ASTM D7829-23

Standard Guide for Sediment and Water Determination in Crude Oil

SIGNIFICANCE AND USE
4.1 Theoretically, all of the sediment and water determination methods are valid for crude oils containing from 0 % to 100 % by volume sediment and water; the range of application is specified within the scope of each method. The round robins for all methods were conducted on relatively dry oil. All precision and bias statements included in the methods are based upon the round robin data. Analysis becomes more challenging with crude oils containing higher water contents due to the difficulty in obtaining a representative sample, and maintaining the sample quality until analysis begins.  
4.2 Currently, Karl Fischer is generally used for dry crude oils containing less than 5 % water. Distillation is most commonly used for dry and wet crude oils and where separate sediment analysis is available or in situations where the sediment result is not significant. The laboratory centrifuge methods allow for determination of total sediment and water in a single analysis. The field centrifuge method is used when access to controlled laboratory conditions are not available.  
4.3 In the event of a dispute with regard to sediment and water content, contracting parties may refer to the technical specifications table to determine the most appropriate referee method based upon knowledge of and experience with the crude oil or product stream.
SCOPE
1.1 This guide covers a summary of the water and sediment determination methods from the API MPMS Chapter 10 for crude oils. The purpose of this guide is to provide a quick reference to these methodologies such that the reader can make the appropriate decision regarding which method to use based on the associated benefits, uses, drawbacks and limitations.  
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: 30-Sep-2023
• ICS: 75.040 - Crude petroleum
• Technical Committee: D02 - Petroleum Products, Liquid Fuels, and Lubricants
• Drafting Committee: D02.02 - Hydrocarbon Measurement for Custody Transfer (Joint ASTM-API)

Relations

• Replaces: ASTM D7829-13(2018) - Standard Guide for Sediment and Water Determination in Crude Oil
• Effective Date: 01-Oct-2023
• Refers: ASTM D4175-23a - Standard Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants
• Effective Date: 15-Dec-2023
• Refers: ASTM D4175-23e1 - Standard Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants
• Effective Date: 01-Jul-2023
• Refers: ASTM D4175-23 - Standard Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants
• Effective Date: 01-Jul-2023

Overview

ASTM D7829-23 is a standard guide developed by ASTM International for the determination of sediment and water in crude oil. This guide summarizes key methods referenced in API MPMS Chapter 10 and provides a decision framework for selecting the most suitable analysis technique according to crude oil characteristics, precision requirements, and operational constraints. Effective sediment and water determination is crucial for oil quality assessment, refining processes, transport, and custody transfer agreements.

The standard serves as a comprehensive reference, outlining the applicability, benefits, limitations, and practical considerations for each method, helping users optimize accuracy, efficiency, and compliance in crude oil analysis.

Key Topics

• Method Selection: Explains when to use different analytical techniques (distillation, centrifuge, Karl Fischer titration, extraction, membrane filtration) based on oil dryness, sediment and water content, sample handling needs, and laboratory or field conditions.
• Scope and Applicability: Covers crude oils with sediment and water ranging from 0% to 100% by volume, with precision statements tailored to dry oils but methods applicable to broader conditions.
• Sample Handling: Stresses the importance of collecting, mixing, and handling samples to maintain representativity and minimize analytical bias, including suitability for field versus laboratory use.
• Guidance on Dispute Resolution: Advises how contracting parties can choose referee methods for custody transfer or quality assurance disputes, considering method reliability and crude oil characteristics.
• Units of Measurement: Specifies use of SI units as standard, ensuring consistency in global operations.
• Safety and Compliance: Reminds users to establish suitable safety, health, and environmental practices and to verify regulatory requirements prior to method use.

Applications

Sediment and water determination in crude oil has wide-ranging applications, such as:

• Crude Oil Quality Control: Ensures accurate measurement of contaminants affecting downstream processing and refining efficiency.
• Custody Transfer: Provides standardized references for buyer-seller agreements, protecting both parties in commercial transactions and dispute situations.
• Operational Process Optimization: Supports process control in pipelines, storage, and transport by enabling quick assessment of crude suitability and necessary treatment.
• Regulatory Compliance: Helps organizations meet international requirements for crude oil measurement and reporting, supporting inspections, exports, and process certifications.
• Laboratory and Field Analysis: Offers practical guidance for performing analyses in both well-equipped labs and challenging field environments, increasing flexibility across oilfield operations.

Typical users of ASTM D7829-23 include petroleum producers, refiners, pipeline operators, laboratories, inspection companies, and regulatory agencies focused on crude oil measurement, trading, and certification.

Related Standards

ASTM D7829-23 references and complements several key documents essential for sediment and water determination in crude oil, including:

• ASTM D4006 - Water in Crude Oil by Distillation
• ASTM D4007 - Water and Sediment in Crude Oil by Centrifuge Method (Laboratory)
• ASTM D4057 - Manual Sampling of Petroleum and Petroleum Products
• ASTM D4177 - Automatic Sampling of Petroleum and Petroleum Products
• ASTM D473 - Sediment in Crude Oils and Fuel Oils by Extraction Method
• ASTM D4807 - Sediment in Crude Oil by Membrane Filtration
• ASTM D4928 - Water in Crude Oils by Coulometric Karl Fischer Titration
• API MPMS Chapter 10 - Series of methods for sediment and water determination
• ISO and API standards addressing sampling, analysis, and terminology for the petroleum industry

By following ASTM D7829-23, organizations enhance reliability and comparability of sediment and water content results, supporting technical excellence and compliance across the global petroleum value chain.

