Measurement Library

American School of Gas Measurement Technology Publications (1990)

American School of Gas Measurement Technologies

Application Of Low Power Flow Ccmputers
Author(s): Steve R. Cree
Abstract/Introduction:
Some eight years ago low powered flow ccmputers were introduced and required to prove themselves in three major areas: accuracy, reliability, and cost effectiveness. Electronic gas nfeasuretnent (EOyi) today is maturing in all three of these important aspects of use. Lets briefly look at each one. Accuracy, or irore accurately stated, acceptable accuracy is for the most part considered an achieved goal. (Extremely small ccmbined uncertainty numbers are available for correspondingly large price tags.) Most knowledgeable measurenent people have long recognized the improvements offered by once per second sampling of static line pressure, differential pressure and flowing temperature, coupled with once per second calculation of the flew extension, upon which all volume calculations should be based. The mathematical ccmparisons between circular chart integration methods and on site electronic methods of performing the basic flow equation are readily seen. They have been ccnfirmed repeatedly by various independent and corporate testing entities. The technology is being further advanced in several industry conmittees, nxjst notable of vrtiich is that of the API. Calculation methodology is currently under review with a focus on several issues, including sample rates, calculation intervals, data storage and audit, to name a few. The need for standards is apparent in every sector of our industry. A standard cubic foot of gas in an diio steel mill should be the same standard cubic foot of gas that was measured as it left a production platform in Louisiana. The vKrk, rfiile laborious, is growing vital as EC34 matures, and manufacturers continue to provide inter-corporate acceptable measurement information. As accuracy standards are elevated, so too will the flow ccmputers performance be elevated. New flow ccmputers for the new user will keep pace. For those vrtio have enjoyed the ccmpetitive advantages of flow computer units for years, retrofits and upgrades will be made available by nonctisolescence oriented manufacturers on a cost effective basis.
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Document ID: B7AA92C7

Gas Measurement By Insertion Turbine Flow Meters
Author(s): B. J. Kemperman
Abstract/Introduction:
There are a number of different types of insertion devices available for gas measurement. They include pitot tubes, vortex shedding meters, target meters, thermal dispersion meters and insertion turbine meters. What all these meters have in common is that (with the exception of the multiport averaging pitot tube) they make a measurement at one point In the pipeline cross section from which the total flow through the pipeline is inferred. Hence, if reasonably accurate measurement is required, it is important that such devices be inserted to a point in the pipeline where the prevailing flowing velocity is representative of the average of all velocities in the pipe. All insertion meters are averaging devices and must be viewed as such.
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Document ID: 4A4E1348

Field Experience With Composite Sampling Of Natural Gas
Author(s): Lonnie R, Grady
Abstract/Introduction:
For many years measurement technicians and measurement departments we re concerned only with MCF measurement. Gas composition was not critical and samples we re only occasionally taken. The gas industry changed and the MCF has been replaced by the MMBTU. Accurate analysis are only possible if representative samples of the flowing streams are collected. The best wav to do this is with a composite sampler. This paper addresses the selection, set up, operation and maintenance of composite samplers.
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Document ID: 6128A18A

Metering Research Facility Update
Author(s): Robert J. Mckee
Abstract/Introduction:
The natural gas industry within the United States produces, transports, and distributes some 17 trillion standard cubic feet of gas each year. In the process, virtually all gas is metered at least once, in meter sizes from 1 inch to 36 inches, at pressures above 1000 psi and below 1 psi, at temperatures below the ice point to around the boiling point, and with many different types of meters. Common types of meters include orifice and turbine meters for large flow applications, rotary and diaphragm meters for small flow applications, and ultrasonic, vortex, insertion, and other meters for special applications. It is essential to the gas industry that metering be accurate, reliable, and efficient over a wide range of conditions. The goal of the Gas Research Institute (GRl) in establishing the Metering Research Facility (MRF) is to improve the technology for gas flow measurement at field installations where the business of buying and selling gas takes place. i i Significant changes within the natural gas industry in recent years have placed increased emphasis on the need for accurate, reliable, and cost-efficient metering of natural gas. Through a series of industry workshops (Ref. 1), plans (Ref 2), and research programs (Refs. 3, 4, 5, 6, and 7), substantial improvements in metering technology have been developed. As metering needs are identified and improvements are implemented, it is necessary to evaluate the new technologies under carefully controlled field equivalent conditions. It is for the purposes of evaluating metering technology under field conditions, identifying and quantifying installation effects, providing independent accurate proving of meters, and developing criteria for acceptable, efficient, and practical metering that the MRF program has been developed.
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Document ID: 48A7DFB7

Water Vapor Determination And Effects On Gas Measurement
Author(s): Douglas E. Dodds
Abstract/Introduction:
The determination and the effect of water vapor on gas measurement is of Importance to the gas pipeline Industry because of the necessity for accurate gas measurement and for the maintenance of quality control. The following discussion covers typical methods which are used by the gas Industry for water vapor determination. Each of the dew point instruments discussed use a specific method for water vapor measurement, and all are designed for use as either portable or fixed location instrumentation. In addition to a discussion of the typical methods for water vapor determination, the effects of water vapor on gas volume and heating value measurement Is reviewed.
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Document ID: F003809A

