Measurement Library

American School of Gas Measurement Technology Publications (1991)

American School of Gas Measurement Technologies

Fundamentals Of Gas Pressure Regulation
Author(s): Norman Tingley
Abstract/Introduction:
Due to the nature of the gas distribution system, the development of the gas regulator has grown. There are at least two reasons why gas regulators have come to be. Efficient distribution of natural gas in gas lines requires the pumping up of the gas to high levels (500 to 1400 psig, typical). On the other hand, for reasons of convenience, normal gas appliance design, safety features, and metering considerations the gas pressure at the end user is reduced (typically to l/A psig).
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Document ID: 591535D0

Fundamentals Of Orifice Metering
Author(s): Larry Irving, Jr.
Abstract/Introduction:
This paper will provide information for use in the understanding of the fundamentals of orifice metering with an emphasis on gas measurement. The reference for specific mechanical tolerances is the American Gas Association Report No. 3, Orifice Metering of Natural Gas, published as ANSI/API standard 2530. The intent of this paper is to provide an overview of the various parts that comprise orifice metering and how these parts work together to form a meter installation.
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Document ID: 6A4EE14C

Instrumentation And Volume Calculations For Pd And Turbine Meters
Author(s): C. Wayne Burrell
Abstract/Introduction:
Natural gas distribution companies use a variety of instruments to define uncorrected varibles to achieve corrected volumes of gas that passes through PD and Turbine meters. 1. Compensated Indexes 2. Fixed Factors 3. Volume Recorders i 4. Mechanical Volume Correctors 5. Electronic Volume Correctors 6. Data Collection and Communication Generally speaking, LDCs only use compensating indexes on residential and or commercial applications where the loads are too small to justify the cost of more expensive instruments. These meters can be internally temperature compensated types and when used with a good pressure regulator metering gas at elevated pressures a pressure factor can be achieved that would be acceptable accuracy-wise. Some do not use the compensated index because there is normally a built-in error in the index. Thus, you must compensate the compensating index. Rather than do this, most just plug the factor into the billing machine and use the standard index.
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Document ID: 3E0C640F

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 inprove measurement accuracy. Certainly we hope that our observations may contribute to that purpose but there is something unique about each companies operations which prevents the application of a single procedural formula to everyone, and we will make no atteirpt 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. Our study included charts from over 100 gas purchasers. proximately 3.5% of all stations audited by Coastal Flow during the one year period ending September 30, 1989 contained errors which were resolved by agreement between the affected parties. For the five years we have been keeping these statistics, the incidence of error has always been between 3% and 4%.
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Document ID: C470EE94

Operations Of On-Line Gas Chromatography
Author(s): F.D. Martin
Abstract/Introduction:
On-line gas chromatography is a special kind of GC that can be considered a concentration transmitter. The process is sensed and a process compatible signal is presented to a trend recorder, controller, DCS, or other device that is proportional to component concentration. An example would be 4-20 ma signal input to a cascade steam controller to control distillation column temperature based upon I-C4 concentration in the bottoms sample. It is a complex transmitter, but provides very important information for process monitoring and control. A process gas chromatograph is different from a laboratory GC in enclosure, automation, and output. It is designed for petro-chemical lnplant use. Calibration and sampling considerations are also somewhat different. Emphasis will be placed on these differences. The on-line or process gas chromatograph must provide data 24 hours a day, 7 days a week. all operations must be automated by the GC programmer. Some of these are listed in Figure 1.
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Document ID: 467492BA

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: F79754E4

Basic Electronics For Field Measurement
Author(s): D. R. Dave() Looper
Abstract/Introduction:
This paper hopefully affords readers a broad brushed overview of electronics basics and how they are utilized in todays increasingly technical world. There are references to established formulas and relationships as well as a discussion on some state-of-the-art technology. The latter is often short changed in these types of presentations and it seemed a good idea to hit some of these basics, too. Perhaps the discussion herein will prove at least informative to those that have limited exposure to computer technology. This understanding is more and more vital to the successful implementation of computerized measurement and automation systems in our Natural Gas Industry.
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Document ID: 08698358