Keywords: ASTM D7829-23, water determination, sediment determination, crude oil analysis, API MPMS Chapter 10, petroleum standards, oil quality, sampling methods, custody transfer, laboratory testing, field analysis.

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: D7829 − 23
Manual of Petroleum Measurement Standards (MPMS), Technical Report 2573
Standard Guide for
Sediment and Water Determination in Crude Oil
This standard is issued under the fixed designation D7829; 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* D4007 Test Method for Water and Sediment in Crude Oil by
the Centrifuge Method (Laboratory Procedure) (API
1.1 This guide covers a summary of the water and sediment
MPMS Chapter 10.3)
determination methods from the API MPMS Chapter 10 for
D4057 Practice for Manual Sampling of Petroleum and
crude oils. The purpose of this guide is to provide a quick
Petroleum Products (API MPMS Chapter 8.1)
reference to these methodologies such that the reader can make
D4175 Terminology Relating to Petroleum Products, Liquid
the appropriate decision regarding which method to use based
Fuels, and Lubricants
on the associated benefits, uses, drawbacks and limitations.
D4177 Practice for Automatic Sampling of Petroleum and
1.2 The values stated in SI units are to be regarded as
Petroleum Products (API MPMS Chapter 8.2)
standard. No other units of measurement are included in this
D4377 Test Method for Water in Crude Oils by Potentiomet-
standard. 3
ric Karl Fischer Titration (Withdrawn 2020)
1.3 This standard does not purport to address all of the D4807 Test Method for Sediment in Crude Oil by Mem-
safety concerns, if any, associated with its use. It is the
brane Filtration
responsibility of the user of this standard to establish appro- D4928 Test Method for Water in Crude Oils by Coulometric
priate safety, health, and environmental practices and deter-
Karl Fischer Titration
mine the applicability of regulatory limitations prior to use. D5854 Practice for Mixing and Handling of Liquid Samples
1.4 This international standard was developed in accor-
of Petroleum and Petroleum Products (API MPMS Chap-
dance with internationally recognized principles on standard- ter 8.3)
ization established in the Decision on Principles for the
2.2 API Standards:
Development of International Standards, Guides and Recom-
API MPMS Chapter 1 Terms and Definitions Database
mendations issued by the World Trade Organization Technical
API MPMS Chapter 8.1 Standard Practice for Manual Sam-
Barriers to Trade (TBT) Committee.
pling of Petroleum and Petroleum Products (ASTM
D4057)
2. Referenced Documents
API MPMS Chapter 8.2 Standard Practice for Automatic
Sampling of Petroleum and Petroleum Products (ASTM
2.1 ASTM Standards:
D473 Test Method for Sediment in Crude Oils and Fuel Oils D4177)
API MPMS Chapter 8.3 Standard Practice for Mixing and
by the Extraction Method (API MPMS Chapter 10.1)
D4006 Test Method for Water in Crude Oil by Distillation Handling of Liquid Samples of Petroleum and Petroleum
Products (ASTM D5854)
(API MPMSChapter 10.2)
API MPMS Chapter 10.1 Standard Test Method for Sedi-
ment in Crude Oils and Fuel Oils by the Extraction
This guide is under the jurisdiction of ASTM Committee D02 on Petroleum Method (ASTM D473)
Products, Liquid Fuels, and Lubricants and the API Committee on Petroleum
API MPMSChapter 10.2 Standard Test Method for Water in
Measurement, and is the direct responsibility of Subcommittee D02.02 /COMQ the
Crude Oil by Distillation (ASTM D4006)
joint ASTM-API Committee on Hydrocarbon Measurement for Custody Transfer
API MPMSChapter 10.3 Standard Test Method for Water
(Joint ASTM-API). This guide has been approved by the sponsoring committees and
accepted by the Cooperating Societies in accordance with established procedures.
and Sediment in Crude Oil by the Centrifuge Method
This practice was issued as a joint ASTM-API standard in 2013.
(Laboratory Procedure) (ASTM D4007)
Current edition approved Oct. 1, 2023. Published October 2023. Originally
approved in 2013. Last previous edition approved in 2018 as D7829 – 13 (2018).
DOI: 10.1520/D7829-23.
2 3
For referenced ASTM standards, visit the ASTM website, www.astm.org, or The last approved version of this historical standard is referenced on
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM www.astm.org.
Standards volume information, refer to the standard’s Document Summary page on Available from American Petroleum Institute (API), 1220 L. St., NW,
the ASTM website. Washington, DC 20005-4070, http://www.api.org.
*A Summary of Changes section appears at the end of this standard
© Jointly copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, USA and the American Petroleum Institute (API), 1220 L Street NW, Washington DC 20005, USA
D7829 − 23
API MPMS Chapter 10.4 Determination of Water and/or leum and Petroleum Products, API MPMS, and Chapter 8.3
Sediment in Crude Oil by the Centrifuge Method (Field (ASTM D5854) Standard Practice for Mixing and Handling of
Procedure) Liquid Samples of Petroleum and Petroleum Products for
API MPMS Chapter 10.7 Standard Test Method for Water in appropriate sample collection and mixing.
Crude Oils by Potentiometric Karl Fischer Titration
5.3 It is imperative that every sample is mixed sufficiently to
(D4377)
ensure that it is homogeneous. However, with prolonged
API MPMS Chapter 10.8 Standard Test Method for Sedi-
mixing the temperature of the sample will increase. This will
ment in Crude Oil by Membrane Filtration (D4807)
decrease the representative nature of the sample due to
API MPMS Chapter 10.9 Standard Test Method for Water in
evaporative losses. The mixing system must be evaluated to
Crude Oils by Coulometric Karl Fischer Titration (D4928)
determine that the mixing time is sufficient without undue
temperature increases.
3. Terminology
5.4 Sampling error can be a source of bias in analytical
3.1 Definitions:
