ISO/TC 193 - Natural gas

This document specifies the MNC method for the calculation of the methane number of a gaseous fuel, using the composition of the gas as sole input for the calculation. This document applies to natural gas (and biomethane) and their admixtures with hydrogen.

This document specifies the PKI method for the calculation of the methane number of a gaseous fuel, using the composition of the gas as sole input for the calculation. This document applies to natural gas (and biomethane) and their admixtures with hydrogen.

This document specifies the principles, instruments, materials and experimental conditions for testing Young’s modulus and Poisson’s ratio using triaxial testing method. It also specifies the sampling and mechanical testing procedures, as well as the method and precision requirements for calculating shale mechanical brittleness index based on Young’s modulus and Poisson’s ratio. This document is applicable to reservoir quality evaluation and sweet spot identification in shale gas production.

This document specifies the requirements, sampling, testing, inspection and accompanying documents of slick water. This document is applicable to fracturing fluid systems used in hydraulic fracturing operations in shale gas.

This document describes how to establish the correlation between odorant concentration in air and odour intensity, usually presented in the form of odour intensity curves, following the odour intensity scale presented in Clause 5. This document does not fix a required level of odour intensity in the natural gas: this prescription is specified by local/national regulation.

This document specifies how to design and operate allocation systems for gas production facilities. It describes the most common types, principles and methods used for the allocation of gas and associated liquids. The objective is to provide an approach to current best practice in the oil and gas industry. It applies to gas and liquid allocations to be performed in production, processing, transportation, storage and terminal installations dealing with natural gas and associated liquids as well as end products like sales gas, liquefied petroleum gas (LPG), liquefied natural gas (LNG), condensate and to some extend non-hydrocarbon gases like CO2, H2. This document provides the minimum information needed to develop and implement allocation procedures and systems both for internal purposes (well allocation) and fiscal or commercial applications with different owners and stakeholders. This document can be used to develop gas and liquid processing and transportation agreements and regulatory documents as well as to conduct audit of measurement and allocation systems. It also introduces the areas of competence needed and the terminology used in the industry.

This document gives general guidance for the sampling and gas chromatographic analysis of compressor oil in biomethane or compressed natural gas (CNG). The compressor oil mass fraction is determined by sampling on coalescing filters under defined operational conditions (the two first cubic meters of gas referring to standard conditions, delivered at a refuelling station). Compressor oils are lubricants used in mechanical devices where the purpose is to reduce the volume and increase the pressure of gases for use in a variety of applications. The method is solely applicable to compressed gas (p>18 MPa). The compressor oil content is expressed as mass fraction. The scope of this method is from 3 mg/kg – 30 mg/kg.

This document specifies a method for the determination of the concentration of hydrochloric acid (HCl) and hydrofluoric acid (HF) in biomethane, after absorption on an alkali-impregnated quartz fibre filtre or in a sorbent trap, by ion chromatography (IC) with conductimetric detection. The method is applicable to biomethane for concentration levels for HCl from 0,07 mg/m3 to 35 mg/m3 and for HF from 0,07 mg/m3 to 20 mg/m3. Unless stated otherwise, all concentrations in this document are given under standard reference conditions (see ISO 13443). Other conditions can be applied. This method is also applicable to biogas. This method is intended to support conformity assessment of biomethane and biogas according to specifications, such as the EN 16723 series.

This document describes a method for sampling and analysis of volatile organic compounds (VOCs), including siloxanes, terpenes, organic sulfur compounds, in natural gas and biomethane matrices, using thermal desorption gas chromatography with flame ionization and/or mass spectrometry detectors (TD-GC-FID/MS).

This document describes the test method for the determination of hydrogen sulfide content in natural gas by ultraviolet (UV) absorption method. This document applies to the determination of hydrogen sulfide content in natural gas, in the range from 1 mg/m3 to 50 mg/m3.

This document introduces the production process, the distribution and quality designation of coal-based synthetic natural gas (CBSNG) in many places around the world, and examines whether ISO/TC 193 standards for sampling, test and calculation methods are applicable to the CBSNG product.

