crude Oil ◽  
Detection System ◽  
Oil Production ◽  
Leak Detection ◽  
Army Corps ◽  
Production Facility ◽  
Plastic Tube ◽  
Pump Station ◽  
Crude Oil Production ◽  
Hydrocarbon Molecules

The Northstar project is the first crude oil production facility constructed offshore in the Beaufort Sea. Produced crude oil is transferred via a buried subsea pipeline to shore and overland to the Trans Alaska Pipeline Pump Station PS1 facility. During the permitting process, concern was expressed that a very small chronic leak in the subsea oil line would remain undetected during the winter months of continuous ice cover. Therefore, the US Army Corps of Engineers stipulated that a prototype leak detection system be installed that would capable of detecting a threshold leak less than 32 BOPD. This paper addresses the efforts to develop and install the LEOS leak detection system for arctic operations. The system is based on the well-established LEOS leak detection technology (manufactured by Framatome ANP, formerly by Siemens AG). The system comprises a perforated plastic tube with a thin water impermeable acetate outer sheath that allows hydrocarbon molecules to diffuse into the air filled tube. The air inside the tube is replaced periodically (every 24 hours) and is passed through a hydrocarbon-sensing module. The module contains resistors sensitive to the presence of very small concentrations of hydrocarbon molecules. The presence and location of a leak is determined by measuring the time taken for the localized concentration of hydrocarbon molecules associated with a leak to reach the end of the tube. LEOS components and materials were engineered to survive installation during arctic winter conditions. It was also necessary to protect the plastic LEOS sensor tube as it was lowered through the ice, attached to the pipeline, into a pre-excavated trench and then backfilled. The 10km long LEOS tube was delivered to site in 31-coiled 300m (1000-ft) bundles that were transported from Germany to Alaska. The LEOS sensing tube was preinstalled in a protective outer polyethylene tube which was unreeled through a reverse bending jig. Crude oil production started at the Northstar production facility in October 2001 and the LEOS system has been operational since then and is providing the highest degree of assurance that no oil is escaping from the pipeline.

Dual Threshold Analysis and its Tuning Tool Development for Leak Detection

2014 ◽  
Author(s):  
Jianping Gao ◽  
Mike Chen
Keyword(s):  
Steady State ◽  
Real Time ◽  
Design Process ◽  
Detection System ◽  
Leak Detection ◽  
Tool Development ◽  
Operating Period ◽  
Data Set ◽  
Threshold Setting ◽  
Threshold Tuning

Dual threshold setting in CPM (Computational Pipeline Monitoring) systems is a concept to apply two kind of thresholds, namely steady state threshold and transient threshold setting to improve sensitivity during steady state operating period and reduce false alarm rate during transient operating period. Dual threshold implementation in CPM systems is not a trivial task since a real time pipeline may go through very complicated hydraulic scenarios. During design phase of dual threshold, the data set evaluated needs to cover on operational scenario long enough to represent the typical operation of the pipeline. The design process needs to include the design of transient/steady state switching, transient and steady state threshold, waiting time etc and tuning of those design parameter to achieve the optima. This calls for effective analysis to ensure its validity and a tuning tool development with user-friendly graphical user interface (GUI) to facilitate the tuning efforts from leak detection engineers. This paper details the process from dual threshold design and analysis to tuning tool development and application of the tool in real time CPM systems. At first, the concept of dual threshold and its design process being employed in CPM systems are reviewed; Secondly the paper discusses an analysis approach in testing and evaluation of dual threshold design in current CPM systems with identification of room for improvement. Next, the paper elaborates the design and development of a dual threshold tuning tool to simplify the process with intensive application of the tool during the threshold tuning of real time CPM systems to improve the detectability of the current leak detection system, finally concludes with some closing remarks.

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.

Triggers for the Transient State of a Pipeline in Material Balance Systems Used in Real-Time Transient Hydraulic Modeling

2014 ◽  
Author(s):  
Noorallah Rostamy ◽  
Norense Okungbowa ◽  
John D. Yurchevich
Keyword(s):  
Steady State ◽  
Material Balance ◽  
Transient State ◽  
Leak Detection ◽  
Hydraulic Modeling ◽  
False Alarms ◽  
Threshold Method ◽  
Flow Meter ◽  
Transient Event ◽  
Number Of False Alarms

Computational Pipeline Monitoring (CPM) leak detection in liquid pipelines can be unreliable or have a high number of false alarms during transient hydraulic events. This paper presents techniques for avoiding these false alarms and for improving leak detectability during steady state operations. Application of this approach has improved both the sensitivity and reliability of CPM-based leak detection systems. When a pipeline is in steady-state operation, the leak detection thresholds can be reduced. When a transient is detected, the thresholds are increased to a higher value. Because of known errors in data measurement and the time at which the measurement was made, large uncertainties in the line-pack prediction can exist during these transient events. In this paper, CPM reliability is improved using dual thresholds; tight threshold for near steady state and relaxed threshold for transient operation. In the presented study, different transient triggers in a pipeline have been implemented to the dual threshold method in order to show the effect of transient thresholds on the reliability of the CPM models or the reduction in the number of false alarms. When the CPM model determines that a transient event is occurring, the imbalance threshold is increased to a pre-set higher value. The transient threshold will remain high until the transient event diminishes, then the thresholds will return to their original steady-state value after a pre-set wait period. This applies to each leak detection window and to each flow meter-to-flow meter section in the CPM model. Detailed information about the dual thresholds approach and the transient triggers is provided in the full paper. Results from the implementation of this method and the quantitative improvement of the CPM reliability and sensitivity will also be presented.

