ASTM D7708-23a

Standard Test Method for Microscopical Determination of the Reflectance of Vitrinite Dispersed in Sedimentary Rocks

SIGNIFICANCE AND USE
5.1 The mean reflectance of the vitrinite maceral in sedimentary rocks as determined by this test method is used as an indicator of thermal maturity, that is, the progressive geochemical alteration of dispersed organic material experienced during diagenesis, catagenesis, and metagenesis. In the case of hydrocarbon source rocks, three major categories of thermal maturity are defined by vitrinite reflectance: immature (Roran ≤ 0.5 %), mature (Roran ≈ 0.5 % to 1.35 %), and overmature (Roran ≥ 1.35 %) with respect to the generation of liquid hydrocarbons, although not all practitioners agree on these thermal boundaries (10). Thermal maturity as determined by the reflectance of vitrinite dispersed in sedimentary rocks is similar to the rank classification of coals as presented in Classification D388 and measured similarly to the reflectance of vitrinite in coal as presented in Test Method D2798. The mean reflectance of the vitrinite maceral in sedimentary rocks correlates with geochemically determined parameters of thermal maturity and can be used to characterize thermal maturation history, to calibrate burial history models, and to better understand the processes of hydrocarbon generation, migration, and accumulation in conventional and unconventional petroleum systems.
SCOPE
1.1 This test method covers the microscopical determination of the reflectance measured in immersion oil of polished surfaces of vitrinite dispersed in sedimentary rocks. This test method can also be used to determine the reflectance of macerals other than vitrinite dispersed in sedimentary rocks.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 31-Aug-2023
• ICS: 91.100.15 - Mineral materials and products
• Technical Committee: D05 - Coal and Coke
• Drafting Committee: D05.28 - Petrographic Analysis of Coal and Coke

Relations

• Replaces: ASTM D7708-23 - Standard Test Method for Microscopical Determination of the Reflectance of Vitrinite Dispersed in Sedimentary Rocks
• Effective Date: 01-Sep-2023

