ISO 18875:2015

Coalbed methane exploration and development - Terms and definitions

ISO 18875:2015 provides terminology on geology and exploration, engineering construction, field development and production in coalbed methane industry. This International Standard does not contain surface gathering.

Exploration et développement du méthane de houille — Termes et définitions

General Information

• Status: Published
• Publication Date: 23-Nov-2015
• ICS: 01.040.73 - Mining and minerals (Vocabularies)
• ICS: 73.020 - Mining and quarrying
• Technical Committee: ISO/TC 263 - Coalbed methane (CBM)
• Drafting Committee: ISO/TC 263 - Coalbed methane (CBM)
• Current Stage: 9093 - International Standard confirmed
• Start Date: 05-Aug-2021
• Completion Date: 13-Dec-2025

Overview

ISO 18875:2015 - Coalbed methane exploration and development - Terms and definitions - is an International Standard that establishes consistent terminology for the coalbed methane (CBM) industry. It covers key vocabulary used in geology and exploration, engineering and construction, and field development and production of CBM wells. The standard standardizes definitions for terms such as coalbed methane (CBM), adsorption/desorption, Langmuir volume and pressure, cleat and fracture, well types (directional, horizontal, multi-lateral), completions, stimulation (including hydraulic fracturing), and production concepts like flowing bottomhole pressure (FBHP). ISO 18875:2015 explicitly does not cover surface gathering systems.

Key topics and requirements

ISO 18875:2015 is a terminology document rather than a procedural or performance standard. Key technical topics included are:

• Geology & exploration: definitions for CBM, gas content, CBM reservoir, coal rank, adsorption isotherm, Langmuir parameters, diffusion coefficient, seismic exploration, resources and reserves.
• Engineering & construction: standardized terms for drilling and well geometry (measured depth, true vertical depth, azimuth, dog-leg severity), casing programme, directional/horizontal and cluster wells, coring, cementing, and well completion methods (open hole, cased hole, cavern, screen pipe).
• Stimulation & fracturing: terms describing hydraulic fracturing, proppant, fracture conductivity, fracture pressure/gradient, staged fracturing and re-fracturing.
• Development & production: well patterns, drainage, inter-well interference, flowing bottomhole pressure (FBHP), casing pressure, coal fines and mitigation (clamp off), and basic production operations.

As a definitions standard, its primary “requirements” are to use the standardized terms and definitions to avoid ambiguity in technical documents, contracts, reports and cross-border projects.

Applications and users

ISO 18875:2015 is useful to:

• CBM operators and field engineers for consistent reporting and design communication.
• Geoscientists and reservoir engineers when describing reservoir properties (adsorption, Langmuir parameters, gas content).
• Drilling, completion and stimulation contractors for unambiguous procedural documents and procurement specs.
• Regulators, consultants and auditors who assess permits, environmental reports and safety documents.
• Standards writers, translators and educators who need harmonized terminology for training materials, international collaboration and documentation.

Using ISO 18875:2015 helps reduce misunderstandings in project specifications, technical papers, and multinational operations involving coalbed methane exploration, engineering and production.

Related standards

Several ISO documents and industry glossaries are cited within ISO 18875:2015 (e.g., ISO 15901‑2, ISO 3529‑1, ISO 9346, ISO 1213‑2, ISO 7404‑1) and the standard was prepared by ISO/TC 263 (Coalbed methane). For procedural or safety requirements, consult additional ISO standards and industry codes relevant to drilling, fracturing and gas handling.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 18875
First edition
2015-12-15
Coalbed methane exploration and
development — Terms and definitions
Exploration et développement du méthane de houille — Termes et
définitions
Reference number
©
ISO 2015
© ISO 2015, Published in Switzerland
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
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ii © ISO 2015 – All rights reserved

Contents Page
Foreword .iv
1 Scope . 1
2 Terms relating to geology and exploration . 1
3 Terms relating to engineering and construction . 5
4 Terms relating to development and production. 8
Bibliography .11
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical
Barriers to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 263, Coalbed methane (CBM).
iv © ISO 2015 – All rights reserved