Solar Powered Satellite Computers
Author(s): Charles R. Porter, Jr.
Abstract/Introduction:
Gas measurement in remote areas can be difficult and expensive. Yet it is imperative we are in touch with our production volumes, routes, and general disposition. With the improvements in solar power and new satellite technology, we now can receive information from even the most challenging remote location.
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Document ID: F509D283

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 Che best way to handle gas when it is traveling at high velocities? Notice that there will be two distinct sources for noise in a regulator station. One is the control valve Itself and the other is from the piping downstream of the control valve. In order to develop a good basic knowledge of turbulence, it becomes necessary to understand the mechanics of it. Turbulence is the part of the flowing medium that is traveling in a direction that is in opposition to the main flow path. For instance, a vortex is a flow pattern that is sometimes perpendicular to Che main path, sometimes turned back toward the source and ac other times impinging directly into the main path. If you think that this can cause trouble, you are correct. Impingement of gas traveling at high speed is another problem and an additional source of noise.
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Document ID: 9DF2B2B3

Basic Electronics For Field Measurement
Author(s): D. R. Dave() Looper
Abstract/Introduction:
This paper hopefully affords readers a broad brushed overview of electronics basics and how they are utilized in todays increasingly technical world. There are references to established formulas and relationships as well as a diacussion on some state-of-the-art technology. The latter is often short changed in these types of presentations and it seemed a good idea to hit some of these basics, too. Perhaps the discussion herein will prove at least informative to those that have limited exposure to computer technology. This understanding is more and more vital to the successful implementation of computerized measurement and automation systems in our Natural Gas Industry.
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Document ID: 809DC3BB

Funuamental 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: 6F7363E8

Overall Measurement Accuracy
Author(s): T. Dean Graves
Abstract/Introduction:
To fully understand measurement accuracy , it is first necessary to look at the measurement process from a business stand 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 accurate as 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: 7361438D

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 statement is particularly applicable to field measurement personnel in the natural gas industry. Natural gas measurement is a very specialized and technical field. Todays measurement technician 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: A714423F

Fundamentals Of Orifice Recorders
Author(s): Kenneth P. Cessac
Abstract/Introduction:
This paper wil 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 everyting form th 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 elements. The orifice meter tube and connection fittings are considered the primary measuring element. The instruments used to record the variables if the stream flowing through the orifice tube are considered the secondary ekements. Some of the secondary devices used with orifice measurment are differential pressur recorder, static pressure recorder, flowing temperature recorder, and any other required recordings such as specific gravity and heating value. Orifice measurment is based on accurately measuring a pressure drop which occurs when gas is flowing througjh a line passes through a restriction in the line. In order for the same volume of gas to pass througjh the rastriction a pressure drop across the restriction must occur. This pressure drop or differential pressure is proportional to the gas velocity and when combined with other known factors the gas volume can be calculated.
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Document ID: 3461F3B8

Chart Audits
Author(s): Mildred Moore
Abstract/Introduction:
The subject of accuracy in gas measurement remains a topic of discussion at all levels of corporate management, training schools, and throughout the gas industry. The need for preciseness begins with a complete overview from the meter installation and ends with the correct billing of the customer/producer. This presentation deals primarily with the foreign (external) approach. Although, a similarity exists between the external and Internal chart audits, most companies depend on the expertise of its own employees for internal error control. The chart audit not only implies volume accuracy, but it also includes the implementation of company policies and standards as a guideline. Because auditing can involve many different ententes such as sales, receipts, exchanges, or transports the need for specific company procedures and government regulations in the manipulation of the data becomes an important tool. For example, it is imperative In the initial audit analysis that the type of transaction be handled according to the companys contract. Another significant document in assisting an auditor or accountant includes a detailed Inventory Report which provides all the information about the meter station such as: meter type, (positive, turbine, or orifice), its location, plate size, and other pertinent data. This report and related informa:ion play a crucial role in the verification of the meter stations physical components and further contribute to the accuracy in the billing cycle. Not only can the implementation of policies and standards aid a very tedious and difficult task, but it also can bring into focus creditablllty between the producer and customer.
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Document ID: 1CD73A2B