This document describes several test methods for measuring the ammonia amount fraction in natural gas and biomethane at the trace level (µmol mol-1). The suitable handling and sampling of pressurised mixtures of ammonia in methane that are applied to several different ammonia measurement systems are described. The measurement systems are comprised of readily available commercial spectroscopic analysers that are specific to ammonia. These NH3 analysers are considered as a black box in terms of their operation, which is dependent on the instructions of the manufacturer. The document describes suitable calibration and measurement strategies to quantify ammonia in (bio)methane around and above the 10 mg m-3 (14 µmol mol-1) level and applies to analysis within absolute pressure ranges of 1 bar – 2 bar, temperatures of 0 °C – 40 °C and relative humidity References are also made to additional standards that are applied either to natural gas analysis or air quality measurements. In this document the matrix gas is always methane or biomethane and the measurand is the amount fraction NH3. NOTE 1 bar = 0,1 MPa =105 Pa; 1 MPa = 1 N/mm2.

This document describes a gas chromatography – ion mobility spectroscopy (GC-IMS) method for the determination of the concentration of siloxanes in biomethane. The method is applicable to the following siloxanes: — hexamethyldisiloxane (L2); — octamethyltrisiloxane (L3); — decamethyltetrasiloxane (L4); — dodecamethylpentasiloxane (L5); — hexamethylcyclotrisiloxane (D3); — octamethylcyclotetrasiloxane (D4); — decamethylcyclopentasiloxane (D5); — dodecamethylcyclohexasiloxane (D6). This document describes suitable calibration and measurement strategies to quantify siloxanes in (bio)methane around and above the 0,3 mg m-3 (14 µmol mol-1) level and applies to analyses within absolute pressure ranges of 1 bar – 2 bar, temperatures of 0 °C – 40 °C and relative humidity

This document specifies a micro gas chromatography method for the on-line or offline determination of the content of five terpenes in biomethane, namely: — alpha-pinene, — beta-pinene, — para-cymene, — limonene, — 3-carene. The method is specifically developed for these five compounds. Information about the compounds is given in Annex A. The method is applicable to the determination of individual amount fractions of the five terpenes from 1 µmol/mol up to and including 10 µmol/mol. With minor modifications it can also be used for terpene amount fractions above 10 µmol/mol.

This document specifies a method for the determination of drag reduction of slick water, which is mainly used to evaluate the drag reduction performance of slick water. This document uses the pipeline method to evaluate the drag reduction, which is currently recognized as the best method to evaluate the drag reduction performance. This document describes the device, experimental conditions and operating steps in detail. The drag reduction value obtained by evaluation according to this document can effectively represent the on-site drag reduction performance.

This document is applicable to the measurement of the total silicon content in gaseous matrices such as biomethane and biogas. Silicon is present in a gas phase contained predominantly in siloxane compounds, trimethylsilane and trimethylsilanol. The analytical form of the silicon measured in liquid phase after conducted sampling and derivatization procedure is soluble hexafluorosilicate anion stable in slightly acidified media. Total silicon is expressed as a mass of silicon in the volume of the analysed gas. This document is applicable to stated gaseous matrices with silicon concentrations up to 5 mg/m3, and it is prevalently intended for the biomethane matrices with Si mass concentration of 0,1 mg/m3 to 0,5 mg/m3. With adaptation to ensure appropriate absorption efficiency, it can be used for higher concentrations. The detection limit of the method is estimated as 0,05 mg/m3 based on a gas sample volume of 0,020 m3. All compounds present in the gas phase are volatile at the absorption and derivatization temperature and gaseous organosilicon species are trapped in absorbance media and derivatized into analytical silicon that is measured by this method. The concentration of the silicon is measured in diluted derivatization media using atomic emission spectrometry upon atomisation/ionisation in microwave or inductively coupled plasma. Unless specified otherwise, all volumes and concentrations refer to standard reference conditions (temperature, 273 K, and pressure, 101,325 kPa). NOTE When using appropriate dilution factors, the method can also be applied for silicon concentrations above 5 mg/m3.