INTERNATIONAL STANDARD ISO 18875:2015(E)
Coalbed methane exploration and development — Terms
and definitions
1 Scope
This International Standard provides terminology on geology and exploration, engineering construction,
field development and production in coalbed methane industry. This International Standard does not
contain surface gathering.
2 Terms relating to geology and exploration
2.1
coalbed methane
CBM
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
Note 1 to entry: In common international use, this term refers to methane recovered from un-mined coal seams
using surface boreholes.
2.2
adsorption
enrichment of the absorptive gas at the external and accessible internal surfaces of a solid material
(coal matrix)
[SOURCE: ISO 15901-2:2006, 3.2]
2.3
desorption
opposite of adsorption (2.2), in which adsorbed gases leave the surface of a solid material (coal matrix)
Note 1 to entry: The liberation can be spontaneous but can be accelerated by physical actions.
[SOURCE: ISO 3529-1:1981, 1.13.2]
2.4
gas content
volume of gas per unit mass of coal, usually expressed in cubic meter of gas per ton of coal under
standard temperature and pressure (STP) conditions
Note 1 to entry: Unit is m /t or cm³/g. STP conditions are 100 000 Pa and 0 °C (273,15 K).
2.5
CBM content
volume of hydrocarbon gas per unit mass of coal, usually expressed in cubic meter of gas per ton of coal
under standard temperature and pressure (STP) conditions
Note 1 to entry: Unit is m /t or cm³/g. STP conditions are 100 000 Pa and 0 °C (273,15 K).
2.6
CBM reservoir
coal seams and surrounding rock with hydrocarbon resources that can potentially be extracted for
commercial purposes
2.7
initial reservoir pressure
P
i
initial gas pressure measured in a reservoir, prior to the start of production
[SOURCE: WWW.GLOSSARY.OILFIELD.SLB.COM]
2.8
pressure gradient
pressure change with distance ratio of fluid pressure in the middle of the coal seam and reservoir depth
rate of pressure change with respect to depth of coalbed methane reservoir in unit depth, MPa/m,
increasing pressure value of coalbed methane reservoir in unit depth, MPa/m
2.9
abandonment pressure
lowest pressure at which commercial production can be maintained under present economic and
technical conditions expressed by flowing bottom hole pressure (FBHP)
2.10
adsorption isotherm
relationship between the amount of gas adsorbed and the equilibrium pressure of the gas at
constant temperature
Note 1 to entry: Normally described by the Langmuir equation Vads=VL · (p/(PL+p)).
[SOURCE: ISO 15901-2:2006, 3.5]
2.11
Langmuir volume
VL
maximum adsorbed gas content per unit mass of coal at infinite pressure under particular
temperature conditions
2.12
Langmuir pressure
P
L
pressure at which half of the Langmuir volume exists within the coal under particular temperature
conditions
2.13
adsorption time
time in hour or day taken for 63,2% of the total absorbed gas to desorb from the matrix
2.14
adsorption saturation
ratio of measured gas content to the maximum adsorbed gas content in theory per unit mass of coal
under particular CBM reservoir pressure and temperature conditions
2.15
critical desorption pressure
pressure in which the gas begins to desorb from the coal matrix as the CBM reservoir pressure declines
2.16
shrinkage
contraction coefficient
decrease in volume of coal matrix after gas desorption expressed as a percentage of the initial volume
[SOURCE: ISO 14616:1997, 2.2 — modified]
2 © ISO 2015 – All rights reserved

2.17
diffusion coefficient
rate of gas diffusion through a material
Note 1 to entry: Expressed in m /s.
Note 2 to entry: Express flow ability of coalbed methane depending on concentration.
[SOURCE: ISO 9346:2007,3.34]
2.18
dual porosity system
rock characterized by primary porosity from original deposition and secondary porosity from some
other mechanism [cleat (2.20) or fracture (2.19)] and in which all flow to the well effectively occurs in
one porosity system, and most of the fluid is stored in the other
[SOURCE: WWW.GLOSSARY.OILFIELD.SLB.COM — modified]
2.19
fracture
natural fractures in a formation resulting from external stress, usually being associated with a
displacement
2.20
cleat
natural fractures (2.19) in a coal seam usually being associated with coalification (2.21)
Note 1 to entry: Normally in a form as two groups of parallel fractures orthogonal with each other the group with
better fracture continuity is called surface cleat (face cleat), the other group limited by surface cleat is called end
cleat (butt cleat).
2.21
coalification
process by which deposited and compacted plant remains are transformed into coal
Note 1 to entry: Includes diagenesis and metamorphism.
[SOURCE: ISO 1213-2:1992, 3.29]
2.22
coal rank
position of a coal in the coalification series from lignite coal (low rank) to anthracite (high rank),
indicating maturity in terms of chemical and physical properties
[SOURCE: ISO 7404-1:1994, 2.1.3]
2.23
CBM exploration
initial phase in coalbed methane operations that includes generation of a prospect or play or both, and
drilling of an exploration well
[SOURCE: WWW.GLOSSARY.OILFIELD.SLB.COM]
2.24
CBM resources
naturally occurring concentrations or reservoirs of coalbed methane in coal seams and surrounding
rock in such forms and amounts that economic extraction is currently or potentially feasible
[SOURCE: WWW.EIA.GOV/TOOLS/GLOSSARY]
2.25
original CBM in place
volume of coalbed methane in a reservoir prior to production
2.26
recovery factor
ratio of recoverable amount of hydrocarbon initially in place
[SOURCE: WWW.GLOSSARY.OILFIELD.SLB.COM]
2.27
reserve
portion of the demonstrated reserve base that is estimated to be recoverable at the time of determination
Note 1 to entry: Derived by applying a recovery factor to that component of the identified resource designated as
the demonstrated reserve base.
2.28
CBM resource abundance
amount of hydrocarbons in unit area
2.29
zone evaluation
screening of various zones to decide on one or more favorable zone through comprehensive
geological research
2.30
prospecting well
wildcat well
well drilled for the purpose of discovering a new field or reservoir in the new frontier
[SOURCE: http://www.mpgpetroleum.com/glossary.html]
2.31
appraisal well
wells drilled after gas has been discovered, in order to establish the limits of the accumulation in terms
of both the area extent and thickness of the reservoir and the volume of hydrocarbons it contains, and
in order to obtain fluid samples to investigate the distribution of fluid properties in the reservoir
2.32
dirt band
parting
layer of mineral matter lying parallel to the bedding plane in a seam of coal
[SOURCE: ISO 1213-2:1992]
2.33
ash
residue obtained by incineration of a solid mineral fuel under specified conditions
[SOURCE: ISO 1213-2:1992]
2.34
volatile matter
loss in mass, corrected for moisture, when a solid mineral fuel is heated out of contact with air under
specified conditions
[SOURCE: ISO 1213-2:1992]
2.35
proximate analysis
analysis of a solid mineral fuel reported in terms of moisture, volatile matter (2.34), ash (2.33) and fixed
carbon
[SOURCE: ISO 1213-2:1992, 3.134]
4 © ISO 2015 – All rights reserved
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