Testing of Heavy Brines

API RECOMMENDED PRACTICE 13J FIFTH EDITION, OCTOBER 2014

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Copyright © 2014 American Petroleum Institute

Foreword

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Contents

Page

1. Scope 3

2. Normative References 3

3. Terms, Definitions, Acronyms, Abbreviations, and Symbols 4

   1. Terms and Definitions 4

   2. Acronyms and Abbreviations 5

   3. Symbols 5

4. Requirements 7

   1. Quality Control Instructions 7

   2. Records Retention 7

5. Calibration of Equipment 7

   1. General Requirements 7

   2. Reagents and Materials for Calibration and Verification 8

   3. General Requirements for Calibration of Particular Apparatus 8

   4. Frequency of Calibration Verification 9

   5. Calibration Verification 9

6. Density 11

   1. General 11

   2. Apparatus 13

   3. Measurement of Specific Gravity or Density Using a Hydrometer 15

   4. Density Corrections for Hydrometers and Brines 16

   5. Calculation of Density in Units Other Than kg/m3 23

   6. Calculation for Pressure and Temperature Compensation 24

7. Crystallization Temperature 28

   1. Principle 28

   2. Apparatus 33

   3. Determination of Crystallization Point 35

   4. Calculation of Crystallization Point 35

8. Brine Clarity 36

   1. Principle 36

   2. Apparatus 36

   3. Determination of Brine Clarity 37

9. Solids Evaluation by Gravimetric Procedure 37

   1. Principle 37

   2. Apparatus 38

   3. Preparation of Glass fiber Filter Disk 38

   4. Selection of Sample Volume 39

   5. Determination of Total Suspended Solids 39

   6. Calculation of Total Suspended Solids 40

   7. Calculation of Precision and Bias 40

   8. Determination of Volatile and Nonvolatile Solids 41

   9. Calculation of Nonvolatile and Volatile Solids 41

10 pH 41

1. Principle 41

2. Reagents and Materials 42

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   Contents

   Page

3. Apparatus 43

4. Measurement of pH 44

5. Precision Statement 45

6. Care of the Electrode 45

1. Iron Contamination 45

   1. Principle 45

   2. Reagents and Materials 46

   3. Apparatus 46

   4. Preparation of Colorimetric Standards 46

   5. Measurement of Iron Contamination 47

   6. Precision Statement 48

2. Daily Completion Fluid Test Report 48

   1. Principle 48

   2. Well identification, Geometry, and Zone Data 49

   3. System Properties 49

   4. Fluids Accounting 50

   5. Cost Accounting 50

   6. Daily Commentary 50

   7. Vendor Representative Identification 51

3. Buffering Capacity of Brines 51

   1. Principle 51

   2. Equipment 52

   3. Reagents and Materials 53

   4. Procedure-Determination of Buffer Concentration 53

   5. Calculation-First Endpoint or Target pH 55

   6. Calculation-Second Endpoint or Target pH 56

Annex A (informative) Completion Fluids Report Form 58

Annex B (informative) Gas Hydrates 59

Annex C (informative) Pressure Crystallization of Brines 61

Annex D (informative) Brine Viscosity 63

Annex E (informative) Principle of Corrosion Testing 64

Bibliography 77

Figures

1. Pressurized Mud Balance 10

2. Atmospheric Mud Balance 10

3. Reading at Bottom of Meniscus 13

4. Calcium Chloride Crystallization Temperature 26

5. Typical Crystallization Curve for Brine 30

6. Typical Crystallization Temperature Measurement Setup 31

7. Example of pH versus Volume of HCl Acid Added 51

8. Example of ∆pH/∆VHCI versus Volume of HCl Acid Added, for More Accurate Determination

of Titration Endpoint 51

A.1 Daily Brine Report 55

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Contents

Tables

Page

1. Temperature Correction Factors for Hydrometers due to Glass Expansion and Contraction 15

2. Estimated Brine Thermal Expansion/Contraction Factors (Conversion Factors) 18

3. Temperature Compensation Factor in SI 22

4. Pressure Compensation Factor in SI 23

5. Temperature Compensation Factors in USC Units 24

6. Pressure Compensation Factors in USC Units 24

7. Calcium Chloride Solutions—Crystallization Temperature 27

8. Sodium Chloride Solutions—Crystallization Temperature 28

E.1 Mechanical Properties of Selected Oil Country Tubular Goods 64

Introduction