This document gives means for ensuring that samples of natural gas and natural gas substitutes that are conveyed into transmission and distribution grids are representative of the mass to which they are allocated. NOTE To ensure that a particular gas is taken into account in the standard, please see Annex A. This document is applicable for sampling at sites and locations where interchangeability criteria, energy content and network entry conditions are measured and monitored and is particularly relevant at cross border and fiscal measurement stations. It serves as an important source for control applications in natural gas processing and the measurement of trace components. This document is applicable to natural dry gas (single phase - typically gas transiting through natural gas pipelines) sampling only. On occasion a natural gas flow can have entrained liquid hydrocarbons. Attempting to sample a wet natural gas flow introduces the possibility of extra unspecified uncertainties in the resulting flow composition analysis. Sampling a wet gas (two or three phases) flow is outside the scope of this document. This document does not apply to the safety issues associated with gas sampling.

This document gives the specifications and guidelines for the methods to be used in the odorization of natural gas and other methane rich gases delivered through natural gas networks to gas applications under a safety point of view. This document also specifies the principles for the odorization technique (including handling and storage of odorants) and the control of odorization of natural gas and other methane rich gases. NOTE The general requirements for odorants, and the physical and chemical properties of commonly used odorants are specified in ISO 13734.

This document specifies a coulometric procedure for the determination of water content by the Karl Fischer method. The method is applicable to natural gas and other gases which do not react with Karl Fischer (KF) reagents. It applies to water concentrations between 5 mg/m3 and 5 000 mg/m3. Volumes are expressed at temperature of 273,15 K (0 °C) and a pressure of 101,325 kPa (1 atm).

This document specifies general requirements for the determination of water in natural gas using the Karl Fischer method (see Reference [1]). ISO 10101-2 and ISO 10101-3 specify two individual methods of determination, a titration procedure and a coulometric procedure, respectively.

This document specifies a volumetric procedure for the determination of water content in natural gas. Volumes are expressed in cubic metres at a temperature of 273,15 K (0 °C) and a pressure of 101,325 kPa (1 atm). It applies to water concentrations between 5 mg/m3 and 5 000 mg/m3.

This document specifies the determination of the concentration of alkanolamines in biomethane. The measurement method involves thermal desorption gas chromatography with flame ionization and/or mass spectrometry detectors (TD-GC-MS/FID). The described method is specifically developed for the analysis of five amine compounds, namely: — monoethanolamine (MEA); — diglycolamine (DGA); — diethanolamine (DEA); — N-methyldiethanolamine (MDEA); — piperazine (PZ). Information about the compounds is given in Annex A.

This document specifies a text file format - XML file format - for reporting natural gas analysis results and other data relevant to natural gas. The file name is applicable when it includes the extension of .XML (case insensitive). The XML file format is useful for output from ISO 6974-1[1] for composition and ISO 6974-2[2] for uncertainty, for input for ISO 6976[3] and for input for ISO 10723[4] for performance evaluation. Typically these would be the gas composition as provided on an analysis certificate, or results from a performance evaluation that would be read into an Excel spreadsheet for data processing.

This document specifies methods to calculate (dynamic) viscosity, Joule-Thomson coefficient, isentropic exponent, and speed of sound, excluding density, for use in the metering of natural gas flow.

This document surveys the quality designation of CBM all around the world, and analyses whether ISO/TC 193 standards for sampling, test and calculation methods are applicable to CBM.

This document describes a laser Raman spectroscopy method for the quantitative determination of chemical composition of natural gas in upstream area.

This document provides the means for energy determination of natural gas by measurement or by calculation, and describes the related techniques and measures that are necessary to take. The calculation of thermal energy is based on the separate measurement of the quantity, either by mass or by volume, of gas transferred and its measured or calculated calorific value. The general means of calculating uncertainties are also given. Only systems currently in use are described. NOTE Use of such systems in commercial or official trade can require the approval of national authorization agencies, and compliance with legal regulations is required. This document applies to any gas-measuring station from domestic to very large high-pressure transmission. New techniques are not excluded, provided their proven performance is equivalent to, or better than, that of those techniques referred to in this document. Gas-measuring systems are not the subject of this document.