methods. This is reflected in the precision and bias statement
3.1.1 For terms and definitions used in this guide, refer to
for each method, but it should be considered when evaluating
Terminology D4175 and API MPMS Chapter 1.
methods. A larger sample size will increase the probability that
a sample is representative of the entire parcel and can minimize
4. Significance and Use
the potential bias arising from a less homogenous sample
4.1 Theoretically, all of the sediment and water determina-
stream. Measuring sample size by weight using an analytical
tion methods are valid for crude oils containing from 0 % to
balance is not subject to human error; measuring sample size
100 % by volume sediment and water; the range of application
by volume using analytical glassware is a source of human
is specified within the scope of each method. The round robins
error.
for all methods were conducted on relatively dry oil. All
5.5 When sample size is determined by weight, consider the
precision and bias statements included in the methods are
type of analytical balance used to weigh the sample. Ensure
based upon the round robin data. Analysis becomes more
that the resolution is appropriate, having sufficient significant
challenging with crude oils containing higher water contents
figures, for the analysis.
due to the difficulty in obtaining a representative sample, and
maintaining the sample quality until analysis begins.
6. Report
4.2 Currently, Karl Fischer is generally used for dry crude
Water Only Determination Methods
oils containing less than 5 % water. Distillation is most
commonly used for dry and wet crude oils and where separate
6.1 MPMS Chapter 10.4, Determination of Water and/or
sediment analysis is available or in situations where the
Sediment in Crude Oil by the Centrifuge Method (Field
sediment result is not significant. The laboratory centrifuge
Procedure):
methods allow for determination of total sediment and water in
NOTE 1—ASTM Test Methods D96 for Water and Sediment in Crude
a single analysis. The field centrifuge method is used when
Oil By Centrifuge (Field Procedure), the technically equivalent ASTM
access to controlled laboratory conditions are not available.
standard was withdrawn without replacement in 2000.
4.3 In the event of a dispute with regard to sediment and
6.1.1 Range of Application:
water content, contracting parties may refer to the technical
6.1.1.1 There is no approved precision and bias statement
specifications table to determine the most appropriate referee
for this method.
method based upon knowledge of and experience with the
6.1.1.2 The practical minimum detection limit is 0.025 %
crude oil or product stream.
v/v water. Lower concentrations of water should be reported as
less than 0.025 % v/v or 0 % v/v.
5. Procedure
6.1.1.3 This scope of the method indicates that it applies to
5.1 To obtain the total sediment and water results when the
crude oil, there is no water content specified in the scope.
two are determined by separate methods: First, add the raw,
6.1.2 Interferences, Biases, and Limitations:
unrounded results together, and then round the sum to the
6.1.2.1 The round robin for this method was conducted for
correct significant figure.
combined sediment and water, not the sediment or water
fractions separately. Therefore the precision and bias state-
5.2 It is critically important that the analytical samples are
ments do not apply to analysis of water only.
collected and handled with careful regard to ensure that they
6.1.2.2 This method will typically quantify light alcohols
are representative of the entire parcel. The crude oil or product
such as, (but not limited to), methanol and ethanol in the water
stream should be homogenous at the sampling point, and the
fraction, biasing the water result high.
sample properly mixed prior to analysis. Sub-samples should
6.1.2.3 Centrifuge tubes may be filled directly from a
not be allowed to settle prior to transfer into an analytical
device such as a centrifuge tube, distillation apparatus, or sample tap and analyzed minimizing sample handling. Mini-
mizing sample handling helps to maintain the representative
extraction thimble. Refer to API MPMS Chapter 8.1 (ASTM
D4057) Standard Practice for Manual Sampling of Petroleum nature of a sample.
and Petroleum Products, API MPMS Chapter 8.2 (ASTM 6.1.2.4 A 50 mL sample is used for analysis as measured in
D4177) Standard Practice for Automatic Sampling of Petro- the centrifuge tube.
D7829 − 23
6.1.2.5 The variety of acceptable solvents allows the user to 6.3 MPMS Chapter 10.7 (ASTM D4377-00, IP 356/99),
match the best solvent to the crude type. This can minimize Standard Test Method for Water in Crude Oils by Potentiomet-
bias resulting from precipitated material (asphaltenes or paraf- ric Karl Fischer Titration:
fins) being measured as sediment.
6.3.1 Range of Application:
6.1.2.6 This method will not measure dissolved water, thus 6.3.1.1 The scope of this test method applies to crude oils
the results may be biased low in crudes with dissolved water. containing 0.02 % to 2 % by mass or volume of water.
In addition, depending upon the efficiency of the emulsion
6.3.1.2 The average practical minimum detection limit for
breaker used, some highly stable emulsions may not fully
this method is 0.08 % by mass. This is based upon oil with a
break down which will bias the results low.
relative density of 0.850 and a water equivalence of 4 for the
titration.
6.1.2.7 The sensitivity of this method is limited to the
divisions marked on centrifuge tubes. The intervals range from
6.3.2 Interferences, Biases, and Limitations:
0.025 % to 12.5 % by volume of sediment and water.
6.3.2.1 This test method may be appropriate for crude oils
and products which contain light alcohols such as, but not
6.1.2.8 The method is not highly prescriptive, and lack of
limited to, methanol and ethanol. However, no samples con-