Training Field Measurement Personnel
Author(s): E.D. Rusty Woomer, Jr., P.E.
Abstract/Introduction:
A practical, meaningful, and comprehensive training program in an appropriate learning environment is essential to fully develop the human resource. (1) This is particularly applicable to field measurement personnel in the natural gas industry. Natural gas measurement is a very specialized and technical field. With varying energy costs, improved and rapidly advancing technologies, and the changing business environment, the old process of on-thejoy training by passing doisTi tricks of the trade from one generation to the next is no longer affordable, efficient, or accurate. (1) This old process is inadequate in that it usually includes only routine functions on equipment (eg., inspection, testing, calibration, etc.). Non-routine functions on equipment (eg., theory of operation, troubleshooting, repair, etc.) are often ommitted from this old process. With this type of training and when on his own, the new measurement technician could be placed in precarious stituation resulting in unsafe conditions or loss of delivery service. Comprehensive training of field measurement personnel bridges this gap. Todays mcas-irement technician experiences an increase in responsibilities and must have a broader and more detailed knowledge of a vast variety of equipment. Comprehensive training of field measurement personnel becomes of paramount importance.
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Document ID: C8BBA1EF

H2S Detections And Determination
Author(s): Patrick J. Moore
Abstract/Introduction:
Hydrogen suifide is measured in the natural gas industry for three main reasons: 1) personal safety, 2) corrosion control, and 3) contractual obligations. Because hydrogen sulfide is very toxic, leaks must be detected rapidly to prevent injury and loss of life. Toxicity information based on the concentration of hydrogen sulfide and the time of exposure can be found in table 1, At low ppm/vol concentrations hydrogen sulfide has a rotten egg odor. As the concentration increases ones sense of smell is no longer useful for detecting the presence of hydrogen sulfide. Concentrations above 700 ppm/vol are almost instantaneously lethal. I Corrosion control and contractual obligations are interrelated. Contractual limits on the hydrogen sulfide concentration in natural gas exist to prevent excessive corrosion on a pipeline thus protecting the economic investment of the transmission company. Hydrogen sulfide reacts with the metal of the pipeline to generate molecular hydrogen. Because hydrogen is a very small molecule it can penetrate into the metal causing a loss of ductility. If there are tensile stresses on the metal, cracking can result. As the ductility of the metal decreases it becomes more susceptible to hydrogen attack. This form of corrosion is called hydrogen embhttiement. When the pipeline fails, product is lost creating a hazardous explosive condition.
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Document ID: B99EF71C

Fundamemtals Of Energy Determtnation
Author(s): P. E. Kizer
Abstract/Introduction:
Energy determination has beccme an integral part of the business of most of the transmission, distribution and production companies we know of today. Even Wall Street has given us a new name, Energy companies. Sane of us produce energy some transport energy but we are all in the energy business. Anyone with a teenager in his house is probably very aware of the energy hes paying for to heat water for those 30 minutes showers. It doesnt take too much snap to realize that the Singer gas meter outside the house doesnt ring up as many MCF if the gas has a higher heating value- It just doesnt take as many cubic feet to heat the hot water tank if the gas is 1090 BTU instead of 940 BTU per SCF. Take a look, for a monent, at vdiat happens at the burner tip. The follcwing is the exothermic reaction of methane and oxygen (80 to 95% of natural gas.
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Document ID: 0AA63386

Field Inspection And Calibration Of Measurement Instruments
Author(s): Daniel R. Fulton
Abstract/Introduction:
Weve been told over and over again that the meter is the cash register of the natural gas industry. Thats certainly true, and while the meter itself must adhere to certain accuracy and performance standards, the instrument used in conjunction with the meter should be thought of in the same manner. That is, overall accuracy of the meter set is dependent on how well the meter and the instrument are maintained. This paper outlines practical things to consider in the care and feeding of measurement instruments used with positive displacement and turbine meters. Three basic types of instruments will be covered: volume recorders, mechanical correctors and electronic correctors.
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Document ID: 496A616C

Design Of High Pressure Measuring Regulating Stations
Author(s): John m. Stephens
Abstract/Introduction:
Design of High Pressure Measuring Regulating Stations has been written about many times over the last 30 to 40 years. This paper presents a procedure to follow in designing a station using many of the developments which have evolved over these years. This procedure will be useful to first time designers as well as experienced designers. First, the functions of a Measuring Regulating Station should be reviewed. The primary function, as suggested by the title, is accurate measurement of flow. This is particularly true where the measurement is used as the basis of sales (custody transfer) of gas from one party to another. A second function is dependable regulation of high pressure gas from gathering systems or transmissions systems to lower pressure receiving systems.
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Document ID: 56E2553B

Problems In Offshore Gas Measurement Problems And Solutions Encountered In Qffshore Measurement
Author(s): Mikel Gaston
Abstract/Introduction:
The next 45 minutes will address some of the major problems and solution encounttered with gas measurment on offshore platforms in the Golf of Mexico. The presentation will also stress the importance of conpetent measuement personal in their roles in assuring that accurate measurement occurs. Sides thatidentiffy actual equipment installations, and logistics problem will be presented.
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Document ID: F4D9D853

