ISO 24832-1

• Abstract:

  Standardization of the general requirements and calculation methods for the preparation of shale samples based on scanning electron microscopy, scanning image requirements, image processing and analysis techniques. This standard is suitable for digital core scanning and analysis of shale using scanning electron microscopy.

• Status: Not Published
• ICS: 75.020 - Extraction and processing of petroleum and natural gas
• Technical Committee: ISO/TC 193/SC 3 - Upstream area
• Drafting Committee: ISO/TC 193/SC 3 - Upstream area
• Current Stage: 6000 - International Standard under publication
• Start Date: 06-Aug-2026
• Completion Date: 29-Aug-2026

Overview

ISO 24832-1:2026 is an international standard developed by ISO for the upstream natural gas sector, focusing on the determination of pore structure and mineral content in shale. This standard outlines the general requirements and calculation methods for shale sample preparation, imaging, image analysis, and digital core analysis using scanning electron microscopy (SEM) with energy dispersive spectrometer (EDS). It provides a comprehensive protocol to support consistent, accurate, and reliable digital analysis of shale cores crucial for exploration and production activities in shale gas reservoirs.

Key Topics

• Sample Preparation: Procedures for collecting, cutting, mounting, grinding, polishing, and coating shale samples are defined to ensure repeatable and representative analysis results.
• Scanning Electron Microscopy (SEM): Requirements for SEM equipment and imaging protocols, such as accelerating voltage, resolution, and magnification, are specified to capture high-quality images suitable for pore and mineral analysis.
• Energy Dispersive Spectrometer (EDS): Guidelines for the use of EDS in identifying and quantifying mineral composition within the shale samples.
• Image Processing and Analysis: Standardized steps for segmenting images, extracting data on organic and inorganic matter, pores, and calculating surface porosity and pore size distribution.
• Quality Control: Emphasis on repeatability and reproducibility of measurements, referencing ISO 5725 for ensuring accuracy and precision.
• Reporting Requirements: Formats and information to be included in test reports for documentation and data comparability.

Applications

ISO 24832-1:2026 is essential for organizations involved in shale gas exploration and development, including laboratories, research centers, and production companies. Key applications include:

• Reservoir Characterization: Direct observation and quantitative assessment of pore structure and mineral content in shale helps determine reservoir quality, storage capacity, and gas mobility.
• Digital Core Analysis: Provides a foundation for high-resolution 2D and 3D digital models used in formation evaluation.
• Optimizing Drilling and Fracturing: Precise pore and mineral data are critical for designing drilling targets and hydraulic fracturing programs that maximize gas recovery.
• Comparative Analysis and International Collaboration: By standardizing data acquisition and analysis methods, this standard promotes reliable global data sharing between research institutions, service labs, and industry partners.
• Resource Evaluation: Supports the assessment of shale gas potential and aids in decision-making for field development investments.

Related Standards

Organizations applying ISO 24832-1:2026 may also reference these related standards to ensure comprehensive analysis and quality control:

• ISO 5725-2 & ISO 5725-6 - Guidelines for measuring repeatability and reproducibility in measurement methods.
• ISO/IEC 17025 - General requirements for the competence of testing and calibration laboratories.
• ISO 16700 - Scanning electron microscopy-determination of information on morphology and composition.
• Other parts of the ISO 24832 series, which may cover complementary test methods such as FIB-SEM or additional workflows for shale analysis.

Practical Value

Adherence to ISO 24832-1:2026 ensures that pore structure and mineral content analyses in shale are robust, comparable, and reliable. The standard streamlines data quality, enhances efficiency in digital core analysis, and underpins strategic decisions in upstream natural gas projects worldwide. Its application ultimately supports effective resource development, operational optimization, and research collaboration in the evolving shale gas sector.

Keywords: ISO 24832-1, scanning electron microscopy, digital core analysis, shale gas, pore structure, mineral content, energy dispersive spectrometer, natural gas upstream, reservoir evaluation, laboratory standards.