consistency may be a source of variability in the results.
taining alcohols were used in the round robin study; conse-
6.1.2.9 Because the user reads the result directly off the
quently the precision and bias statements in the test method do
glassware, result interpretation is susceptible to human error.
not apply.
6.1.2.10 Because this method is often performed in an
6.3.2.2 Mercaptans in crude oils will bias the results high.
uncontrolled environment, maintaining “stoppered” tubes
This interference is limited with the use of pyridine free
throughout the entire analytical process may help maintain the
reagents. The titration speed and sensitivity settings on Karl
representative nature of the sample.
Fischer units may also mitigate the interference. Refer to the
6.2 MPMS Chapter 10.2 (ASTM D4006, IP 358/82), Stan-
method for information about mercaptan bias.
dard Test Method for Water in Crude Oil by Distillation:
6.3.2.3 This test method allows the user flexibility with
6.2.1 Range of Application:
implementation, the lack of consistency may be a source of
6.2.1.1 The scope of this test method does not indicate a
variability in the results.
range of water content. The round robin, upon which the
6.3.2.4 Syringes of sample may be drawn directly from the
precision and bias statement was developed, ranged from 0.1 %
sample vessel of they may be drawn from a subsample
to 1 % water by volume.
container. The syringe contents are then transferred to the
6.2.1.2 The practical minimum detection limit is 0.025 % by
titration vessel. The use of a subsample container and the
volume. Lower concentrations of sediment and water should be
syringe are a source of error.
reported as less than 0.025 % v/v or 0 % v/v.
6.3.2.5 The analytical sample size is 1 g to 5 g of crude oil.
6.2.2 Interferences, Biases, and Limitations:
6.3.2.6 The resolution for this test method is in the nearest
6.2.2.1 This test method will typically quantify light alco- hundredth 0.08 % by mass for relatively dry crude up to the
hols such as, but not limited to, methanol and ethanol in the nearest 0.4 % by mass for wetter crude oils.
water fraction, biasing the water result high.
6.3.2.7 This repeatability for this test method ranges from
0.012 for 0.05 % by mass of water to 0.040 % by mass for
6.2.2.2 Volumetric glassware may be filled directly from a
sample tap. The volumetric glassware is rinsed with multiple 2.0 % by mass of water.
portions of solvent to ensure full transference of sample into 6.3.2.8 Due to the non-prescriptive flexibility in selection of
the distillation apparatus. This helps ensure that sample did not
solvents and titration parameters, the potentiometric Karl
settle prior to collection of analytical portions. If the sample is Fischer method may have greater interference from mercaptans
allowed to settle, the representative nature may be in question.
than the coulometric method.
6.3.2.9 Samples and aliquots in secondary containers, which
6.2.2.3 Samples used for analysis range from 5 g to 200 g or
includes syringes, may stratify over time and bias the results.
mL, with the smaller sample used for crude oils containing a
higher water content. 6.3.2.10 This test method requires weighing the sample, but
does not include a balance as required equipment.
6.2.2.4 The sensitivity of this test method is limited to the
divisions marked on the distillation trap. The intervals range 6.3.2.11 This test method allows manual titration using
Karl-Fischer reagent. Because the user reads the result directly
from 0.125 % to 0.5 % water by volume. The intervals increase
as the water content of the crude oil increases. off the glassware, result interpretation is susceptible to human
error.
6.2.2.5 The repeatability for this test method ranges from
6.3.2.12 Top loading balances must be calibrated and certi-
0.017 for 0.005 volume % of water to 0.08 for 0.130 volume %
fied regularly.
of water.
6.2.2.6 This test method is more time consuming than the
6.4 MPMS Chapter 10.9 (ASTM D4928-00, IP 386/99),
centrifuge or Karl Fischer methods.
Standard Test Method for Water in Crude Oils by Coulometric
6.2.2.7 This test method requires a laboratory environment Karl Fischer Titration:
to set up and operate.
6.4.1 Range of Application:
6.2.2.8 Because the user reads the result directly off the 6.4.1.1 This procedure is applicable to the determination of
glassware, result interpretation is susceptible to human error. water in crude oils containing from 0.02 % to 5 % water.
D7829 − 23
6.4.1.2 The practical minimum detection limit is 0.005 %. Sediment Only Determination Methods
Lower concentrations of sediment and water should be re-
6.5 MPMS Chapter 10.4, Determination of Water and/or
ported as less than 0.005 % v/v or 0 % v/v.
Sediment in Crude Oil by the Centrifuge Method (Field
6.4.2 Interferences, Biases, and Limitations:
Procedure):
6.4.2.1 This test method may be appropriate for crude oils
NOTE 2—ASTM Test Methods D96 for Water and Sediment in Crude
and products which contain light alcohols such as, but not
Oil By Centrifuge (Field Procedure), the technically equivalent ASTM
standard was withdrawn without replacement in 2000.
limited to, methanol and ethanol. However, no samples con-
taining alcohols were used in the round robin study; conse-
6.5.1 Range of Application:
quently the precision and bias statements in the method do not
6.5.1.1 No round robin has been approved; there is no
apply.
precision and bias statement for this method.
6.5.1.2 The method applies to crude oil, no sediment con-
6.4.2.2 The precision and bias statement was developed
tent range is noted in the scope.
over the range of 0.02 % to 5 %. Due to reagent consumption,
6.5.1.3 The practical minimum detection limit is 0.025 %
it is generally less practical than other methods for very wet
sediment by volume. Lower concentrations of sediment should
crudes.
be reported as less than 0.025 % v/v or 0 % v/v.
...