Basic Principles Of Odorization
Author(s): J. T. Johnson
Abstract/Introduction:
The detection of natural gas leakage has long been a concern to the natural gas industry, but never more so than today. Increased pub lie awareness of safety and huge increases in the cost of product liability litigation has resulted in a greater focus on gas odorization. While odorization may be one of the smallest activities in the distribution of natural gas - NONE IS MORE IMPORTANT!!!
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Document ID: 84F6A984

Gauges Amd Deadweight Testers
Author(s): Michael S. Morrison
Abstract/Introduction:
The Eteadweight Gauge is the most accurate instrument available for the measuranent of pressures. Repeatabi readings with accuracies of 0.1% to .02% of measured pressure are obtainable. The device does not require recalibration unless the ccnxinents have excessive wear or weights are replaced. It is easily transported and set up in the field, requires minimum maintenance, and is simple to operate. Tripod mounting is available for mast instruments. With tlie addition of a pressure pump, valves, and pressure connections, the hydraulic Deadweight Gauge beccrnes a Deadweight Tester and can be used to calibrate pressure transducers and other, less-accurate pressure gauges. The pneumatic deadweight instruments are testers since they deliver aix at an accurate pressure usir an unregulated supply.
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Document ID: 24B039B0

Fundamental Principles Of Positive Displacement Meters
Author(s): Ed Stebbins
Abstract/Introduction:
In 1792 the process of manufacturing gas from coal was introduced in England. It was normal that the first gas meters were developed in England after the founding of the first gas company in London in 1808. In 1817 the first gas company was chartered in the city of Baltimore and gas was introduced commercially to the United States In those so called good ole days, meters were unknown and gas was sold more or less on an hourly basis by contract. Gas company inspectors would tour the city at night and rap on the walk or curbs outside of the homes to indicate to gas light customers that their contract time had expired and the lights were to be extinguished. If the customer ignored the warning, the inspector would turn the service off. This practice was then changed and the gas light customers were charged for the quantity of gas used based on the number, and possibly the size of light burners in the homes. Thus, the first gas meters developed were rated as Five Light, Ten- Light, etc. A gas light burner was based on a consumption of 6 cubic feet per hour.
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Document ID: 85B57183

Electronic Vs. Mechanical Correcting Devices
Author(s): James P. Micklos
Abstract/Introduction:
To understand the need for Mechanical or Electronic meter mounted correcting devices, one must understand the two essential units of measure of Natural Gas. These two units are: 1) Actual Cubic Foot (ACT) 2) Standard Cubic Foot fSCF) An Actual Cubic Foot would be the amount of gas that would be contained in an area that measures one foot in height, one foot in width, and one foot in depth. The measurements of this cube would be a constant, and would not chanere due to variations in pressure or temoerature. A Standard Cubic Foot, in contrast to an ACF., is measured under defined pressures and temneratures, which can varv from company to company.
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Document ID: 9CC37877

Application Of The Annubar Measurement In Gas Production And Processing
Author(s): Darnell Pebley
Abstract/Introduction:
Just because a flow measurement device is complex and/or expensive does not automatically mean that it is the best or most accurate. Oftentimes the most simple device is just as good and accurate and frequently even better. Economic pressure encourages the emergence of better all-around devices with greater reliability and accuracy. These and other factors have brought to the fluid flow measurement industry the Multiport Averaging Primary Flow Measurement Device. This refined version of the basic pitot tube, the same as the orifice and other head-type primaries, is based on the same standard hydraulic equation, continuity equation and Bernoullis Theorem. Thus, an extension and improvement of proven concepts and device makes available to the industry a primary flow measurement device which offers many benefits, including a simple design, with equal or better performance for fluid flow measurement and process control applications.
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Document ID: 42692137

Meter Selection For Various Load Requirements
Author(s): Anthony A. Schneemann
Abstract/Introduction:
As gas prices and cost of equipnent rise, the measurement of the product will increase in importance and it will be up to the measurement engineer to design the most efficient and econcmical meter station possible after all, the gas meter is known as the Cash Register of our business. The gas meter is used to measure and record the volume of gas through a gas line at existing conditions. There are two classes of meters, the positive displacement and the inferential. In positive displacement meters, the gas passes through a known volume. Inferential meters use physical facts related to velocity through a known area in order to derive volume measurements.
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Document ID: 2CA7F3E1

Fundamentals Of Orifice Metering
Author(s): m. J. Sergesketter
Abstract/Introduction:
This paper will provide information for use in selecting, applying, and checking the orifice metering system, with emphasis on gas measurement. The primary reference for mechanical tolerances of the orifice meter tube, plate holder and plate is American Gas Association Report No. 3, Orifice Metering of Natural Gas, published as ANSI/API Standard 2530. Much of this information is also published in a simpler, condensed format by orifice meter manufacturers. An excellent reference is Singer American Meter Division Handbook E-2. Meter tube and orifice plate information is contained in the Daniel Industries Flow Products catalog, and recommended installation practices for differential pressure instruments are contained in the ITT Barton Model 202E Flow Recorder Manual.
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Document ID: 88A17D4D