International
Standard
First edition
Natural gas upstream area —
Determination of pore structure
and mineral content for shale —
Part 1:
Scanning electron microscopy with
energy dispersive spectrometer
PROOF/ÉPREUVE
Reference number
© ISO 2026
All rights reserved. Unless otherwise specified, or required in the context of its implementation, 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.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
PROOF/ÉPREUVE
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Apparatus . 3
6 Materials . 4
7 Sample preparation . 4
8 Test procedure . 5
8.1 Determination of pore structure .5
8.1.1 Scanning image .5
8.1.2 Pore structure analysis .5
8.2 Determination of mineral content .7
8.2.1 Backscattered electron imaging .7
8.2.2 Quantitative analysis of minerals .7
9 Quality control . 8
9.1 Repeatability .8
9.1.1 Surface porosity .8
9.1.2 Mineral content .8
9.2 Reproducibility .9
9.2.1 Surface porosity .9
9.2.2 Mineral content .9
10 Test report . 9
Annex A (informative) Example of test report . 10
Bibliography .13
PROOF/ÉPREUVE
iii
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 document 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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 193, Natural gas, Subcommittee SC 3, Upstream
area.
A list of all parts in the ISO 24832 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
PROOF/ÉPREUVE
iv
Introduction
Shale gas, as an unconventional oil and gas resource, is an important component of the world's energy
transformation process. According to the 2015 statistical data from the International Energy Information
Agency, the global technically recoverable shale gas reserves have reached 214 trillion cubic meters.
Compared with other conventional oil and gas resources, shale gas is stored in the shale developed with
micron-sized mineral grains and nanoscale pores, presenting an overall tight structure. This poses
significant challenges for measuring fundamental mineral content and characterizing the pore structure
of shale reservoirs. In shale gas production practices worldwide, considering measurement resolution,
operation generality and result reliability, two methods are widely used:
— scanning electron microscopy (SEM) with energy dispersive spectrometer (EDS);
— focused ion beam – scanning electron microscopy (FIB-SEM) with EDS.
These two methods allow for direct observation and quantification of the mineral composition of shale at
the two-dimensional scale, and nano scale pore structure in both two and three dimensions.
This document aims to improve the accuracy and consistency of analyses, standardize shale evaluation
practices and promote global data comparability to facilitate international cooperation among researchers,
laboratories, exploration and production companies (E&P companies) and other stakeholders in the natural
gas industry.
This document facilitates precise, multi-tier quantitative assessment of shale pores, crucial for reservoir
and resource evaluation, as well as optimizing drilling targets and fracturing designs. Such precision is
paramount for effective exploration and development of shale gas resources.
PROOF/ÉPREUVE
v
International Standard ISO 24832-1:2026(en)
Natural gas upstream area — Determination of pore structure
and mineral content for shale —
Part 1:
Scanning electron microscopy with energy dispersive
spectrometer
IMPORTANT — The electronic file of this document contains colours which are considered to be
useful for the correct understanding of the document. Users should therefore consider printing this
document using a colour printer.
1 Scope
This document describes the principles, equipment, materials, testing procedures, quality control and test
reports for determining shale pore structure and mineral content using scanning electron microscopy
(SEM) with energy dispersive spectrometer (EDS).
This document is applicable to the analysis of pore structure by field emission SEM and mineral content of
shale samples by SEM with EDS in shale gas exploration and development.
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 5725-2, Accuracy (trueness and precision) of measurement methods and results — Part 2: Basic method for
the determination of repeatability and reproducibility of a standard measurement method
ISO 5725-6, Accuracy (trueness and precision) of measurement methods and results — Part 6: Use in practice of
accuracy values
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology 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
image
two-dimensional representation of the specimen surface generated by scanning electron microscopy
[SOURCE: ISO 16700:2016, 3.2, modified — Note 1 to entry has been deleted.]
3.2
charging effect
due to the lack of sufficient conductive pathways, the phenomenon of charge accumulation occurs on the
surface of the sample when it is bombarded by an incident electron beam
PROOF/ÉPREUVE
3.3
working distance
distance between the specimen surface and the bottom plane of the objective lens of the scanning electron
microscopy
[SOURCE: ISO 16700:2016, 3.10]
3.4
organic matter
matter consisting of organic materials derived from organisms (including, but not limited to plants, animals,
algae and microorganisms) and the conversion products of those materials, appearing as black porous/non-
porous medium under scanning electron microscopy observation
[SOURCE: ISO 14055-1:2017, 3.2.8, modified — "plant and/or animal" has been replaced by "organic materials
derived from organisms (including, but not limited to plants, animals, algae and microorganisms)". The
second half of the definition (from "appearing as.") has been added.]
3.5
organic pores
pores developed within the organic matter of shale
3.6
inorganic pores
pores developed within or between inorganic minerals in shale
3.7
surface porosity
ratio of the pore area of the scanned sample to the overall area of the scanned sample
Note 1 to entry: Surface porosity is expressed as a percentage.
3.8
T
SEM
ratio of the total area of organic matter to the entire visual area under scanning electron microscopy
observation
3.9
pore size distribution
incremental surface porosity of each classified range shale pore size obtained by scanning electron
microscopy
3.10
sample
shale selected from drilling cores, drilling cuttings or field outcrop for pore structure and mineral content
determination by scanning electron microscopy with energy dispersive spectrometer
3.11
resolution
minimum distance between two points that can be distinguished by naked eyes in scanning electron
microscopy images
4 Principle
Scan the prepared sample using an SEM to trigger different electron signals to obtain SEM images. Perform
threshold segmentation on different images to identify organic matter, inorganic minerals and pores.
Calculate the T , surface porosity and pore size distribution. Use an energy spectrometer to obtain X-ray
SEM
signal and energy spectra. Compare the energy spectra of different minerals with the mineral standard
database to obtain images of different mineral distributions and mineral composition data. The process for
determining and calculating pore structure and mineral content for shale is shown in Figure 1.
PROOF/ÉPREUVE
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ISO/DISPRF 24832-1:2026(en)
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ISO/TC 193/SC 3
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Secretariat: SAC
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Date: 2026-03-1707-07
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Natural gas upstream area — Determination of pore structure and
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Scanning electron microscopy with energy dispersive spectrometer
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St l D fi iti
ISO/PRF 24832-1:2026(en)
Formatted: Font: Bold
Formatted: HeaderCentered
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All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication
may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying,
Formatted: Adjust space between Latin and Asian text,
or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO
Adjust space between Asian text and numbers
at the address below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: + 41 22 749 01 11
Formatted: French (Switzerland)
EmailE-mail: [e-mail]
Formatted: French (Switzerland)
Website: www.iso.orgwww.iso.org
Formatted: French (Switzerland)
Published in Switzerland
Formatted: Font: 10 pt
Formatted: Font: 10 pt
Formatted: Font: 11 pt
Formatted: FooterPageRomanNumber, Space After: 0
pt, Line spacing: single
ii © ISO #### 2026 – All rights reserved
ii
ISO/DISPRF 24832-1:2026(en) Formatted: Font: 11 pt, Bold, Font color: Auto
Formatted: Font: 11 pt, Bold, Font color: Auto
Formatted: Font: Bold
Contents
Formatted: HeaderCentered, Left
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Foreword . v
Adjust space between Asian text and numbers
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 3
5 Apparatus . 4
6 Materials . 4
7 Sample preparation . 5
8 Test procedure . 5
8.1 Determination of pore structure . 5
8.2 Determination of mineral content . 9
9 Quality control . 10
9.1 Repeatability . 10
9.2 Reproducibility . 10
10 Test report . 10
Annex A (informative) Example of test report . 12
Bibliography . 16

