ASTM D3875-15(2023)

Standard Test Method for Alkalinity in Brackish Water, Seawater, and Brines

SIGNIFICANCE AND USE
5.1 Alkalinity as carbonate and bicarbonate of saline water is very important in chemical waterflooding or tertiary recovery processes for recovering petroleum. Alkaline waters offer better wetting to the formation rock and improve oil release. As an additional benefit, ions that provide alkalinity adsorb on rock surfaces occupying adsorption sites and decrease the loss of recovery chemical by adsorption. Determination of alkalinity in waters used in tertiary recovery processes is therefore very important.  
5.2 An alkalinity value is necessary in the calculation of carbonate scaling tendencies of saline waters. It is also necessary to determine the alkalinity if the ionic balance of a water analysis is to be used as a check of the reliability of the analysis.
SCOPE
1.1 This test method covers the determination of alkalinity in brackish water, seawater, and brines.  
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-Mar-2023
• ICS: 13.060.50 - Examination of water for chemical substances
• Technical Committee: D19 - Water
• Drafting Committee: D19.05 - Inorganic Constituents in Water

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: D3875 − 15 (Reapproved 2023)
Standard Test Method for
1
Alkalinity in Brackish Water, Seawater, and Brines
This standard is issued under the fixed designation D3875; 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 4. Summary of Test Method
1.1 This test method covers the determination of alkalinity 4.1 An electrotitrator or pH meter is used to determine the
in brackish water, seawater, and brines. amount of acid necessary to reach pH 8.1 and 4.5, respectively.
The pH values approximate the points where the hydroxide and
1.2 The values stated in SI units are to be regarded as
bicarbonate ions are neutralized.
standard. No other units of measurement are included in this
standard.
5. Significance and Use
1.3 This standard does not purport to address all of the
5.1 Alkalinity as carbonate and bicarbonate of saline water
safety concerns, if any, associated with its use. It is the
is very important in chemical waterflooding or tertiary recov-
responsibility of the user of this standard to establish appro-
ery processes for recovering petroleum. Alkaline waters offer
priate safety, health, and environmental practices and deter-
better wetting to the formation rock and improve oil release. As
mine the applicability of regulatory limitations prior to use.
an additional benefit, ions that provide alkalinity adsorb on
1.4 This international standard was developed in accor-
rock surfaces occupying adsorption sites and decrease the loss
dance with internationally recognized principles on standard-
of recovery chemical by adsorption. Determination of alkalin-
ization established in the Decision on Principles for the
ity in waters used in tertiary recovery processes is therefore
Development of International Standards, Guides and Recom-
very important.
mendations issued by the World Trade Organization Technical
5.2 An alkalinity value is necessary in the calculation of
Barriers to Trade (TBT) Committee.
carbonate scaling tendencies of saline waters. It is also neces-
2. Referenced Documents
sary to determine the alkalinity if the ionic balance of a water
2
analysis is to be used as a check of the reliability of the
2.1 ASTM Standards:
analysis.
D1129 Terminology Relating to Water
D1193 Specification for Reagent Water
6. Interferences
D2777 Practice for Determination of Precision and Bias of
Applicable Test Methods of Committee D19 on Water
6.1 Anions other than bicarbonate, carbonate, or hydroxide
D3370 Practices for Sampling Water from Flowing Process ions that form weakly dissociated acids that participate in
Streams
hydrolysis reactions may also contribute to the alkalinity as
D5847 Practice for Writing Quality Control Specifications may some organic materials. The user of this test method on
for Standard Test Methods for Water Analysis
determining the alkalinity is cautioned that all the effects of the
E200 Practice for Preparation, Standardization, and Storage anions entering into hydrolysis reactions are combined and
of Standard and Reagent Solutions for Chemical Analysis
reported as an equivalent amount of a single substance or two
postulated ions. Included in the reported value is the alkalinity
3. Terminology
resulting from the presence of borate, silicate, sulfide, and
3.1 Definitions—For definitions of terms used in this test phosphate. The effect of borate on the alkalinity value is
method, refer to Terminology D1129.
considered negligible for waters with pH values of 7 or less.
7. Apparatus
1
This test method is under the jurisdiction of ASTM Committee D19 on Water
and is the direct responsibility of Subcommittee D19.05 on Inorganic Constituents
7.1 Electrotitrator or Standard pH Meter with suitable
in Water.
electrodes. Maintenance and standardization of electrodes and
Current edition approved April 1, 2023. Published April 2023. Originally
pH meter should follow manufacturer’s instructions because
approved in 1980. Last previous edition approved in 2015 as D3875 – 15. DOI:
10.1520/D3875-15R23.
performance can be affected by improper treatment.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
NOTE 1—Automatic titrators with combined pH electrode are found
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on useful to increase reliability and save time. The use of an automatic titrator
the ASTM website. is rec
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