This document specifies a method for the determination of hydrogen sulfide content in working field natural gas of upstream area by laser absorption spectroscopy. The analytical range expressed as mole fraction is 10 × 10−6 to 20 %. The analytical range can be expanded to higher content with specific instrument requirements.

This document describes the precision that can be expected from the gas chromatographic method that is set up in accordance with ISO 6974-1. The stated precision provides values for the magnitude of variability that can be expected between test results when the method described in ISO 6974-1 is applied in one or more competent laboratories. This document also gives guidance on the assessment of bias.

ISO 20729:2017 applies to the determination of total sulfur content in natural gas expressed as sulfur mass concentration ranging from 1 mg/m3 to 200 mg/m3. Natural gas with sulfur contents above 200 mg/m3 can be analysed after dilution with a suitable sulfur-free solvent.

ISO/TR 29922:2017 acts as a repository for those manifold technical details which justify and explain the methods presented in the third edition of ISO 6976 but which are not directly needed in the everyday routine implementation of the standard. Each main clause addresses a specific aspect of the calculational method described in ISO 6976:2016, and is intended to be self-sufficient and essentially independent of each other clause. For this reason, the user should not expect the whole to be accessible to study as a sequentially coherent narrative.

ISO 6976:2016 specifies methods for the calculation of gross calorific value, net calorific value, density, relative density, gross Wobbe index and net Wobbe index of natural gases, natural gas substitutes and other combustible gaseous fuels, when the composition of the gas by mole fraction is known. The methods specified provide the means of calculating the properties of the gas mixture at commonly used reference conditions. Mole fractions by definition sum to unity. Guidance on the achievement of this requirement by chromatographic analysis is available in ISO 6974‑1 and ISO 6974‑2. The methods of calculation require values for various physical properties of the pure components; these values, together with associated uncertainties, are provided in tables and their sources are identified. Methods are given for estimating the standard uncertainties of calculated properties. The methods of calculation of the values of properties on either a molar, mass or volume basis are applicable to any natural gas, natural gas substitute or other combustible fuel that is normally gaseous, except that for properties on the volume basis the method is restricted to mixtures for which the compression factor at reference conditions is greater than 0,9. Example calculations are given in Annex D for the recommended methods of calculation. NOTE 1 The qualifiers "superior", "higher", "upper" and "total" are, for the purposes of this document, synonymous with "gross"; likewise, "inferior" and "lower" are synonymous with "net". The term "heating value" is synonymous with "calorific value"; "mass density" and "specific density" are synonymous with "density"; "specific gravity" is synonymous with "relative density"; "Wobbe number" is synonymous with "Wobbe index"; "compressibility factor" is synonymous with "compression factor". The dimensionless quantity molecular weight is numerically equal to the molar mass in kg·kmol−1. NOTE 2 There are no explicit limits of composition to which the methods described in this document are applicable. However, the restriction of volume-basis calculations to mixtures with a compression factor greater than 0,9 at reference conditions sets implicit limits on composition. NOTE 3 Because the mole fraction of any water present is not normally available from chromatographic analysis, it is common practice to calculate the physical properties on a dry gas basis and to allow for the effects of water vapour in a separate procedure. However, if the mole fraction of water vapour is known then the property calculations can be carried out completely in accordance with the procedures described herein. The effects of water vapour on calorific value, whether the latter is directly measured or calculated, are discussed in ISO/TR 29922. NOTE 4 For aliphatic hydrocarbons of carbon number 7 or above, any isomer present is included with the normal isomer of the same carbon number. NOTE 5 If the user's requirement includes the replacement of, for example, a C6+ or C7+ grouping of analytically unresolved components by a single pseudo-component, then it is the user's own task to set the mole fraction composition, and hence properties, of this pseudo-component so as to be fit for purpose in the particular application. Any so-called "spectator water" and "non-combustible hydrogen sulfide" are treated as pseudo-components by setting the appropriate enthalpy of combustion values to zero.