Meter Selection For Various Load Requirements
Author(s): Frank Brown
Abstract/Introduction:
As pipeline companies business move more toward gas transport, the proper meter is of the utmost importance. The pressure is on the measurement engineer to design the most effective, yet economical station possible. It is essential that equipment is capable of operating in modes to meet the rapid changes in the market. As we go through various types of primary flow measurement devices and discuss each, you will see that there is a variation in complexity. However, this is not an indication as to which is the best or most accurate. We often tend to equate complexity with accuracy, but when it comes to gas metering devices this is not always the case. Let us take a look at some of the metering methods and devices used in measuring gas flow. They are as follows: * Positive Displacement * Orifice * Turbine * Venturi * Flow Nozzle * Annubar
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Document ID: E5A6AB4A

Pulsation Reduction
Author(s): Stephen R. English
Abstract/Introduction:
Pulsation has long been recognized as potentially creating significant errors in gas measurement. Pulsation induced error is most commonly associated with the orifice meter. However, it is not a problem restricted solely to this type of primary measurement device. The turbine meter, vortex shedLiiiig metef, and diaphragm meter are all subject to errors induced by pulsating flow. Tlie value placed on the gas passing through these purchase aiid sales meters makes accurate measurement imperative. It is important to understand, predict, measure, and control pulsationss if the measurement is to have any validity.
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Document ID: 5D650C41

Field Inspections And Calibration Of Measurement Instruments
Author(s): Bill D. Frachiseur
Abstract/Introduction:
Measurement instruments have gone through a significant change in recent years. Not only are we expected to maintain measurement instruments as simple as gauges and thermometers, but also flow computers. Fluctuating gas prices, unacceptable unaccounted for gas extremes, and limited quantities of gas to be transported and/or sold, have distribution companies scrambling to increase revenues. They have little control over gas pricing, but strive to insure that every MCF that passes through their system is accounted for by paying closer attention to gas measurement accuracy. The most commonly used metering devices, positive displacement, turbine, and orifice metering would be self sufficient if they always worked at base pressure and base temperature conditions. This is not the case, hence the wide variety of correcting devices.
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Document ID: E227D340

Determination Of Specific Gravity By Various Methods
Author(s): E. D. Rusty 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: 65F9E947

Unaccounted-For Gas
Author(s): Christopher J. Glaeser
Abstract/Introduction:
Unaccounted-tor 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 percenlage of the gas purchased percent unaccounted-for gas. Example: Unaccounted-for Gas Gas Purchased Gas Sold Unaccounted-for Gas 50,000 cubic feet - 45,000 cubic feet 5,000 cubic feet Percent Unaccounted-for Gas Unaccounted-for Gas 5,000 cubic feet Gas Purchased 50,000 cubic feet X 100 10% 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 contributing to the unaccounted-for gas and eliminate them. The reasons are economics and safety. Economically, unaccounted-for gas represents lost revenues thai are not 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-tor gas that can effect the safety of our customers.
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Document ID: C9446DF1

Field Testing By Transfer Proving
Author(s): Carlos T. Ponce
Abstract/Introduction:
There currently exists three types of field proving equipment for testing large diaphram, rotary emd turbine Meters. The three types are low pressure, critical flow and 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 #8 plus. For transfer proving, the prover is located on the outlet side of the meter being tested, as it is for critical flow proving. However, it may be located upstream or downstream for low pressure proving. Similarly when low pressure prov ing the blower can be on the inlet or outlet (but always on the opposite end from the prover). The blower location for transfer proving is not only downstreeim of the meter but also downstream of the prover. In critical flow proving a blower is not necessary.
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Document ID: B347FAF0