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: D7829 − 13 (Reapproved 2018) D7829 − 23
Manual of Petroleum Measurement Standards (MPMS), Technical Report 2573
Standard Guide for
Sediment and Water Determination in Crude Oil
This standard is issued under the fixed designation D7829; 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 Scope*
1.1 This guide covers a summary of the water and sediment determination methods from the API MPMS Chapter 10 for crude
oils. The purpose of this guide is to provide a quick reference to these methodologies such that the reader can make the appropriate
decision regarding which method to use based on the associated benefits, uses, drawbacks and limitations.
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
2.1 ASTM Standards:
D473 Test Method for Sediment in Crude Oils and Fuel Oils by the Extraction Method (API MPMS Chapter 10.1)
D4006 Test Method for Water in Crude Oil by Distillation (API MPMSChapter 10.2)
D4007 Test Method for Water and Sediment in Crude Oil by the Centrifuge Method (Laboratory Procedure) (API MPMS
Chapter 10.3)
D4057 Practice for Manual Sampling of Petroleum and Petroleum Products (API MPMS Chapter 8.1)
D4175 Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants
D4177 Practice for Automatic Sampling of Petroleum and Petroleum Products (API MPMS Chapter 8.2)
D4377 Test Method for Water in Crude Oils by Potentiometric Karl Fischer Titration (Withdrawn 2020)
D4807 Test Method for Sediment in Crude Oil by Membrane Filtration
D4928 Test Method for Water in Crude Oils by Coulometric Karl Fischer Titration
D5854 Practice for Mixing and Handling of Liquid Samples of Petroleum and Petroleum Products (API MPMS Chapter 8.3)
This guide is under the jurisdiction of ASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants and the API Committee on Petroleum Measurement,
and is the direct responsibility of Subcommittee D02.02 /COMQ the joint ASTM-API Committee on Hydrocarbon Measurement for Custody Transfer (Joint ASTM-API).
This guide has been approved by the sponsoring committees and accepted by the Cooperating Societies in accordance with established procedures. This practice was issued
as a joint ASTM-API standard in 2013.
Current edition approved Oct. 1, 2018Oct. 1, 2023. Published November 2018October 2023. Originally approved in 2013. Last previous edition approved in 20132018
ɛ1
as D7829 – 13 (2018). . DOI: 10.1520/D7829-13R18.10.1520/D7829-23.
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.
The last approved version of this historical standard is referenced on www.astm.org.
*A Summary of Changes section appears at the end of this standard
© Jointly copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, USA and the American Petroleum Institute (API), 1220 L Street NW, Washington DC 20005, USA
D7829 − 23
2.2 API Standards:
API MPMS Chapter 1 Terms and Definitions Database
API MPMS Chapter 8.1 Standard Practice for Manual Sampling of Petroleum and Petroleum Products (ASTM D4057)
API MPMS Chapter 8.2 Standard Practice for Automatic Sampling of Petroleum and Petroleum Products (ASTM D4177)
API MPMS Chapter 8.3 Standard Practice for Mixing and Handling of Liquid Samples of Petroleum and Petroleum Products
(ASTM D5854)
API MPMS Chapter 10.1 Standard Test Method for Sediment in Crude Oils and Fuel Oils by the Extraction Method (ASTM
D473)
API MPMSChapter 10.2 Standard Test Method for Water in Crude Oil by Distillation (ASTM D4006)
API MPMSChapter 10.3 Standard Test Method for Water and Sediment in Crude Oil by the Centrifuge Method (Laboratory
Procedure) (ASTM D4007)
MPMSAPI MPMS Chapter 10.4 Determination of Water and/or Sediment in Crude Oil by the Centrifuge Method (Field
Procedure)
API MPMS Chapter 10.7 Standard Test Method for Water in Crude Oils by Potentiometric Karl Fischer Titration (D4377)
API MPMS Chapter 10.8 Standard Test Method for Sediment in Crude Oil by Membrane Filtration (D4807)
API MPMS Chapter 10.9 Standard Test Method for Water in Crude Oils by Coulometric Karl Fischer Titration (D4928)
3. Terminology
3.1 Definitions:
3.1.1 For terms and definitions used in this guide, refer to Terminology D4175 and API MPMS Chapter 1.
4. Significance and Use
4.1 Theoretically, all of the sediment and water determination methods are valid for crude oils containing from 0 % to 100 % by
volume sediment and water; the range of application is specified within the scope of each method. The round robins for all methods
were conducted on relatively dry oil. All precision and bias statements included in the methods are based upon the round robin
data. Analysis becomes more challenging with crude oils containing higher water contents due to the difficulty in obtaining a
representative sample, and maintaining the sample quality until analysis begins.
4.2 Currently, Karl Fischer is generally used for dry crude oils containing less than 5 % water. Distillation is most commonly used
for dry and wet crude oils and where separate sediment analysis is available or in situations where the sediment result is not