Foreword . iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Apparatus . 3
6 Materials . 4
6.1 Adhesive tape . 4
6.2 Gold, platinum or carbon target . 4
6.3 Nitrogen . 4
6.4 Argon . 4
7 Sample preparation . 4
Formatted: Font: 10 pt
8 Test procedure . 5
8.1 Determination of pore structure . 5 Formatted: Font: 10 pt
8.1.1 Scanning image . 5
Formatted: Font: 10 pt
8.1.2 Pore structure analysis . 5
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8.2 Determination of mineral content . 7
Tab stops: Not at 17.2 cm
8.2.1 Backscattered electron imaging . 7
Formatted: Font: 11 pt
8.2.2 Quantitative analysis of minerals . 7
Formatted: FooterPageRomanNumber, Left, Space
9 Quality control . 8
After: 0 pt, Tab stops: Not at 17.2 cm
© ISO 2026 – All rights reserved
iii
ISO/PRF 24832-1:2026(en)
Formatted: Font: Bold
Formatted: HeaderCentered
9.1 Repeatability . 8
9.1.1 Surface porosity . 8
9.1.2 Mineral content . 8
9.2 Reproducibility . 8
9.2.1 Surface porosity . 8
9.2.2 Mineral content . 8
10 Test report . 8
Annex A (informative) Example of test report . 10
A.1 Results of pore structure evaluation . 10
A.2 Results of mineral content evaluation . 11
Bibliography . 13