Fundamentals Of Gas Pressure Regulation
Author(s): Dean Splittgerber
Abstract/Introduction:
For all practical purposes, regulators used by the gas industry can be placed in either of two categories: I. Self Operated, or II. Pilot Operated. This categorizing of all regulators (plus all construction modifications) tends to be an oversimplification , but except ions are rare. Let s examine each of them closely. Self Operated Regulators An example of a self operated regulator is a spring opened valve directly opposed by a diaphragm assembly (Fig. 1). Gas, at Increasing downstream pressure, acts on the- diaphragm assembly to overcome the force of the spring, closing the valve. When downstream pressure falls, spring force Is greater than the force of the gas acting on the diaphragm, and the valve opens.
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Document ID: 79B52363

Overall Measurement Accuracy
Author(s): T . Dean G R A V Es
Abstract/Introduction:
To fully understand measurement accuracy, it is first necessary to look at the measurement process from a businesss and point. All business transactions, such as purchases,sales, transportation, exchanges, compression, and treating fees are based upon the gas volumes recorded during a predetermined time period. Company departments cannot complete their functions until volumes are reported. It is critical to the business process that these volumes be as accurate as possible. Many people have been striving for years to refine the measurement process to make it as accurateas possible. Unfortunately, there are still limitations to measurement accuracy. This paper will attempt to examine some of these limitations.
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Document ID: E46133B8

Fundamentals Of Gas Turbine Meters
Author(s): Richard H. Schieber
Abstract/Introduction:
The gas industry is fortunate in having a wide variety of measurement equipment available tp satisfy nearly every application need. Metering is no exception there are quite a few types of flowmeters in service. The bulk of gas measurement in North American, however, is handled by four basic types of meters diaphragm, rotary, turbine and orifice meters. As with any other choice, there are trade-offs to be made in selecting one type of meter over another in order to obtain the specific characteristics required for a specific application. Knowing the strengths and weaknesses of each type of meter is fundamental to the gas measurement engineer. This paper reviews the fundamental principles of turbine meters and compares them to diaphragm, rotary and orifice meters.
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Document ID: 7717FF15

Chart Editing And Integration Methods To Reduce Errors And Obtain Accurate Gas Volumes
Author(s): Gary P. Menzel
Abstract/Introduction:
The title assigned to us for this presentation may imply that we can define specific means to reduce errors and thereby irrprove measurement accuracy. Certainly we hope that our observations may contribute to that purpose but there is something unique about each coirpanies operations which prevents the application of a single procedural formula to everyone, and we will make no attempt to do so. However, a substantial part of our business is auditing gas purchasers, and we believe the statistics obtained in that process provide a representative cross section of the kinds of errors experienced by most chart departments. Defining a problem may be the first step toward its resolution, and it is that which we shall address in this report.
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Document ID: 7C633936

A New Concept In Data Communications
Author(s): Collin Cagle
Abstract/Introduction:
When compared to traditional methods such as microwave, leased line and radio, VSAT technology has been leading the advance in providing new means of connectivity for remote data collection applications. It has only been in the last three years that the application of VSAT (Very Small Aperture Terminal) networking to bidirectional data transmission has become widely accepted. Current estimates place the installed VSAT base at over 20,000 sites transmitting two-way data, and in come cases also supporting voice and even receiving one-way video. Possibly the market which initially exhibited the widest acceptance of satellite communication technology is the retail market. Corporations such as Wal-Mart, K-Mart, Target, Service Merchandise and Walgreens were some of the first to see the advantages offered by VSAT technology. Benefits associated with the operation of a satellite communication based network include lower recurring costs than terrestrial leased lines, predictable costs, multiple application support, high system availability, and freedom from dealing in a multiple vendor environment. Many, if not all, of these advantages also apply to most gas pipeline data networking requirements. Tenneco, ENRON, Columbia Gulf, El Paso Natural Gas, and Lone Star Gas are presently utilizing various implementations of VSAT technology to provide the data transport for monitoring and control of gas pipeline operations. Initially, some limited numbers of VSATs were selected for SCADA applications due to the simple fact that at some critical locations, there were no available terrestrial alternatives.
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Document ID: 26E754F2

Computer Applications To Chart Processing
Author(s): Ted J. Glazebrook
Abstract/Introduction:
Most of us are familiar with the orifice meter and the orifice chart. We recognize that the chart Is the key to determining the amount of gas used or produced. However, somewhere between the meter and the volume statement the information on the chart must be interpreted and calculated. It is important to bear in mind that the orifice chart does not contain all the information necessary for that final volume. Gas measurement would be quite simple if all we had to do was go into the field, read a little black box, assign a monetary value to the amount and then send a check or a bill.
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Document ID: 2AF93A00