significant. The laboratory centrifuge methods allow for determination of total sediment and water in a single analysis. The field
centrifuge method is used when access to controlled laboratory conditions are not available.
4.3 In the event of a dispute with regard to sediment and water content, contracting parties may refer to the technical specifications
table to determine the most appropriate referee method based upon knowledge of and experience with the crude oil or product
stream.
5. Procedure
5.1 To obtain the total sediment and water results when the two are determined by separate methods: First, add the raw, unrounded
results together, and then round the sum to the correct significant figure.
5.2 It is critically important that the analytical samples are collected and handled with careful regard to ensure that they are
representative of the entire parcel. The crude oil or product stream should be homogenous at the sampling point, and the sample
properly mixed prior to analysis. Sub-samples should not be allowed to settle prior to transfer into an analytical device such as
a centrifuge tube, distillation apparatus, or extraction thimble. Refer to API MPMS Chapter 8.1 (ASTM D4057) Standard Practice
for Manual Sampling of Petroleum and Petroleum Products, API MPMS Chapter 8.2 (ASTM D4177) Standard Practice for
Automatic Sampling of Petroleum and Petroleum Products, API MPMS, and Chapter 8.3 (ASTM D5854) Standard Practice for
Mixing and Handling of Liquid Samples of Petroleum and Petroleum Products for appropriate sample collection and mixing.
5.3 It is imperative that every sample is mixed sufficiently to ensure that it is homogeneous. However, with prolonged mixing the
Available from American Petroleum Institute (API), 1220 L. St., NW, Washington, DC 20005-4070, http://www.api.org.
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temperature of the sample will increase. This will decrease the representative nature of the sample due to evaporative losses. The
mixing system must be evaluated to determine that the mixing time is sufficient without undue temperature increases.
5.4 Sampling error can be a source of bias in analytical methods. This is reflected in the precision and bias statement for each
method, but it should be considered when evaluating methods. A larger sample size will increase the probability that a sample is
representative of the entire parcel and can minimize the potential bias arising from a less homogenous sample stream. Measuring
sample size by weight using an analytical balance is not subject to human error; measuring sample size by volume using analytical
glassware is a source of human error.
5.5 When sample size is determined by weight, consider the type of analytical balance used to weigh the sample. Ensure that the
resolution is appropriate, having sufficient significant figures, for the analysis.
6. Report
Water Only Determination Methods
6.1 MPMS Chapter 10.4, Determination of Water and/or Sediment in Crude Oil by the Centrifuge Method (Field Procedure):
NOTE 1—ASTM Test Methods D96 for Water and Sediment in Crude Oil By Centrifuge (Field Procedure), the technically equivalent ASTM standard was
withdrawn without replacement in 2000.
6.1.1 Range of Application:
6.1.1.1 There is no approved precision and bias statement for this method.
6.1.1.2 The practical minimum detection limit is 0.025 % v/v water. Lower concentrations of water should be reported as less than
0.025 % v/v or 0 % v/v.
6.1.1.3 This scope of the method indicates that it applies to crude oil, there is no water content specified in the scope.
6.1.2 Interferences, Biases, and Limitations:
6.1.2.1 The round robin for this method was conducted for combined sediment and water, not the sediment or water fractions
separately. Therefore the precision and bias statements do not apply to analysis of water only.
6.1.2.2 This method will typically quantify light alcohols such as, (but not limited to), methanol and ethanol in the water fraction,
biasing the water result high.
6.1.2.3 Centrifuge tubes may be filled directly from a sample tap and analyzed minimizing sample handling. Minimizing sample
handling helps to maintain the representative nature of a sample.
6.1.2.4 A 50 mL sample is used for analysis as measured in the centrifuge tube.
6.1.2.5 The variety of acceptable solvents allows the user to match the best solvent to the crude type. This can minimize bias
resulting from precipitated material (asphaltenes or paraffins) being measured as sediment.
6.1.2.6 This method will not measure dissolved water, thus the results may be biased low in crudes with dissolved water. In
addition, depending upon the efficiency of the emulsion breaker used, some highly stable emulsions may not fully break down
which will bias the results low.
6.1.2.7 The sensitivity of this method is limited to the divisions marked on centrifuge tubes. The intervals range from 0.025 %