Fundamental Principles Of Rotary Positive Displacement Meters
Author(s): Rick Gregorczyk
Abstract/Introduction:
In North America, almost all natural gas is measured by four types of meters: Diaphragm, Rotary, Turbine and Orifice. Diaphragm and Rotary meters are classified as positive displacement meters, They measure gas by alternately filling and emptying measurement chambers of a fixed and known volume. Rotary meters have been in use for over 60 years in the gas industry. The first meters were foot mounted and constructed of cast iron. In the past 20 years, the majority of Rotary meters put in service have been constructed of aluminum and are line mounted, The Rotary meters long-term track record of reliability, accuracy and versatility has made it useful in nearly all aspects of gas measurement. Applications for rotary meters include: at the wellhead in gas production and processing, in compressor stations for transmission, and for commercial and industrial distribution measurement.
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Document ID: 8409C78E

Field Experience With Composite Sampling Of Natural Gas
Author(s): Lonnie R. Grady
Abstract/Introduction:
For many years measurement technicians and measurement depart ments we re concerned only with MCF measurement. Gas composition was not critical and samples were 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 samp1ers.
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Document ID: D9621AE9

AGA 3 Calculations, Old Vs New
Author(s): AGA 3 Calculations, Old Vs New
Abstract/Introduction:
A.G.A. Report No. 3, Orifice Metering of Natural Gas and Other Related Hydrocarbon Fluids, officially published as ANSI/API 2530, is the standard used in the natural gas industry which specifies the installation requirements and flow rate calculations for orifice meters. The 1990/91 revision to this standard has many significant improvements which will impact gas distribution and transmission companies. The new orifice coefficient equations, new calculation procedures, and revised meter installation specifications substantially reduce the measurement uncertainty associated with orifice meters. Companies will need to revise their related inhouse documents and volume calculation software. The purpose of this paper is to inform the users of orifice meters that the A.G.A. Report No. 3 standard has been changed in a significant way, and to alert them on what the impacts may be on their operation. The 1990/91 revision includes the biggest changes that have been incorporated into this standard in 55 years!
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Document ID: E222E13B

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 problem.
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Document ID: 4434A865

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 jlack box, assign a monetary value to the amount and then send a check or a bill. Unfortunately, there is no single instrument which can measure all of the different types of information needed to calculate a volume or an MMBTU value. Some of the information which is required and the associated instruments used to capture that data.
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Document ID: D0F082A8

Periodic Inspection Of District Regulators S Relief Valves
Author(s): George L. Bell, Sr.
Abstract/Introduction:
Inspections of district regulating stations and overpressure protection devices are essential in complying with Federal and state Regulations. District regulators reduce high inlet pressure to a lower outlet pressure that is below the maximum allowable operating pressure (H.A.O.P.) for a segment of pipeline. The district regulators may also be used to reduce an intermediate pressure to an even lower utilization pressure. District regulators may be installed for your companys operation to reduce a line segments lost and unaccountable, gas purchased, tapping requirements, or odorization problems, Overpressure protection devices are devices that protect the downstream pipeline in the event of a regulator failure. These devices include the relief valve, the monitor, and the pressure shutoff. These regulators and overpressure protection devices, because of their importance to system operations, must be inspected in accordance to federal and state regulations.
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Document ID: D6022B74

New Ideas In Measurement Real-Time- A Measurement Pcrspective
Author(s): R. C. Chip-Leitschuh, Jr.
Abstract/Introduction:
The environment of the natural gas industry is changing. The state of the industry is in tremendous flux concerning the handling of natural gas business, both physically and contractually. To adapt, it is imperative that we step forward to the challenge ahead of us. That challenge is to be a major contributor to the success of becoming an ideal pipeline operating system. As progressive pipeline companies confront the challenges of todays demanding and competitive environment, trends will continue to develop in the quest for the ideal pipeline operating systems. The ideal pipeline operating system might take on one of several scenarios, however of premium importance is its ability to adapt to change. The most common of these strategies is the concept of Real-Time. This concept however has lead many companies to grapple with the methodologies and issues which arise through implementation and conversion while striving for this innovative, operating philosophy. Those companies which most nearly approach a highly integrated , coordinated and efficient Real-Time system will most certainly command a competitive advantage.
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Document ID: B9A5C003