Various Applications Of Telemetering In Gas Distribution
Author(s): James V. Vatzlavick
Abstract/Introduction:
One of the major problems inherent in a gas distribution system is the need for accurate real time information from remote sites to be available at a central control or dispatch facility. An obvious solution is the use of telemetering, which is the remote measuring of physical variables, such as pressure, differential, temperature, pulse rate, or flow rate. Telemetering provides accurate on-demand information relevent to the operation of a gas distribution system. Historically, telephone lines have been the most popular method. D.C. (hardwire) telephone circuits or Tone (voice grade) telephone circuits can be used. However, new technology has made the use of radio frequency channels a viable option as well.
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Document ID: 1202163D

Fundamentals Of Orifice Recorders
Author(s): Kenneth P. Cessac
Abstract/Introduction:
This paper will provide information for use in selecting an orifice recorder. What is an orifice recorder or sometimes referred to as an orifice meter? The term orifice meter is used to mean everything from the orifice meter gauge recorder to the entire meter station. The American Gas Association defines the orifice meter as the complete measuring unit comprised of primary and secondary elelments. The orifice meter tube and connection fittings are considered the primary measuring element.
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Document ID: F076F737

Determination Of Calorific Values Of Natural Gas By Combustion
Author(s): Richard L. Howard
Abstract/Introduction:
Calorific value is a way of defining a quantity of gas in terms of heat per unit volume. In the U.S.A., the units most often used are British Thermal Unit (BTU) and cubic foot (SCF). A generally accepted definition of the BTU is the quantity of heat required to raise the temperature of one pound of water one degree Fahrenheit at or near its point of maximum density. There are currently available in the U.S.A. two instruments which determine the heating value of natural gas by burning the gas.
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Document ID: 32C102AE

Turbulence And Its Effect In Measuring And Regulating Stations
Author(s): Mike Mckay
Abstract/Introduction:
For several years gas men have been giving more thought to aerodynamic turbulence within their pipeline systems and, in particular, the turbulence that is a result of pressure regulation, Considering the noise from a measurement or regulating station, it is generally conceded that measurement facilities alone will rarely be a major source of noise, since we can design the pipe to give a desired and normally tranquil velocity. On the other hand, we must expect that in a regulator station control of the gas velocity is possible only up to the inlet side of an active regulator. At the point of regulation within the regulator body, the velocity of the gas may be expected to increase greatly, perhaps up to sonic velocity. Now the question becomes, What is the best way to handle gas when it is traveling at high velocities?
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Document ID: 123EC2C4

Basic Electronics For Field Measurement
Author(s): Fred Debusk
Abstract/Introduction:
Recent events in the transportation of natural gas have created a strong interest in electronic measurement. Gas measurement personnel are use to dealing with the mechanical aspect of gas measurement, but some orientation is necessary to properly understand the electronic aspect of gas measurement.
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Document ID: 83B45D90

From Pen Tip To Volume Statement
Author(s): Philip C. Morris
Abstract/Introduction:
Accurate and reliable gas measurement depends on a combination of efforts and investments. In large companies these efforts include the legal department for contracts, the engineering department for specifying equipment and the purchasing department for buying that equipment. The field services department must then install the equipment. By the time the meter pen tip records the first gas production, there will have been literally dozens of people involved, from land men and geologists to drilling and production people. An investment of thousands of dollars will also have occurred. Regardless of company size there is always a major investment of time and money before
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Document ID: C18A8AC7

New Ideas In Measurement Real Time -- A Measurement Perspective
Author(s): William E. Wickman
Abstract/Introduction:
The natural gas pipeline industry working environment has changed dramatically over the last decade. The complexity of transactions handled today in the natural gas industry has increased phenomenally and the means of handling gas both physically and contractually is in a state of tremendous flux. Essentially New Ideas In Measurement have not been manifest in the equipment employed to measure and monitor natural gas but rather in the strategies employed to satisfy the demands of our rapidly changing environment not applied sciences, but rather conceptual theologies. Hence, we will not look at the technological strides made in new and exotic equipment, but at the concept of how companies are grappling with the conceptual changes in this new era of the natural gas pipeline industry.
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Document ID: A3A56008

Field Testing By Transfer Proving
Author(s): Ronald L. Cawlfield
Abstract/Introduction:
There currently exists three types of field proving equipment for testing large diaphram, rotary and turbine meters. The three types are low pressure, critical flow arid transfer provers. Both low pressure and transfer proving are generally performed with air and at a vacuum (or in the case of low pressure proving optionally at a slight positive pressure) while critical flow proving is done with gas at 15 #s plus. For transfer proving, the prover is located on the outlet side of the meter being tested, as it is for critical flow proving.
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Document ID: 49D4CF5B

Regulatory Commission Safety Evaluation And Training
Author(s): Carl Nordstrand, P.E.
Abstract/Introduction:
In 1970, the Railroad Commission of Texas began enforcing the Federal Natural Gas Pipeline Safety Act of 1968. These standards are published in the Federal Register, (49 CFR 192). A copy of these rules along with additional State safety rules can be obtained from the Transportation/ Gas Utilities Division of the Railroad Commission of Texas in Austin. Actually Texas has been regulating gas suppliers since 1920 when the legislature passed the Cox Act placing gas pipeline operators under the control of the Railroad Commission of Texas for rate determination.
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Document ID: F656C14D