to 12.5 % by volume of sediment and water.
6.1.2.8 The method is not highly prescriptive, and lack of consistency may be a source of variability in the results.
6.1.2.9 Because the user reads the result directly off the glassware, result interpretation is susceptible to human error.
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6.1.2.10 Because this method is often performed in an uncontrolled environment, maintaining “stoppered” tubes throughout the
entire analytical process may help maintain the representative nature of the sample.
6.2 MPMS Chapter 10.2 (ASTM D4006, IP 358/82), Standard Test Method for Water in Crude Oil by Distillation:
6.2.1 Range of Application:
6.2.1.1 The scope of this test method does not indicate a range of water content. The round robin, upon which the precision and
bias statement was developed, ranged from 0.1 % to 1 % water by volume.
6.2.1.2 The practical minimum detection limit is 0.025 % by volume. Lower concentrations of sediment and water should be
reported as less than 0.025 % v/v or 0 % v/v.
6.2.2 Interferences, Biases, and Limitations:
6.2.2.1 This test method will typically quantify light alcohols such as, but not limited to, methanol and ethanol in the water
fraction, biasing the water result high.
6.2.2.2 Volumetric glassware may be filled directly from a sample tap. The volumetric glassware is rinsed with multiple portions
of solvent to ensure full transference of sample into the distillation apparatus. This helps ensure that sample did not settle prior
to collection of analytical portions. If the sample is allowed to settle, the representative nature may be in question.
6.2.2.3 Samples used for analysis range from 5 g to 200 g or mL, with the smaller sample used for crude oils containing a higher
water content.
6.2.2.4 The sensitivity of this test method is limited to the divisions marked on the distillation trap. The intervals range from
0.125 % to 0.5 % water by volume. The intervals increase as the water content of the crude oil increases.
6.2.2.5 The repeatability for this test method ranges from 0.017 for 0.005 volume % of water to 0.08 for 0.130 volume % of water.
6.2.2.6 This test method is more time consuming than the centrifuge or Karl Fischer methods.
6.2.2.7 This test method requires a laboratory environment to set up and operate.
6.2.2.8 Because the user reads the result directly off the glassware, result interpretation is susceptible to human error.
6.3 MPMS Chapter 10.7 (ASTM D4377-00, IP 356/99), Standard Test Method for Water in Crude Oils by Potentiometric Karl
Fischer Titration:
6.3.1 Range of Application:
6.3.1.1 The scope of this test method applies to crude oils containing 0.02 to 2 0.02 % to 2 % by mass or volume % of water.
6.3.1.2 The average practical minimum detection limit for this method is 0.08 mass %.0.08 % by mass. This is based upon oil with
a relative density of 0.850 and a water equivalence of 4 for the titration.
6.3.2 Interferences, Biases, and Limitations:
6.3.2.1 This test method may be appropriate for crude oils and products which contain light alcohols such as, but not limited to,
methanol and ethanol. However, no samples containing alcohols were used in the round robin study; consequently the precision
and bias statements in the test method do not apply.
6.3.2.2 Mercaptans in crude oils will bias the results high. This interference is limited with the use of pyridine free reagents. The
titration speed and sensitivity settings on Karl Fischer units may also mitigate the interference. Refer to the method for information
about mercaptan bias.
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6.3.2.3 This test method allows the user flexibility with implementation, the lack of consistency may be a source of variability in
the results.
6.3.2.4 Syringes of sample may be drawn directly from the sample vessel of they may be drawn from a subsample container. The
syringe contents are then transferred to the titration vessel. The use of a subsample container and the syringe are a source of error.
6.3.2.5 The analytical sample size is 1 g to 5 g of crude oil.
6.3.2.6 The resolution for this test method is in the nearest hundredth 0.08 mass % 0.08 % by mass for relatively dry crude up
to the nearest 0.4 mass % 0.4 % by mass for wetter crude oils.
6.3.2.7 This repeatability for this test method ranges from 0.012 for 0.05 mass % 0.05 % by mass of water to 0.040 mass % for
2.0 mass % 0.040 % by mass for 2.0 % by mass of water.
6.3.2.8 Due to the non-prescriptive flexibility in selection of solvents and titration parameters, the potentiometric Karl Fischer
method may have greater interference from mercaptans than the coulometric method.
6.3.2.9 Samples and aliquots in secondary containers, which includes syringes, may stratify over time and bias the results.
6.3.2.10 This test method requires weighing the sample, but does not include a balance as required equipment.
6.3.2.11 This test method allows manual titration using Karl-Fischer reagent. Because the user reads the result directly off the