Electronic Vs. Mechanical Corkecttng Devices
Author(s): Edward L. Deters
Abstract/Introduction:
Correcting devices, used with positive displacement and turbine meters, correct the gas volume measured at meter conditions of pressiire and temperature to the standard volume measured at base conditions of pressure and tenperature. Both mechanical and electronic correctors can accomplish this inportant function with the high degree of accuracy required to produce billable volumes at the sale or purchase point of natural gas. Since the early days of gas neasurement, chart recorders have been used to keep track of the pressure and temperature of the metered volume. They nojnt on the meter and are driven from the index or output wriggler. The charts are processed to determine the correcticn factors necessary to produce standard cubic feet values for billing. Ifechanical correctors were developed in the late 1930s to provide a readout of volume in standard cubic feet at the meter site. This eliminated the need to collect the chart, install a new one and process the chart for billing purposes. A mechanical corrector provides the base volume right on the spot, and can be read just like a residential meter. The corrector mounts directly on the meter using the meters output wriggler to provide the uncorrected volume input as well as provide power to run the correcting mechanisms.
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Document ID: 22EAC4D7

The Indystrys Revised Orifice Metering Standar
Author(s): R E. Beaty,. R. G. Teyssandier,J. E. Gallagher,
Abstract/Introduction:
New research and measurement technologies have produced new equations and mechanical specifications which significantly improve the uncertainty levels for orifice measurement. This paper provides both an introduction and a summary of the four parts of the 1990/91 revision to the orifice standard.
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Document ID: 399A5B8A

Flow Measurement By Insertion Turbine Flow Meters
Author(s): Ron Mccarthy
Abstract/Introduction:
The insertion meter is designed to offer a cost effective means to measure liquids, gas and steam in large pipes or ducts, or in small pipes in which the flow cannot be interrupted. Measurement is achieved by inserting the sensor into the flow line on a stem or shaft. This stem allows correct positioning of the sensor for accurate measurement in the flow line. Typically, insertion meters are installed and retracted from the line through an isolation valve mounted on a riser.
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Document ID: D4D6F713

Odorization
Author(s): G.M. Johnson
Abstract/Introduction:
Odorlzation In the United States is separated into two basic groups, Liquified Petroleum Gas (LPG) Odorlzation and Natural Gas Odori2tion. Ethyl Mercaptan is used as the odorant for LPGs. Natural Gas Odorants are generally a blend of two or more components with the occasional exception of Thiophane. It is important for each odorant user to first determine their odorlzation objective or goal. Odorant blend selection along with compatibility to equipment and gas composition is the next important factor in determining your odorlzation requirements. This paper will give you a basic outline of the major components and blends in use today.
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Document ID: CF4F3EB9

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 the actual measurement process begins. It is the measurement departments job to deliver the results of all of the hard work and money invested.
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Document ID: B92D1BBC

Orifice Meter Testing
Author(s): Gai1 Ledbetter
Abstract/Introduction:
In orifice meter testing there are three primary elements wich must be observed to assure the accuracy of the orifice meter. They are the meter tube, the orifice plate and the orifice meter. Each elanent has criteria wrfiich 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: 33CDE265

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. Over the years one of the objections our customers and bosses have always had, and in many instances continue to have is repeatability and accuracy of our chart integration. Legitimate concerns - if your answer is not repeatable, obviously it isnt accurate. In many cases the manual integration repeatability problem could be improved if productivity was reduced but if you reduce productivity the costs of labor go up, which is a no-no in our business today.
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Document ID: 49320391

Gas Contract Interpretation
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.
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Document ID: 1A0E387C

