ISO/TR 7262:2022

TECHNICAL ISO/TR
REPORT 7262
First edition
2022-01
Natural gas — Coalbed methane
quality designation and the
applicability of ISO/TC 193 current
standards
Gaz naturel — Désignation de la qualité du méthane de houille et
applicabilité des normes en vigueur ISO/TC 193
Reference number
© ISO 2022
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ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols, abbreviations and units . 4
4.1 Symbols and units . 4
4.2 Abbreviations . 4
5 Applicability of sampling standard . 4
6 Applicability of test and calculation standard . 5
6.1 General . 5
6.2 Gas composition . 5
6.2.1 General . 5
6.2.2 Major components . 5
6.2.3 Minor components . 7
6.2.4 Trace constituents . 8
6.3 Gas properties . 10
6.3.1 General . 10
6.3.2 Calorific value, relative density and Wobbe number . 10
6.3.3 Water dew point and water content . 11
6.3.4 Hydrogen dew point and Hydrocarbon liquid content . 11
6.4 Solid particulate matter . 12
Annex A (informative) Technical requirements and test methods for CBM .13
Annex B (informative) The issue of particulate matter in CBM .16
Bibliography .19
iii
Foreword
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iv
Introduction
Coalbed Methane (CBM) is an unconventional form of natural gas and refers to methane-rich gases that
naturally exist in coal seams and surrounding rocks, see also Reference [31]. It is defined as a methane-
rich gas naturally occurring in coal seams (and surrounding rock) typically comprising of 80 % to 95 %
methane with lower proportions of ethane, propane, nitrogen and carbon dioxide (see ISO 18875).
At present, CBM is explored and developed in the United States, Canada, Australia, Russia, India, China
and a few other countries.
Typical CBM contains 80 % to 95 % or more methane and a small portion of ethane, propane, nitrogen
and carbon dioxide, but the composition of coalbed methane varies widely around the world. This
document aims to promote communication and coordination among countries and support the smooth
progress of unconventional natural gas exploration, development, production and custody transfer.
v
TECHNICAL REPORT ISO/TR 7262:2022(E)
Natural gas — Coalbed methane quality designation and
the applicability of ISO/TC 193 current standards
1 Scope
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.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 14532, Natural gas — Vocabulary
ISO 18875, Coalbed methane exploration and development — Terms and definitions
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 14532, ISO 18875 and the
following apply.
NOTE Specific coalbed methane or coal gas mine terms are given in national documents, such as
[30]
GB/T 31537 .
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
normal reference conditions
reference conditions of pressure, temperature, and humidity (state of saturation) equal to 101,325 kPa
and 273,15 K for a gas in the dry state
[SOURCE: ISO 14532:2014, 2.6.1.3]
3.2
ISO standard reference conditions
reference conditions of pressure, temperature, and humidity (state of saturation) equal to 101,325 kPa
and 288,15 K for a real gas in the dry state
[SOURCE: ISO 14532:2014, 2.6.1.4]
3.3
direct sampling
sampling in situations where there is a direct connection between the natural gas to be sampled and
the analytical unit
[SOURCE: ISO 14532:2014, 2.3.1.1]
3.4
indirect sampling
sampling in situations where there is no direct connection between the natural gas to be sampled and
the analytical unit
[SOURCE: ISO 14532:2014, 2.3.1.2]
3.5
representative sample
sample having the same composition as the natural gas sample when the latter is considered as
ahomogeneous whole
[SOURCE: ISO 14532:2014, 2.3.4.2]
3.6
gas chromatographic method
GC method
method of analysis by which the components of a gas mixture are separated using gas chromatography
Note 1 to entry: The sample is passed in a stream of carrier gas through a column that has different retention
properties relative to the components of interest. Different components pass through the column at different
rates and are detected as they elute from the column at different times.
[SOURCE: ISO 14532:2014, 2.2.2.1]
3.7
main component
major component
component whose content influences physical properties
[SOURCE: ISO 14532:2014, 2.5.2.2.1]
3.8
trace component
trace constituent
component present at very low levels
[SOURCE: ISO 14532:2014, 2.5.2.2.3]
3.9
total sulfur
total amount of sulfur found in coal bed methane
[SOURCE: ISO 14532:2014, 2.5.2.3.14]
3.10
compression factor
ratio of the volume of an arbitrary mass of gas at a specified pressure and temperature to the volume of
the same mass of gas under the same conditions as calculated from the ideal-gas law
[SOURCE: ISO 14532:2014, 2.6.2.2]
3.11
density
mass of gas divided by its volume at specified conditions of pressure and temperature
[SOURCE: ISO 14532:2014, 2.6.3.1]
3.12
relative density
ratio of the mass of a gas contained within an arbitrary volume to the mass of dry air of standard
composition that would be contained in the same volume at the same reference conditions
[SOURCE: ISO 14532:2014, 2.6.3.2]
Note 1 to entry: The relative density is also defined in ISO 6976.
3.13
Wobbe index
calorific value on a volumetric basis at specified reference conditions, divided by the square root of the
relative density at the same specified metering reference conditions
[SOURCE: ISO 14532:2014, 2.6.4.3]
3.14
water dew point
temperature at a specified pressure at which water vapour condensation initiates
Note 1 to entry: For any pressure lower than the specified pressure, there is no condensation of water vapours at
this water dew point temperature.
[SOURCE: ISO 14532:2014, 2.6.5.1.1]
3.15
water content
mass concentration of the total amount of water contained in a gas
Note 1 to entry: Water content is expressed in units mass per unit volume.
Note 2 to entry: For gas below the water dew point, this means water in the form of both liquid and vapour; but
for gas above the water dew point, this means only water vapour.
Note 3 to entry: Water content can be also expressed as mole or volume fraction.
[SOURCE: ISO 14532:2014, 2.6.5.1.2]
3.16
hydrocarbon dew point
HCDP
temperature at a specified pressure at which hydrocarbon vapour condensation initiates
Note 1 to entry: In chemical thermodynamics, the “true” hydrocarbon dew point is the temperature (at a stated
pressure) at which the fugacity of the gas and liquid phases is identical. Since measurement of the dew point
involves reduction of the system temperature, this equates to the temperature at which the first appearance of
the liquid phase occurs. At this point, the quantity of liquid phase is infinitesimally small. Since no instrument or
observer is able to detect this infinitesimally small amount, the measured value by a chilled
...