Formatted: Font: 10 pt
Formatted: Font: 10 pt
Formatted: Font: 11 pt
Formatted: FooterPageRomanNumber, Space After: 0
pt, Line spacing: single
iv © ISO #### 2026 – All rights reserved
iv
ISO/DISPRF 24832-1:2026(en) Formatted: Font: 11 pt, Bold, Font color: Auto
Formatted: Font: 11 pt, Bold, Font color: Auto
Formatted: Font: Bold
Foreword
Formatted: HeaderCentered, Left
ISO (the International Organization for Standardization) is a worldwide federation of national standards Formatted: Adjust space between Latin and Asian text,
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through Adjust space between Asian text and numbers
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 document 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).
Formatted: English (United Kingdom)
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent rights
in respect thereof. As of the date of publication of this document, ISO had not received notice of (a) patent(s)
which may be required to implement this document. However, implementers are cautioned that this may not
represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
Formatted: English (United Kingdom)
This document was prepared by Technical Committee ISO/TC 193, Natural gas, Subcommittee SC 3, Upstream
Formatted: Adjust space between Latin and Asian text,
area.
Adjust space between Asian text and numbers
A list of all parts in the ISO 24832 series can be found on the ISO website.
Formatted: Default Paragraph Font
Formatted: Default Paragraph Font
Any feedback or questions on this document should be directed to the user’s national standards body. A
Formatted: Default Paragraph Font
complete listing of these bodies can be found at www.iso.org/members.html.
Formatted: Font: 10 pt
Formatted: Font: 10 pt
Formatted: Font: 10 pt
Formatted: FooterCentered, Left, Space Before: 0 pt,
Tab stops: Not at 17.2 cm
Formatted: Font: 11 pt
Formatted: FooterPageRomanNumber, Left, Space
After: 0 pt, Tab stops: Not at 17.2 cm
© ISO 2026 – All rights reserved
v
ISO/PRF 24832-1:2026(en)
Formatted: Font: Bold
Formatted: HeaderCentered
Introduction
Shale gas, as an unconventional oil and gas resource, is an important component of the world's energy
transformation process. According to the 2015 statistical data from the International Energy Information
Agency, the global technically recoverable shale gas reserves have reached 214 trillion cubic meters.
Compared with other conventional oil and gas resources, shale gas is stored in the shale developed with
micron-sized mineral grains and nanoscale pores, presenting an overall tight structure. This poses significant
challenges infor measuring fundamental mineral content and characterizing the pore structure of shale
reservoirs. In shale gas production practices worldwide, considering the measurement resolution, operation
generality and result reliability, two methods are widely used:
— scanning electron microscopy (SEM) with energy dispersive spectrometer (EDS);
Formatted: List Continue 1, No bullets or numbering,
Adjust space between Latin and Asian text, Adjust space
— focused ion beam – scanning electron microscopy (FIB-SEM) with EDS.
between Asian text and numbers
These two methods allow for direct observation and quantification of the mineral composition of shale at the
Formatted: Adjust space between Latin and Asian text,
two-dimensional scale, and nano scale pore structure in both two and three dimensions.
Adjust space between Asian text and numbers
This document aims to improve the accuracy and consistency of analyses, standardize shale evaluation
practices and promote global data comparability to facilitate international cooperation among researchers,
laboratories, exploration and production companies (E&P companies) and other stakeholders in the natural
Formatted: English (United Kingdom)
gas industry.
This document facilitates precise, multi-tier quantitative assessment of shale pores, crucial for reservoir and
resource evaluation, as well as optimizing drilling targets and fracturing designs. Such precision is paramount
for effective exploration and development of shale gas resources.
Formatted: Font: 10 pt
Formatted: Font: 10 pt
Formatted: Font: 11 pt
Formatted: FooterPageRomanNumber, Space After: 0
pt, Line spacing: single
vi © ISO #### 2026 – All rights reserved
vi
DRAFT International Standard ISO/DIS 24832-1:2026(en)