Economics And Justification For Electronics In Gas Measurement
Author(s): Brad Merlie
Abstract/Introduction:
In recent years, an increasing number of natural gas production, transmission, and distribution companies have begun to move away from the time honored means of recording gas flow information on paper charts. While the heart of most custody transfer measurement installations remains the meter tube/orifice plate combination, the use of microprocessor based electronic flow measurement (EFM) devices to record metering data is increasing at a rapid rate. These devices are being used to gather flow data on site, and calculate and store volumes based on AGA-3, AGA-7, NX- 19, and/or AGA-8 equations. Depending on the manufacturer, data can be stored at intervals from one minute to one hour and as much as one year of hourly data can be maintained in the EFM devices memory.
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Document ID: 06466814

Mikeing And Inspecting Meter Tubes
Author(s): Lonnie R. Grady
Abstract/Introduction:
Gas prices are once again on the slide. Most companies, both producers and transporters, are looking for ways of cutting overhead. Measurement is an area that is often one of the first to suffer. I agree that cost consciousness is important and some cuts in measurement services may be justified. An area that should not be cut is the inspection of meter tubes. This paper will attempt to present the methods used to insure that meter tubes meet ANSI/API 2530 (AGA3) requirements.
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Document ID: ABD9C124

Chart Auditing
Author(s): Bonnie L. West
Abstract/Introduction:
Columbia Gulf audits not only stations that are input points directly into our own pipeline, but offsystem locations for Columbia Gas Transmission Corporation as well. These locations are audited on a monthly, semi-annual or annual basis. The criteria, set up by management, for determining audit priority are as follows: 1) Locations where Columbias share of gas is 25 MMcfd or greater are audited monthly. 2) Locations where Columbias share of gas is 2 MMcfd - 25 MMcfd are audited semi-annually. 3) Locations less than 2 MMcfd are audited annually. All locations are reviewed twice a year and an update is done to conform to the above criteria. At present, we are auditing 12 locations monthly, 30 semi-annually and 200 annually.
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Document ID: 5F39A7A9

Orifice Meter Testing
Author(s): Gail Ledbetter
Abstract/Introduction:
In orifice meter testing there are three primary elements which must be observed to assure the accuracy of the orifice meter. They are the meter tube, the orifice plate and the orifice meter. Each element has criteria which must be met to conform to the AGA Report #3. In the following paragraphs we will look at each element as it pertains to testing an orifice meter.
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Document ID: BC3C64D8

Determination Of Specific Gravity By Various Methods
Author(s): E. D. Woomer, Jr., P.E.
Abstract/Introduction:
This paper deals with the determination of specific gravity via various methods and pieces of equipment. Also covered are definitions, relationships, and effects of specific gravity. The information presented herewith is applicable to United Gas Pipe Line Co. and conforms to accepted standards of the natural gas transmission industry.
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Document ID: 3BB30CB7

Electronic Chart Scanning And Related Equipment
Author(s): James L. Hamlin
Abstract/Introduction:
With the advent of on-site electronic flow computers we in the chart processing end of our industry are sometimes overlooked by management when attempts are made to modernize our chart processing operations. But, as the cost versus benefit factors rise to the surface, this writer believes modernizing the chart processing departments will provide a much more economical and accurate result than on-site EFM devices - with one very important plus - the chart provides an excellent audit trail. In fact, the measurement chart is the only audit which can be re-calculated and reevaluated time and time again.
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Document ID: 786A4565

Designing An Acoustic Filter To Reduce Pulsations In Metering Applications
Author(s): Larry E. Blodgelt
Abstract/Introduction:
There is a definite need on many occasions to decrease pulsations in the pipmg associated with orifice meters. This task has been the primary domain of acoustical piping designers who have had both theoretical and practical field experience in such areas. And it is always best to take advantage of such expertise when it is available. Most filters designed by novices are not effective and are costly to operate because of pressure drop losses. There are many small compressors such as well-head gathering compressors that cannot justify the cost of a thorough acoustic analysis in order to protect the nearby orifice meter from excessive pulsations and accompanying square root error. This paper will make an effort to demonstrate design procedures related to a specific type of acoustic filter to be used to reduce pulsations in metering applications. The specific filter is a symmetrical in-line low-pass filter.
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Document ID: 51E6B2A7

Effects On Entrained Liquid On Orifice Measurement
Author(s): C. V. Mooney
Abstract/Introduction:
In the measurement of natural gas in field operations using the conventional orifice meter, all of the factors used in the calculation of flow are based on the assumption that the gas is dry. This condition is rarely the case in field measurements. The A.G.A. Committee Report No. 3, (1), does not give any information or data regarding the effect water and/or distillate may have upon gas measurement by the orifice meter. It vas in this area of gas measurement that graduate-engineering students at Texas A&I University, Kingsville, Texas have conducted research operation in the laboratory and in the field.
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Document ID: 3ED68E64