Electronic Chart Integrators
Author(s): Bryan Billeaud
Abstract/Introduction:
In the natural gas isdustry, measurment and calculation of gas volumes have been accomplished through th use of orifice meter chart records. Machines which make the calculation form these records are a common sight to most companies involved in gas measurement. Electronic equipment, improve especially,have brought about substatial improvement to measurement and calculations due to thier ever increasing speed, accuracy and mathmatical abilities. There are many variables and methods used in the volume calculations generated from these chart records. One important consideration is the pressure extension. The pressure extension is derived directly from a chart record. It is computed from two independent curves on the chart which depict the pressure, in psi, found in an orifice meter tube and the differential pressure, in inches of H2O, of the opposite sides of the orifice. In accordance to the Bernoulli theorum, these two curves dre considered as continuous records over a specified period of time.
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Document ID: BE0F2030

Design Considerations For Orifice Meter Tubes
Author(s): Ray Kendrick
Abstract/Introduction:
What is 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. separating the flanges. Each of these segments should be addressed when designing an orifice measurement installation. The initial assumption must be made that accurate measurement is desired. Many manhours of test work went into the development of the equation and mechanical requirements necessary to achieve the code stated accuracy from use of the equation.
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Document ID: E7F68BFB

Water Vapor Determination Amd 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: 86283AE8

Field Testing Of High Volume Gas Turbine Meters
Author(s): Jim Beeson
Abstract/Introduction:
Arkla Energy Resources developed and currently uses a mobile gas tuibine 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 chronatograph vich is used in actual mass flow coirpitations. This system has several advantages over earlier methods of proving gas turbine meters. Arkla previously proved its larger turiaine 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. It is a fact that a turbine meter proven at 0 PSIG and then put into pressure service will exhibit a K-factor shift in the positive direction. Without sending the meter back to the manufacturer, this shift cannot be accounted for. The sonic nozzle prover calibrates turbine meters under actual operating pressmres, or densities, in lieu of atmospheric pressures, and it calibrates under actual operating temperatures.
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Document ID: 4AE72AA9

Problems In Offshore Gas Measurementproblems And Solutions Encountered In Offshore Measurement
Author(s): Mikel Gaston
Abstract/Introduction:
The next 45 minutes will address some of the major problems and solution encountered with gas measurement on offshore platforms in the Gulf of Mexico. The presentation will also stress the importance of competent measurement personnel and their roles in assuring that accurate measurement occurs. Slides that identify actual equipment installations, safety hazards, weather conditions, and logistics problems will be presented.
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Document ID: 7602294B

The Next 45 Minutes Will Address Some Of The Major Problems And Solution Encountered With Gas Measurement On Offshore Platforms In The Gulf Of Mexico. The Presentation Will Also Stress The Importance Of Competent Measurement Personnel And Their Roles In Assuring That Accurate Measurement Occurs. Slides That Identify Actual Equipment Installations, Safety Hazards, Weather Conditions, And Logistics Problems Will Be Presented.
Author(s): R. C. Chip Leitschuh, Jr.
Abstract/Introduction:
The environment of the natural gas industry is changing. The state of the industry is in tremendous flux concerning the handling of natural gas business, both physically and contractually. To adapt, it is imperative that we step forward to the challenge ahead of us. That challenge is to be a major contributor to the success of becoming an ideal pipeline operating system. As progressive pipeline companies confront the challenges of todays demanding and competitive environment, trends will continue to develop in the quest for the ideal pipeline operating systems. The ideal pipeline operating system might take on one of several scenarios, however of premium importance is its ability to adapt to change. The most common of these strategies is the concept of Real-Time. This concept however has lead many companies to grapple with the methodologies and issues which arise through implementation and conversion while striving for this innovative, operating philosophy. Those companies which most nearly approach a highly integrated , coordinated and efficient Real-Time system will most certainly command a competitive advantage.
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Document ID: 73B9DE7A

Electrohtc Transmtttkrs
Author(s): Jim Griffeth
Abstract/Introduction:
What is a TRANSDUCER? What is a TRANSMITTER? What is the difference between a transducer and a transmitter? What is the difference beftween Gauge, absolute, and differential pressure transducers? Why is one transducer more accurate than another? How does a. transducer & transmitter work? How often should one transducer or transmitter? .calibrate Over the course of this paper we will answer the above questions in enough detail as to satisfy most field technicians.
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Document ID: 4AAA7F91