ISO/TS 14749:2016 concerns the determination of hydrocarbon components up to C7+ in natural gas in upstream petroleum industry, which describes the principle of operation of GC and provides guidelines for selection, evaluation, and factors impacting upon its performance such as sample probe, sample conditioning, installation, operation and troubleshooting.

ISO/TR 12748:2015 describes production flow measurement of wet natural gas streams with WGFMs in surface and subsea facilities. Wet natural gas streams are gas-dominated flows with liquids like water and/or hydrocarbon liquids. ISO/TR 12748:2015 defines terms/symbols, explains the various concepts, and describes best practices of wet gas flow meter design and operation. It addresses metering techniques, testing, installation, commissioning, and operation practices such as maintenance, calibration, and verification. It also provides a theoretical background of this comprehensive, challenging and still evolving measurement technology.

ISO 20765-2:2015 specifies a method to calculate volumetric and caloric properties of natural gases, manufactured fuel gases, and similar mixtures, at conditions where the mixture may be in either the homogeneous (single-phase) gas state, the homogeneous liquid state, or the homogeneous supercritical (dense-fluid) state.

ISO 16960:2014 specifies a method for the determination of total sulfur in the range from 1 mg/m3 to 200 mg/m3 in pipeline natural gas by oxidative microcoulometry. Natural gas with sulfur contents above 200 mg/m3 can be analysed after dilution with a suitable sulfur-free solvent.

ISO 6974-5:2014 describes a gas chromatographic method for the quantitative determination of the content of nitrogen, carbon dioxide and C1 to C5 hydrocarbons individually and a composite C6+ measurement, which represents all hydrocarbons of carbon number 6 and above in natural gas samples.

ISO 14532:2014 establishes the terms, definitions, symbols, and abbreviations used in the field of natural gas. The terms and definitions have been reviewed and studied in order to cover all aspects of any particular term with input from other sources such as European Standards from CEN (The European Committee for Standardization), national standards, and existing definitions in the IGU Dictionary of the Gas Industry. The definitive intention of ISO 14532:2014 is to incorporate the reviewed definitions into the ISO/TC 193 source standards.

ISO 13734;2013 specifies requirements and test methods for organic compounds suitable for odorization of natural gas and natural gas substitutes for public gas supply, hereafter referred to as odorants.

ISO 13686:2013 specifies the parameters required to describe finally processed and, where required, blended natural gas. The main text of ISO 13686:2013 contains a list of these parameters, their units and references to measurement standards. Informative annexes give examples of typical values for these parameters, with the main emphasis on health and safety.

ISO 10723:2012 specifies a method of determining whether an analytical system for natural gas analysis is fit for purpose. It can be used either to determine a range of gas compositions to which the method can be applied, using a specified calibration gas, while satisfying previously defined criteria for the maximum errors and uncertainties on the composition or property or both, or to evaluate the range of errors and uncertainties on the composition or property (calculable from composition) or both when analysing gases within a defined range of composition, using a specified calibration gas.

This part of ISO 6974 describes the process required to determine the uncertainty associated with the mole fraction for each component from a natural gas analysis in accordance with ISO 6974‑1.

ISO/TR 12148:2009 describes the principles of, and general requirements for, the traceable calibration of automatic hydrocarbon-dew-point chilled-mirror instruments using the indirect automatic weighing method (method B) described in ISO 6570:2001 to determine the potential hydrocarbon liquid content of natural gas, or similar gas. The calibration procedure is intended for use by chilled-mirror instruments in downstream applications transferring processed natural gas. If the gas composition is constant, the manual weighing method (method A) described in ISO 6570:2001 is also applicable. The application of this calibration procedure in the upstream area is not excluded a priori, however, currently there is no experience using this procedure in an upstream environment. The usability of data on the potential hydrocarbon liquid content of natural gas for verification, adjustment or calibration of hydrocarbon-dew-point chilled-mirror instruments is based on the condensation behaviour of natural gases. ISO/TR 12148:2009 provides information on the condensation behaviour of natural gases and the various measuring techniques to determine properties, like hydrocarbon dew point and potential hydrocarbon liquid content, related to the condensation behaviour of natural gases.