glassware, result interpretation is susceptible to human error.
6.3.2.12 Top loading balances must be calibrated and certified regularly.
6.4 MPMS Chapter 10.9 (ASTM D4928-00, IP 386/99), Standard Test Method for Water in Crude Oils by Coulometric Karl
Fischer Titration:
6.4.1 Range of Application:
6.4.1.1 This procedure is applicable to the determination of water in crude oils containing from 0.02 % to 5 % 0.02 % to 5 % water.
6.4.1.2 The practical minimum detection limit is 0.005 %. Lower concentrations of sediment and water should be reported as less
than 0.005 % v/v or 0 % v/v.
6.4.2 Interferences, Biases, and Limitations:
6.4.2.1 This test method may be appropriate for crude oils and products which contain light alcohols such as, but not limited to,
methanol and ethanol. However, no samples containing alcohols were used in the round robin study; consequently the precision
and bias statements in the method do not apply.
6.4.2.2 The precision and bias statement was developed over the range of 0.02 % to 5 %. Due to reagent consumption, it is
generally less practical than other methods for very wet crudes.
6.4.2.3 Syringes of sample may be drawn directly from the sample vessel of they may be drawn from a subsample container. The
syringe contents are then transferred to the titration vessel. The use of a subsample container and the syringe are a source of error.
6.4.2.4 The sample size for this test method is 0.25 g to 1.0 g or 0.25 mL to 1.0 mL.
6.4.2.5 Resolution is 0.01 mass % or 0.01 volume %.0.01 % by mass or 0.01 % by volume.
6.4.2.6 The repeatability ranges from 0.003 for 0.01 volume % 0.01 % by volume of water to 0.16 for 5.0 volume % 5.0 % by
volume of water.
6.4.2.7 Mercaptans in crude oils will bias the results high, however this interference is limited when pyridine free reagents are
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used. The titration speed and sensitivity settings on coulometric Karl Fischer units may also mitigate the interference. Refer to the
method for information about mercaptan bias.
6.4.2.8 Samples and aliquots in secondary containers, which include syringes, may stratify over time and bias the results.
6.4.2.9 Karl-Fischer coulometric titration may be conducted by weight or by volume. Analytical balances allow for resolution to
one ten thousandth of a gram and are an objective measurement of sample size. (Balances with lower resolution may be used as
well.) Volumetric measurement is susceptible to human error as the volume is read directly off of the glassware. The volume
resolution of syringes allows for measurement to the nearest hundredth of a millilitre. Syringes with lower resolution may be used
for sample measurement.
6.4.2.10 Using an uncalibrated syringe, or a syringe without verified volumetric markings may be a source of error. In addition,
volume measurement is subjective, which is a potential source of error.
6.4.2.11 It is more difficult to draw higher viscosity crude oils into sample syringes. Volumetric determination of sample size may
not be suitable for some highly viscous crudes.
6.4.2.12 Air bubbles in the syringe may be difficult to detect and will bias results low for volumetrically measured samples.
6.4.2.13 Top loading balances used to determine sample weights, must be calibrated and certified regularly.
6.4.2.14 Because the result is a digital readout, result interpretation or water content is objective.
Sediment Only Determination Methods
6.5 MPMS Chapter 10.4, Determination of Water and/or Sediment in Crude Oil by the Centrifuge Method (Field Procedure):
NOTE 2—ASTM Test Methods D96 for Water and Sediment in Crude Oil By Centrifuge (Field Procedure), the technically equivalent ASTM standard was
withdrawn without replacement in 2000.
6.5.1 Range of Application:
6.5.1.1 No round robin has been approved; there is no precision and bias statement for this method.
6.5.1.2 The method applies to crude oil, no sediment content range is noted in the scope.
6.5.1.3 The practical minimum detection limit is 0.025 % sediment by volume. Lower concentrations of sediment should be
reported as less than 0.025 % v/v or 0 % v/v.
6.5.2 Interferences, Biases, and Limitations:
6.5.2.1 The round robin for this method was conducted for combined sediment and water, not the sediment or water fractions
separately. Therefore the precision and bias statements do not apply to sediment only analysis.
6.5.2.2 The variety of acceptable solvents allows the user to match the best solvent to the crude type. This can minimize bias
resulting from precipitated material being measured as sediment.
6.5.2.3 The method is not highly prescriptive; therefore the results may be less reproducible and repeatable than other Chapter 10
methods. There is no precision and bias data for this method.
6.5.2.4 The sensitivity of this method is limited to the divisions marked on centrifuge tubes. The
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