API 13J covers the testing of heavy brines commonly used in petroleum and natural gas completion, fracturing, workover, and drill-in fluids. These brines can be purchased or rented from multiple sources and are available worldwide. No single source or limited source of supply is included, either by inference or reference.

Annexes A to E are given for information.

In this standard, quantities are expressed in the International System (SI) of units and are also, where practical, expressed in U.S. Customary (USC) units in parentheses for information.

NOTE The units do not necessarily represent a direct conversion of SI units to USC units, or of USC units to SI units.

This document uses a format for numbers that follows the examples given in API Document Format and Style Manual, First Edition, June 2007 (Editorial Revision, January 2009). This numbering format is different than that used in API 13J, Fourth Edition. In this document, the decimal mark is a period and separates the whole part from the fractional part of a number. No spaces are used in the numbering format. The thousands separator is a comma and is only used for numbers greater than 10,000 (i.e. 5000 items, 12,500 bags).

Consideration has been given to the precision of the instrument making the measurement. For example, thermometers are typically marked in one degree increments, thus temperature values have been rounded to the nearest degree. However, for certain critical measurements such as brine crystallization, thermometers are typically calibrated and used to 0.05 °C (0.1 °F).

Calibrating an instrument refers to assuring the accuracy of the measurement. Accuracy is the degree of conformity of a measurement of a quantity to its actual or true value. Accuracy is related to precision, or reproducibility of a measurement. Precision is the degree to which further measurements or calculations will show the same or similar results. Precision is characterized in terms of the standard deviation of the measurement. The results of calculations or a measurement can be accurate but not precise, precise but not accurate, neither, or both. A result is valid if it is both accurate and precise.

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Testing of Heavy Brines

1. Scope

   
   

   API 13J covers the physical properties, potential contaminants, and test procedures for heavy brine fluids manufactured for use in oil and gas well drilling, completion, fracturing, and workover fluids.

   
   

   API 13J provides methods for assessing the performance and physical characteristics of heavy brines for use in field operations. It includes procedures for evaluating the density or specific gravity, the clarity or amount of particulate matter carried in the brines, the crystallization point or the temperature (both ambient and under pressure) at which the brines make the transition between liquid and solid, the pH, and iron contamination.

   
   

   It also contains a discussion of gas hydrate formation and mitigation, brine viscosity, corrosion testing, buffering capacity, and a standardized reporting form (see Figure A.1).

   
   

   API 13J is intended for the use of manufacturers, service companies, and end users of heavy brines.

   
   

2. Normative References

   
   

   The following referenced documents are indispensable for the application 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.

   
   

   API Recommended Practice 13B-1, Recommended Practice for Field Testing Water-based Drilling Fluids

   
   

   ASTM E77 1, Standard Test Method for Inspection and Verification of Thermometers

   
   

   NBS (NIST) Circular 555 2, Testing of Hydrometers, October 22, 1954 NIST SRM 185h, Potassium Hydrogen Phthalate, pH Standard

   NIST SRM 186g, Potassium Dihydrogen Phosphate, pH Standard

   
   

   NIST SRM 191C, pH Standards

   
   

3. Terms, Definitions, Acronyms, Abbreviations, and Symbols

3.1 Terms and Definitions

For the purposes of this document, the following terms and definitions apply.

3.1.1

ACS reagent grade

Grade of chemical that meets purity standards as specified by the American Chemical Society (ACS).

1. ASTM International, 100 Barr Harbor Drive, West Conshocken, Pennyslvania 19428. www.astm.org.

2. National Institute of Standards and Technology, 100 Bureau Drive, Stop 3460, Gaithersburg, Maryland 20899. www.nist.gov.

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