ISO 15971:2008 concerns the measurement of calorific value of natural gas and natural gas substitutes by non‑separative methods, i.e. methods that do not involve the determination of the gas composition, nor calculations from it. ISO 15971:2008 describes the principles of operation of a variety of instruments in use for this purpose, and provides guidelines for the selection, evaluation, performance assessment, installation and operation of these. Calorific values can be expressed on a mass basis, a molar basis or, more commonly, a volume basis. The working range for superior calorific value of natural gas, on the volume basis, is usually between 30 MJ/m3 and 45 MJ/m3 at standard reference conditions (see ISO 13443). The corresponding range for the Wobbe index is usually between 40 MJ/m3 and 60 MJ/m3. ISO 15971:2008 neither endorses nor disputes the claims of any commercial manufacturer for the performance of an instrument. Its central thesis is that fitness-for-purpose in any particular application (defined in terms of a set of specific operational requirements) can be assessed only by means of a well-designed programme of experimental tests. Guidelines are provided for the proper content of these tests.

ISO/TR 26762:2008 describes the production measurements, in terms of both hardware and procedures, that can be used to allocate the gas and condensate back to the individual concessions, reservoirs and wells in a fair and equitable way. The objective is to give an approach that is recognized to be current best practice and that has a wide support in the oil and gas industry.

ISO 15970:2008 gives requirements and procedures for the measurement of the properties of natural gas that are used mainly for volume calculation and volume conversion: density at reference and at operating conditions, pressure, temperature and compression factor. Only those methods and instruments are considered that are suitable for field operation under the conditions of natural gas transmission and distribution, installed either in-line or on-line, and that do not involve the determination of the gas composition. ISO 15970:2008 gives examples for currently used instruments that are available commercially and of interest to the natural gas industry. The density at reference conditions (sometimes referred to as normal, standard or even base density) is required for conversion of volume data and can be used for other physical properties. Density at operating conditions is measured for mass-flow measurement and volume conversion using the observed line density and can be used for other physical properties. ISO 15970:2008 covers density transducers based on vibrating elements, normally suitable for measuring ranges of 5 kg/m3 to 250 kg/m3. Pressure measurement deals with differential, gauge and absolute pressure transmitters. It considers both analogue and smart transmitters (i.e. microprocessor based instruments) and, if not specified otherwise, the corresponding paragraphs refer to differential, absolute and gauge pressure transmitters without distinction. Temperature measurements in natural gas are performed within the range of conditions under which transmission and distribution are normally carried out (253 K T The compression factor (also known as the compressibility factor or the real gas factor and given the symbol Z) appears, in particular, in equations governing volumetric metering. Moreover, the conversion of volume at metering conditions to volume at defined reference conditions can properly proceed with an accurate knowledge of Z at both relevant pressure and relevant temperature conditions.

ISO/TR 11150:2007 describes the various means of estimating hydrocarbon dew point and hydrocarbon content of natural gas.

ISO 12213 specifies methods for the calculation of compression factors of natural gases, natural gases containing a synthetic admixture and similar mixtures at conditions under which the mixture can exist only as a gas. It is divided into three parts: this part, ISO 12213-3:2006, specifies a method for the calculation of compression factors when the superior calorific value, relative density and carbon dioxide content are known, together with the relevant pressures and temperatures. If hydrogen is present, as is often the case for gases with a synthetic admixture, the hydrogen content also needs to be known. The method is primarily applicable to pipeline quality gases within the ranges of pressure p and temperature T at which transmission and distribution operations normally take place, with an uncertainty of about +/-0,1 %. For wider-ranging applications the uncertainty of the results increases.

ISO 12213 specifies methods for the calculation of compression factors of natural gases, natural gases containing a synthetic admixture and similar mixtures at conditions under which the mixture can exist only as a gas. It is divided into three parts: this part, ISO 12213-1:2006, gives an introduction and provides guidelines for the methods of calculation described in Parts 2 and 3.