Regulatory Commission Safety Evaluation Amd Thaining
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, (Ag 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. The first pipeline safety rule occurred in 1937 and required operators to odorize gas after unodorized gas was blamed for the explosion at the Consolidated School in New London that killed 293 children and teachers. Because of Texas size and position as a leading energy producer, it has more pipeline miles and gas systems than any other state. Presently, there are 2091 distribution, 371 transmission (including Jurisdictional gathering lines), 3000 hazardous liquids systems and over 5000 master meter systems. The Railroad Commission of Texas Transportation/Gas Utilities Division is charged with the responsibility of seeing that these systems are operated safely. To accomplish this task, the Pipeline Safety Staff must inspect approximately 220,000 miles of distribution, transmission and liquids lines serving a population of approximately 1A.3 million Texans. The staff consists of 28 field inspectors strategically located in eight regional offices throughout the State. The Railroad Commission utilizes two approaches to pipeline safety: training and inspections (evaluations). These approaches are effectively combined so that operators have contact with our staff members both as instructors and as Inspectors. The goal of our training program is to educate operators about safety regulations and to help them understand how to achieve compliance. The second approach involves inspecting pipeline facilities which is achieved by safety evaluations.
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Document ID: 93E7003F

Design Considerations For Orifice Meter Tubes
Author(s): Kenneth E. Embry
Abstract/Introduction:
The most widely accepted means of measurement of natural gas and other fluids is the Orifice Meter. The primary elements of the orifice meter Include the orifice plate, orifice fitting or flanges, adjacent piping and flow conditioner, or straightening vanes which make up the Meter Tube. The criteria for design, manufacture and application of orifice meters has existed for many years, but with limited support data. Recent studies from the United States and Europe have proven standards for Orifice Meters to be inadequate to achieve the degree of accuracy required. Extensive research conducted recently has identified deficiencies in the previous standards and set forth new standards for design and application criteria for orifice meters. These new standards are established under the API. Chapter 14 - Manual of Petroleum Standards, Section 3 - Concentric, Square-edged Orifice Meters, Part 2 - Specification and Installation Requirements.
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Document ID: C82C0206

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: 69CBB010

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 billing-compatible 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. The Chart Processor computes and prints (for each chart) the chart extension ( iHP), average pressure and flow time. It also stores and prints batch totals on command.
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Document ID: 88D77B5F

Instrumentation And Volume Calculations For Pd And Turbine Meters
Author(s): C. Wayne Burrell
Abstract/Introduction:
Natural gas distribution companies use a variety of instruments to define uncorrected varibles to achieve corrected volumes of gas that passes through PD and Turbine meters. 1. Compensated Indexes 2. Fixed Factors 3. Volume Recorders i 4. Mechanical Volume Correctors 5. Electronic Volume Correctors 6. Data Collection and Communication Generally speaking, LDCs only use compensating indexes on residential and or commercial applications where the loads are too small to justify the cost of more expensive instruments. These meters can be internally temperature compensated types and when used with a good pressure regulator metering gas at elevated pressures a pressure factor can be achieved that would be acceptable accuracy-wise. Some do not use the compensated index because there is normally a built-in error in the index. Thus, you must compensate the compensating index. Rather than do this, most just plug the factor into the billing machine and use the standard index.
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Document ID: 5AF304EF

H,S Detections And Determination
Author(s): James W. Canterbury
Abstract/Introduction:
Hydrogen sulfide (H2S) and total sulfur, in varying amounts, are found in almost all natural gas fields. In some cases, it is so small that the product is referred to as sweet gas. Many fields, however, produce sour gas, which is a gas with an HS and total sulfur level high enough to require its removal or sweetening. Several methods are available to do this sweetening. However, that is a separate subject and not a part of this paper. The following material is designed to increase your knowledge of hydrogen sulfide, total sulphur and the different continuous monitoring equipment used today. Also covered are different installation techniques concerning placement of the equipment, and proper wiring technique for alarm circuits and recorder outputs. The use of a sample preparation system is also covered.
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Document ID: 58B4E394