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D7708 − 23a
Standard Test Method for
Microscopical Determination of the Reflectance of Vitrinite
1
Dispersed in Sedimentary Rocks
This standard is issued under the fixed designation D7708; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope Determine the Precision of a Test Method
1.1 This test method covers the microscopical determination
3. Terminology
of the reflectance measured in immersion oil of polished
surfaces of vitrinite dispersed in sedimentary rocks. This test
3.1 Definitions—For definitions of terms, refer to Terminol-
method can also be used to determine the reflectance of
ogy D121.
macerals other than vitrinite dispersed in sedimentary rocks.
3.2 Abbreviations:
1.2 The values stated in SI units are to be regarded as
3.2.1 R ran—mean random reflectance measured in oil
o
standard. No other units of measurement are included in this
using a fixed microscope stage. Other organizations may use
standard.
other abbreviations for mean random reflectance.
1.3 This standard does not purport to address all of the
3.2.2 R max—mean apparent maximum reflectance mea-
o
safety concerns, if any, associated with its use. It is the
sured in oil using a fixed microscope stage and a rotating
responsibility of the user of this standard to establish appro-
polarizer in the incident light path. Other organizations may
priate safety, health, and environmental practices and deter-
use other abbreviations for mean apparent maximum reflec-
mine the applicability of regulatory limitations prior to use.
tance.
1.4 This international standard was developed in accor-
3.3 Definitions of Terms Specific to This Standard:
dance with internationally recognized principles on standard-
3.3.1 alginite, n—a primary liptinite maceral occurring in
ization established in the Decision on Principles for the
structured morphologies, telalginite, and unstructured
Development of International Standards, Guides and Recom-
morphologies, lamalginite.
mendations issued by the World Trade Organization Technical
3.3.2 bituminite, n—an amorphous primary liptinite maceral
Barriers to Trade (TBT) Committee.
with low reflectance, occasionally characterized by colored
internal reflections in reflected white light and weak orange- to
2. Referenced Documents
2 brown fluorescence, derived from bacterial biomass and the
2.1 ASTM Standards:
bacterial decomposition of algal material and faunal plankton
D121 Terminology of Coal and Coke
(1). Bituminite is equivalent to the amorphous organic matter
D388 Classification of Coals by Rank
3
recognized in strew slides of concentrated kerogen (2).
D2797 Practice for Preparing Coal Samples for Microscopi-
3.3.2.1 Discussion—Bituminite may be distinguished from
cal Analysis by Reflected Light
vitrinite by lower reflectance, as well as higher fluorescence
D2798 Test Method for Microscopical Determination of the
intensity if fluorescence is present in vitrinite. Bituminite has
Vitrinite Reflectance of Coal
poorly-defined wispy boundaries and may be speckled or
E177 Practice for Use of the Terms Precision and Bias in
unevenly colored from dark brown, dark gray, to almost black
ASTM Test Methods
in reflected white light, whereas vitrinite has distinct boundar-
E691 Practice for Conducting an Interlaboratory Study to
ies and is blockier and evenly colored. The occurrence of
bituminite in association with lamalginite and micrinite is
1
common. Bituminite may be expected to occur in lacustrine or
This test method is under the jurisdiction of ASTM Committee D05 on Coal
and Coke and is the direct responsibility of Subcommittee D05.28 on Petrographic
marine settings. It is less commonly present in fluvial or similar
Analysis of Coal and Coke.
proximal depositional environments, where vitrinite may be
Current edition approved Sept. 1, 2023. Published October 2023. Originally
expected to occur in greater abundance.
approved in 2011. Last previous edition approved in 2023 as D7708 – 23. DOI:
10.1520/D7708-23A.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
3
Standards volume information, refer to the standard’s Document Summary page on The boldface numbers in parentheses refer to a list of references at the end of
the ASTM website. this standard.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D7708 − 23 D7708 − 23a
Standard Test Method for
Microscopical Determination of the Reflectance of Vitrinite
1
Dispersed in Sedimentary Rocks
This standard is issued under the fixed designation D7708; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This test method covers the microscopical determination of the reflectance measured in immersion oil of polished surfaces of
vitrinite dispersed in sedimentary rocks. This test method can also be used to determine the reflectance of macerals other than
vitrinite dispersed in sedimentary rocks.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2
2.1 ASTM Standards:
D121 Terminology of Coal and Coke
D388 Classification of Coals by Rank
D2797 Practice for Preparing Coal Samples for Microscopical Analysis by Reflected Light
D2798 Test Method for Microscopical Determination of the Vitrinite Reflectance of Coal
E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
3. Terminology
3.1 Definitions—For definitions of terms, refer to Terminology D121.
3.2 Abbreviations:
3.2.1 R ran—mean random reflectance measured in oil using a fixed microscope stage. Other organizations may use other
o
abbreviations for mean random reflectance.
1
This test method is under the jurisdiction of ASTM Committee D05 on Coal and Coke and is the direct responsibility of Subcommittee D05.28 on Petrographic Analysis
of Coal and Coke.
Current edition approved Jan. 1, 2023Sept. 1, 2023. Published February 2023October 2023. Originally approved in 2011. Last previous edition approved in 20142023 as
D7708 – 14. DOI: 10.1520/D7708-23.23. DOI: 10.1520/D7708-23A.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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D7708 − 23a
3.2.2 R max—mean apparent maximum reflectance measured in oil using a fixed microscope stage and a rotating polarizer in the
o
incident light path. Other organizations may use other abbreviations for mean apparent maximum reflectance.
3.3 Definitions of Terms Specific to This Standard:
3.3.1 alginite, n—a primary liptinite maceral occurring in structured morphologies, telalginite, and unstructured morphologies,
lamalginite.
3.3.2 bituminite, n—an amorphous primary liptinite maceral with low reflectance, occasionally characterized by colored internal
reflections in reflected white light and weak orange- to brown fluorescence, derived from bacterial biomass and the bacterial
decomposition of algal material and faunal plankton (1). Bituminite is equivalent to the amorphous organic matter recognized in
3
strew slides of concentrated kerogen (2).
3.3.2.1 Discussion—
Bituminite may be distinguished from vitrinite by lower reflectance, as well as higher fluorescence intensity if fluorescence is
present in vitrinite. Bituminite has poorly-defined wispy boundaries and may be speckled or unevenly colored from dark brown,
dark gray, to almost black in reflected white light, whereas vitrinite has distinct boundaries and is blockier and evenly colored. The
occurrence of bituminite in association with lamalginite and micrinite is common. Bituminite may be expected to occur in
lacustrine or marine settings. It is less commonl
...