Formatted: Font: Not Bold
Formatted: Header, Left, Space After: 0 pt, Line
spacing: single
Formatted: Main Title 1, Adjust space between Latin
Natural gas upstream area — Determination of pore structure and
and Asian text, Adjust space between Asian text and
mineral content for shale — Part 1: Scanning electron microscopy
numbers
with energy dispersive spectrometer
Part 1:
Scanning electron microscopy with energy dispersive spectrometer
IMPORTANT — The electronic file of this document contains colours which are considered to be useful
for the correct understanding of the document. Users should therefore consider printing this
document using a colour printer.
1 Scope
Formatted: Adjust space between Latin and Asian text,
Adjust space between Asian text and numbers
This document describes the principles, equipment, materials, testing procedures, quality control and test
reports for determining shale pore structure and mineral content using scanning electron microscopy (SEM)
with energy dispersive spectrometer (EDS.).
This document is applicable to the analysis of pore structure by field emission scanning electron
microscopySEM and mineral content of shale samples by SEM with EDS in shale gas exploration and
development.
2 Normative references
Formatted: Default Paragraph Font
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,
Formatted: Default Paragraph Font
the latest edition of the referenced document (including any amendments) applies.
Formatted: Default Paragraph Font
Formatted: Default Paragraph Font
ISO 5725--2, Accuracy (trueness and precision) of measurement methods and results — Part 2: Basic method
for the determination of repeatability and reproducibility of a standard measurement method
Formatted: Adjust space between Latin and Asian text,
Adjust space between Asian text and numbers, Tab
ISO 5725--6, Accuracy (trueness and precision) of measurement methods and results — Part 6: Use in practice
stops: Not at 0.7 cm + 1.4 cm + 2.1 cm + 2.8 cm +
of accuracy values
3.5 cm + 4.2 cm + 4.9 cm + 5.6 cm + 6.3 cm + 7 cm
Formatted: Default Paragraph Font
3 Terms and definitions
Formatted: Default Paragraph Font
For the purposes of this document, the following terms and definitions apply. Formatted: Default Paragraph Font
Formatted: Default Paragraph Font
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
Formatted: Adjust space between Latin and Asian text,
Adjust space between Asian text and numbers
— ISO Online browsing platform: available at https://www.iso.org/obp
Formatted: Adjust space between Latin and Asian text,
— IEC Electropedia: available at https://www.electropedia.org/
Adjust space between Asian text and numbers
Formatted: Default Paragraph Font
3.1
image Formatted: Default Paragraph Font
two-dimensional representation of the specimen surface generated by scanning electron microscopy
Formatted: Default Paragraph Font
Formatted: Footer, Left, Space After: 0 pt, Tab stops:
[SOURCE: ISO 16700:2016, 3.2, modified — Note 1 to entry has been deleted.]
Not at 17.2 cm
ISO/PRF 24832-1:2026(en)
Formatted: Font: Bold
Formatted: HeaderCentered
3.2
charging effect
Formatted: English (United Kingdom)
due to the lack of sufficient conductive pathways, the phenomenon of charge accumulation occurs on the
surface of the sample when it is bombarded by an incident electron beam
3.3
working distance
distance between the specimen surface and the bottom plane of the objective lens of the scanning electron
microscopy
[SOURCE: ISO 16700:2016, 3.10]
Formatted: Default Paragraph Font
Formatted: Default Paragraph Font
3.4
organic matter Formatted: Default Paragraph Font
matter consisting of organic materials derived from organisms (including, but not limited to plants, animals,
Formatted: English (United Kingdom)
algae, and microorganisms),) and the conversion products of those materials, appearing as black porous/non-
Formatted: English (United Kingdom)
porous medium under scanning electron microscopy observation
[SOURCE: ISO 14055-1:2017, 3.2.8, modified — "plant and/or animal" has been replaced by "organic materials
Formatted: Default Paragraph Font
derived from organisms (including, but not limited to plants, animals, algae, and microorganisms)", the)". The
Formatted: Default Paragraph Font
second half of the definition (from "appearing as.") has been added.]
Formatted: Default Paragraph Font
3.5
Formatted: Default Paragraph Font
organic pores
Formatted: Default Paragraph Font
pores developed within the organic matter of shale
Formatted: Default Paragraph Font
3.6
inorganic pores
pores developed within or between inorganic minerals in shale
3.7
surface porosity
ratio of the pore area of the scanned sample to the overall area of the scanned sample
Note 1 to entry: Surface porosity is expressed as a percentage.
Formatted: Adjust space between Latin and Asian text,
Adjust space between Asian text and numbers, Tab
3.8
stops: Not at 0.7 cm + 1.4 cm + 2.1 cm + 2.8 cm +
T
SEM
3.5 cm + 4.2 cm + 4.9 cm + 5.6 cm + 6.3 cm + 7 cm
ratio of the total area of organic matter to the entire visual area under scanning electron microscopy
Formatted: TermNum2, Adjust space between Latin
observation
and Asian text, Adjust space between Asian text and
numbers
3.9
pore size distribution
incremental surface porosity of each classified range shale pore size obtained by scanning electron microscopy
3.10
sample
shale selected from drilling cores, drilling cuttings or field outcrop for pore structure and mineral content
determination by scanning electron microscopy with energy dispersive spectrometer
3.11