Low Power Field Flow Computers
Author(s): Don W, Griffies
Abstract/Introduction:
This paper presents an introductory discussion of fieldmounted gas flow computers in general, and the low-power variety in particular. What makes the low-power category different is that these instruments use disposable batteries or very smail, inexpensive solar panels with rechargeable batteries. What makes non-rechargeable batteries practical for this purpose is extremely low power consumption, A pair of ordinary alkaline lantern batteries typically lasts well over a year.
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Document ID: 66C913B3

Instrumentation And Volume Calculations For Pd And Turbine Meters
Author(s): C. Wayne Burrell
Abstract/Introduction:
Natural gas distribution companies use a variety of instruments to define uncorrected varibles to achieve corrected volumes of gas that passes through PD and Turbine meters. 1. Compensated Indexes 2. Fixed Factors 3. Volume Recorders 4. Mechanical Volume Correctors 5. Electronic Volume Correctors 6. Data Collection and Communication Generally speaking, LDCs only use compensating indexes on residential and or conmercial applications where the loads are tbo small to justify the cost of more expensive instruments. These meters can be internally temperature compensated types and when used with a good pressure regulator metering gas at elevated pressures a pressure factor can be achieved that would be acceptable accuracy-wise. Some do not use the compensated index because there is normally a built-in error in the index. Thus, you must compensate the compensating index. Rather than do this, most just plug the factor into the billing machine and use the standard index.
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Document ID: 0B4ED8C9

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. 1 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: D5EE81E8

Applicatioks Of Telemetering
Author(s): Dennis Alters
Abstract/Introduction:
In order to properly understand new applications in telemetering it is mandatory to understand where we have evolved from in the past decade. Early in the 1980s the maj ority of our telemetering consisted of metameters. used in conjuction with some type of multiplexing system. These mechanical units provided years of good service however were somewhat limited in their uses. These units transmitted data through phone lines, microwave and radio frequency to a central monitoring point. The data was converted to strip chart recorders or processed by large main frame computers where it could be monitored by a gas controller. The advantage of the strip chart recorder was you could see flow patterns for several hours at a time but flow volumes had to be calculated by hand and the excessive amounts of processing paper was costly and cumbersome. The main frame system provided several advantages over the strip chart recorders. One main advantage was the main frame could process the raw data from the transmitting unit and display calculated volumes based on pressure, temperature, and differential. These volumes were closer to the actual volumes than any other readings we had been able to transmit before. The main disadvantage was when the main frame system went down a gas control center could not see any status points throughout their system. Due to these problems a second main frame or large backup system was required. Obviously in many cases this made telemetering very expensive.
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Document ID: 973D15EE

Grl Metering Research Facility Update
Author(s): Robert J. Mckee Cecil R. Sparks
Abstract/Introduction:
The Metering Research Facility (MRF) program was initiated at Southwest Research Institute in 1987 by the Gas Research Institute (GRl) in response to gas industry needs for improved accuracy, reliability, and cost effectiveness of metering operations for both custody transfer and other metering applications. The major components of the program have been to: (1) Identify and prioritize industry research needs for improving the state of the art of gas measurement at field metering sites. (2) Design and construct a Low Pressure Loop (LPL) as a world-class test facility for metering applications involving line sizes to 6 inches and pressures to 190 psig, and as a pilot loop for developing and proving design concepts for a larger high pressure facility. (3) Design and construct a High Pressure Loop (HPL) of comparable quality for metering research, development. and testing applications involving meter sizes to 16 inches and pressures to 1440 psig. (4) Conduct research and testing activities in high priority areas as defined by input from gas industry advisors and measurements groups. (5) Make reseirch results available to all segments of the gas industry through a concerted and vigorous program of technology transfer. (6) Make the GRl MRF facilities avaikible for use by other industry groups, gas companies, and equipment manufacturers for research, calibration, and testing programs.
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Document ID: B4528CE7


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