Electronic Chart Integrators
Author(s): Bryan Billeaud
Abstract/Introduction:
In the natural gas industry, measurement and calculation of gas volumes have long been accomplished through the use of orifice meter chart records. Machines which make the calculation from these records are a common sight to most companies involved in gas measurement. Electronic equipment, especially, have brought about substantial improvement to measurement and calculations due to their ever increasing speed, accuracy and mathematical abilities.
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Document ID: AE48E8A2

Operational Procedures Of Electronic Chart Processor
Author(s): Chuck Gray
Abstract/Introduction:
The UGC Chart Processor is a microprocessor based system designed to translate orifice meter chart records into accurate billlng-compatlbie data of integrated flow (chart extension), flow time and average pressure. It will handle American (Westcott) and Foxboro charts as the pens can be mounted so as to pivot In the same geometric paths as the recording pens of these types of meters. As an option, the Chart Processor can be fitted with pen mounts for Taylor and/or Rockwell charts. The operator directs the pens to follow the records by moving the trace handles as the chart rotates. The rotational speed of the chart table is governed by a variable foot control. The chart is secured to the chart table so its rotation and the motion of the pens by the operator simulate the actions in the recording meter.
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Document ID: BDC3F469

Spot Sampling Techniques
Author(s): Jerry Bernos
Abstract/Introduction:
In 1978 the United States Congress passed the Natural Gas Policy Act. This legislation required that natural gas be priced according to its energy content rather than by volume alone. At the same time, the economics of the natural gas industry caused natural gas prices to soar. These two factors resulted in a vast increase in the demand for accurate analyses of natural gas systems. Since it was not economically feasible to place analytical instruments at each and every location requiring BTU determinations, a corresponding increase occurred in the need to obtain spot samples of these systems. This paper is intended to present the problems that arise in spot sampling and to introduce the industry accepted methods which can overcome these problems.
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Document ID: 65DC2434

Gas Contract Iwterpretation
Author(s): John D. Howard
Abstract/Introduction:
As measurement people we will look at various contractual statements that may or may not be in every contract. I am not an attorney but remember this, most attorneys are not measurement people. We - will mean measurement people in this discussion. We will find many areas in the contract that do not pertain to our responsibilities In fulfilling this contract. Lets look at the specifics that we are concerned with:
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Document ID: 57A35C88

Fundamental Gas Laws
Author(s): Rogers G. Thompson
Abstract/Introduction:
We as gas measurement people are concerned with gas laws. To become proficient in all phases of gas measurement, one must fully understand what natural gas is and the theory of its properties. The theories about natural gas properties are the gas laws, and their application is essential to gas measurement. Quantities of natural gas for custody transfer are stated in terms of standard cubic feet. To arrive at standard cubic feet from actual flowing conditions requires application of correction factors that are defined by the gas laws.
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Document ID: BC45738C

Troubleshooting Glycol Dehydrators
Author(s): Don Ballard
Abstract/Introduction:
The ability to quickly identify and eliminate costly operating problems can frequently save thousands of dollars. There are some troubleshooting resources which are required to quickly solve problems and to optimize the glycol unit to achieve an efficient and economical operation. The resources should include a good understanding of glycol dehydration fundamentals, an accurate flow diagram of the system, vessel schematics, current operating conditions and periodic glycol analyses. With this useful information, a troubleshooter can do an excellent job. Here are some common problems that occur in glycol units and some helpful hints to solve the problems.
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Document ID: 6F6F5CB8

Design Considerations For Orifice Meter Tubes
Author(s): Ray Kendrick
Abstract/Introduction:
What 1s a meter tube? The most widely used standard (ANSI/API 2530) describes a meter tube (Figure 1) as the straight upstream and downstream pipe of the same diameter, including straightening vanes (if used), the orifice holding device (with pressure taps) and the orifice plate.
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Document ID: D1422A3A

Field Testing Of High Volume Gas Turbine Meters
Author(s): Jim Beeson
Abstract/Introduction:
Arkla Energy Resources developed and ojunrently uses a mobile gas turbine meter proving system on 3 thru 12 gas turbine meters at station sites under actual operating conditions. It combines technology from liquid turbine meter provers with new ideas that specifically apply to gas measurement. The prover also contains a gas chromatograph which is used in actual mass flow coirputations. This system has several advantages over earlier methods of proving gas turbine meters. Arkla previously proved its larger turbine meters, capable of 60,000 ACFH, with a Roots transfer prover capable of only 10,000 ACFH. This meant that the provings were at or near increments on the proving curve where the K-factor might be in error for the turbine meters normal flow rate. With the sonic nozzle prover Arkla can now prove a turbine meter at the rate it is actually flowing.
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Document ID: 4970E627

Instrumentation And Volume Calculation For P.D. And Turbine Meters
Author(s): Giles m. Crabtree
Abstract/Introduction:
When metering large volumes of gas at elevated pressures using rotary, or turbine meters, it is customary to supplement the meter with an instrument which will correct the metered volume to base conditions. This paper will refer to the installation and maintenance procedures of the Continuous Integrating, Base Pressure and Base Volume Indexes. A Base Pressure Continuous Integrator is a mechanical instrument which by means of a pressure sensing element, a rotating disc, ring and shaft assembly, continuously applies the pressure factor to the metered volume as the gas is flowing. See Illustration Number 1.
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Document ID: 3C38044B