Formatted: Font: 10 pt
resolution
Formatted: Font: 10 pt
minimum distance between two points that can be distinguished by naked eyes in scanning electron
Formatted: Font: 11 pt
microscopy images
Formatted: FooterPageNumber, Space After: 0 pt, Line
spacing: single
2 © ISO #### 2026 – All rights reserved
ISO/DISPRF 24832-1:2026(en) Formatted: Font: 11 pt, Bold, Font color: Auto
Formatted: Font: 11 pt, Bold, Font color: Auto
Formatted: Font: Bold
4 Principle
Formatted: HeaderCentered, Left
Scan the prepared sample using an SEM to trigger different electron signals to obtain SEM images. Perform
threshold segmentation on different images to identify organic matter, inorganic minerals and pores. Calculate
the T , surface porosity and pore size distribution. Use an energy spectrometer to obtain X-ray signal and
SEM
energy spectra. Compare the energy spectra of different minerals with the mineral standard database to obtain
images of different mineral distributions and mineral composition data. The process for determining and
calculating pore structure and mineral content for shale is shown in Figure 1.
Shale sampling
Sample preparation
SEM imaging SEM imaging
without EDS with EDS
Morphology
Mineral
image
distribution map
Threshold
segmentation
Organic
Pore Mineral Quartz Feldspar Illite Calcite Other minerals
matter
Inorganic Mineral
Organic
pore content
pore
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Figure 1 — Flowchart of determination of pore structure and mineral content for shale
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© ISO 2026 – All rights reserved
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ISO/PRF 24832-1:2026(en)
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5 Apparatus
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5.1 SEM, the recommendations and requirements of which are as follows:
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a) Accelerating voltage shall be between 1 kV and 20 kV. .
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b) Image resolution: Pixel size shall be less than 10 nm.
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c) Magnification shall range from 500 times to 100 000 times. Formatted
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d) Pore structure analysis should be equipped with a large-area image automatic acquisition system.
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5.2 EDS, the requirements of which shall beare as follows:
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a) Resolution: Mn Kα’s full wave at half maximum shall be less than 135 eV.
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b) Detection element range shall include B- U.
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5.3 Mineral composition, the determination of which should be equipped with an automatic mineral .
analysis system.
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5.4 Argon ion beam, the energy of which shall be between 0,1 KeV and 10 KeV.
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5.5 Coater device, the recommendations and requirements of which are as follows:
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a) It can be plated with carbon, gold or platinum. .
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b) The coating thickness may be controlled.
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5.6 Drying oven or vacuum drying oven, the maximum temperature of which shall exceed 50 °C and
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shall not exceed 100 °C.
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5.7 Mechanical cutting, the maximum cutting depth of which shall exceed 120 mm. Formatted
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5.8 Grinding polishing machine, the media materials of which shall include grinding discs and polishing
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materials.
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5.9 Cold inlay machine, the vacuum degree of which shall be less than 0,1 MPa.
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6 Materials
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6.1 Adhesive tape, aluminium or copper tape, or adhesive carbon tape, shall have a resistivity of no less
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than 5 Ω/mm .
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6.1 Gold, platinum or carbon target
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6.2 Special, special material for SEM is used to spray the target on the surface of non-conductive or poorly .
conductive samples to improve their conductivity, purity > 99,99 %.
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6.2 Nitrogen
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6.3 Purity, purity > 99,99 %.
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6.3 Argon
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6.4 Purity, purity > 99,99 %.
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4 © ISO #### 2026 – All rights reserved
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ISO/DISPRF 24832-1:2026(en) Formatted: Font: 11 pt, Bold, Font color: Auto
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7 Sample preparation
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Shale samples shall be prepared in the following order.:
a) 7.1 Record the basic information of drilling cores, drill cuttings and field outcrops, including the
sampling location or well name, lithology, size, stratigraphi
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