Autonomous Pathogen Detection System (APDS) NYC Spring 2005 Field Test Report May to July 2005

2005 ◽  
Author(s):  
J M Dzenitis ◽  
A J Makarewicz ◽  
D R Hadley ◽  
D M Gutierrez ◽  
T R Metz ◽  
...  
Keyword(s):  
Field Test ◽  
Pathogen Detection ◽  
Detection System ◽  
Test Report

METHODS OF ASSESSMENT THE LEVEL OF ENVIRONMENTAL AND ECONOMIC EFFECT DUE TO THE USING OF LOW-SPEED INDIVIDUAL VEHICLES, BY THE EXAMPLE OF THE TOWN OF SERPUKHOV

2019 ◽  
pp. 81-90
Author(s):  
Olga Leptiukhova ◽  
Marija Utkina
Keyword(s):  
Positive Impact ◽  
Economic Effect ◽  
Economic Benefits ◽  
Point Of View ◽  
Operational Parameters ◽  
Public Authorities ◽  
Low Speed ◽  
Standards Of Living ◽  
Complex Criterion ◽  
Electric Bicycle

For more than half a century bicycle transport demonstrates its effectiveness as one of the elements of the transport network of the city. Currently, vehicles with low-power motors such as electric bicycle, electric scooter, gyrometer, segway, wheelbarrow, scooter motor and others are gaining people's attention. These vehicles can be combined into a group of low-speed individual vehicles (hereinafter - NITS) with similar re-quirements for the operational parameters of urban infrastructure. From the urban point of view, the interest in NITC is that the number of its users has increased significantly in recent years. The article presents the results of a sociological survey of residents of Serpukhov, allowing to assess the current and potential readi-ness of the population to use NITC. The growing popularity of NITC has led to an increase in the environmen-tal and economic effect, which is manifested at a particular level of development of the movement on NITC. The ecological and economic effect of the use of NITC has an extremely positive impact on the improvement of the urban environment. This article provides a list of indicators that reflect the growth in the standards of living of society from movement by the NITC, and the calculation of one of them - the increase in entrepre-neurial activity on the streets with increased traffic to the NITC. Indicators are necessary for calculation of complex criterion of efficiency and safety of street network due to development of the movement by NITC. The result will allow public authorities authorized to make decisions on the strategy of transport policy of cities to quantify the ratio of economic benefits from the development of infrastructure of the NITC with the cost of its construction and operation.

scholarly journals Multipreconditioned GMRES for simulating stochastic automata networks

2018 ◽  
Vol 16 (1) ◽  
pp. 986-998
Author(s):  
Chun Wen ◽  
Ting-Zhu Huang ◽  
Xian-Ming Gu ◽  
Zhao-Li Shen ◽  
Hong-Fan Zhang ◽  
...  
Keyword(s):  
Steady State ◽  
Probability Distribution ◽  
Linear Systems ◽  
Iterative Methods ◽  
Communication Systems ◽  
Queueing Systems ◽  
Steady State Probability ◽  
Stochastic Automata ◽  
Automata Networks ◽  
Generator Matrices

AbstractStochastic Automata Networks (SANs) have a large amount of applications in modelling queueing systems and communication systems. To find the steady state probability distribution of the SANs, it often needs to solve linear systems which involve their generator matrices. However, some classical iterative methods such as the Jacobi and the Gauss-Seidel are inefficient due to the huge size of the generator matrices. In this paper, the multipreconditioned GMRES (MPGMRES) is considered by using two or more preconditioners simultaneously. Meanwhile, a selective version of the MPGMRES is presented to overcome the rapid increase of the storage requirements and make it practical. Numerical results on two models of SANs are reported to illustrate the effectiveness of these proposed methods.

Resistance to Outflow of Cerebrospinal Fluid Determined by Bolus Injection Technique and Constant Rate Steady State Infusion in Humans

Neurosurgery ◽  
1985 ◽  
Vol 16 (3) ◽  
pp. 336-340 ◽  
Author(s):  
Michael Kosteljanetz
Keyword(s):  
Cerebrospinal Fluid ◽  
Steady State ◽  
Bolus Injection ◽  
Point Of View ◽  
Injection Technique ◽  
Communicating Hydrocephalus ◽  
Constant Rate ◽  
High Degree ◽  
Infusion Technique

Abstract Two methods for the determination of resistance to the outflow of cerebrospinal fluid, the bolus injection technique and the constant rate steady state infusion technique, were compared. Thirty-two patients with a variety of intracranial diseases (usually communicating hydrocephalus) were studied. There was a high degree of correlation between the resistance values obtained with the two methods, but values based on the bolus injection technique were systematically and statistically significantly lower than those obtained with the constant rate infusion test. From a practical point of view. both methods were found to be applicable in a clinical setting.

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