Calculation Of Gas Lost Due To Breaks, Ruptures Or Third Party Damage
Author(s): E.G. Keramerer
Abstract/Introduction:
In order to be consistent In my companys methods of gas loss calculation I recently developed the following information which I hope will also be useful to anyone who has experienced problems when gas volumes need to be calculated due to pipeline ruptures, blowdowns, and purges. The formulas used in this report were derived from the Weymouth equation and critical flow concepts. It is noted that at any rupture, the biggest loss is usually due to the accidental blowdown (occurs before any block valves are closed), followed by drain loss (blowdown which begins after block valves are closed), and last is purge loss which is the smallest part of the total loss as it is done for a relatively short time at low pressure. So the total loss in an accidental pipeline rupture as defined by this paper, consists of blowdown loss plus drain loss plus purge loss.
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Document ID: 78E76EB2

Unaccounted-For Gas
Author(s): Christopher J. Glaeser
Abstract/Introduction:
Unaccounted-for gas is defined as the difference between the amount of gas purchased and the amount of gas sold. This figure is most commonly described as a percentage of the gas purchased percent unaccounted-for gas. The unaccounted-for figure can be either a positive number (more gas was purchased than sold) or a negative number (more gas was sold than purchased). in either case, it is important to determine what factors are contfibuling to the unaccounted-for gas and eliminate them. The reasons are economics and safety. Economically, unaccounted-for gas represents lost revenues that are nol recoverable. It is gas purchased from a supplier but not sold to a customer (positive unaccounted-for gas). The other reason that we are interested in unaccounted-for gas is public safety. Leakage, third party damage and gas theft contribute to unaccounted-for gas that can effect the safety of our customers.
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Document ID: DF70E48D

Light Hydrocarbon Measurement
Author(s): Gregory C. Riddick
Abstract/Introduction:
Light hydrocarbon liquids, for purposes of this paper, consist predominately of the following components: ethane, propane, butanes, pentanes, hexanes and heavier paraffinic hydrocarbons. The liquid may be ccMiiposed of a large percentage of one of these types of molecules, as in the case of specification grade propane product, or they may be a mixture of all these molecules, as in the case of unfractionated natural gas liquid (NGL) mix. Additionally, other components, such as olefins and contaminants, are also in the liquids, but they are present in a lesser percentage. Measurement of light hydrocarbon liquids is more difficult than the measurement of crude oils and refined products for a number of reasons. First, they are of low viscosity and have very poor lubricating properties. Secondly, the jiiysical properties vary widely as their composition varies. Additionally, their physical properties are dramatically different under different temperature and pressure conditions.
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Document ID: 965AB897

Fundamentals Of Rotary Metering
Author(s): James B. Bennett
Abstract/Introduction:
The first positive displacement rotary gas meters were built in 1920 by the PH & FM ROOTS Company and the Connersville Blower Company, both located in Connersville, Indiana. In 1966, this gas meter operation was renamed Dresser Measurement Division. However, these rotary meters today are still known as ROOTS Meters. Rockwell International entered the market in the early 1960s with a rotating vane design known as the ROTO-Seal Meter, and in the late 1960s Singers American Meter Company introduced still another rotating design known as the CVM gas meter. There are several foreign competitors who also manufacture a lobed rotary meter. The operating principles for each of these three meters are depicted and explained in Exhibit #1.
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Document ID: 92C68E2F

Pulsation Effects On Orifice Metering Considering Primary And Secondary Elements
Author(s): Robert J. Mckee
Abstract/Introduction:
The use of orifices for commercial flow measurement has a long history dating back more than 50 years. Orifices are extensively used in the United States natural gas, petroleum, and petrochemical industries and are important as one of the most practical ways to meter large volumes of gas flow. These meters are very reliable and cost effective and if properly used, can be relied upon to give accurate results. Proper use normally requires the steady flows for which orifices were intended and for which the orifice coefficients were developed. In actual field installations, flow is often not steady but subject to the periodic changes in pressure and velocity that are referred to as pulsations. Pulsations can be caused by compressors, pressure regulators, control valves, fluctuating loads, or by flow-induced phenomena within the piping. It is known and well recognized that pulsations cause errors in orifice meter results. In fact, A.G.A. Report No. 3 on Orifice Metering of Natural Gas, which is also ANSI/API 2530, clearly states that: Reliable measurements of a gas flow with an orifice cannot be obtained when appreciable pulsations . . . are present at the measurement point.
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Document ID: 3637AAD1

Operation Of On Line Gas Chromatography
Author(s): Lou Cox
Abstract/Introduction:
Gas chromatography is a physical method of separation where the components to be separated are distributed between two phases - a stationary bed of large surface area, and a fluid that moves through the stationary bed. A gas or vaporized liquid mixture is physically separated into its individual components through this stationary bed.
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Document ID: 75F2DAC2


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