Table Common Brine Systems

Single-Salt Brines

Approximate Maximum Density, !b/gal

Potassium chloridc (K.Ci) Sodium chloride (NaCl) Calcium chloridc (CaCE) Calcium bromide (CaBr,)

14.2

Two-Salt Brines

Calcium chloride/calcium bromide

15.1

(CaCyCaBrJ

Three-Salt Brines Calcium chloride/calcium bromide/zinc

19.2

bromide (CaCl2/CaBr,/ZhBr2)

The potassium ion is particularly effective at plugging the clay lattice to minimize hydration of formation clays, as shown in Fig. 8-7.

A sodium chloride system (NaCl) is probably the most common brine water used in drilling, completion, and workover operations due to its availability. The maximum density for a sodium chloride brine is 10.0 lb/gal at 60°F. Note that a density of 9.7 lb/gal is relatively easy to achieve. The range from 9.7 to 10.0 lb/gal requires special attention.

Calcium chloride mixtures are used commonly when densities from 9.7 to 11.6 lb/gal are required. The CaCh fluid is used in many workover and completion operations. The freezing (crystallization) point of an 11.6-Ib/gaJ CaCE brine is 44°F, which may cause operating difficulties at low surface temperatures.

Brine systems requiring densities to 15.1 lb/gal use a two-salt mixture of calcium chloride and calcium bromide (CaCl2 and CaBr,). The basic ingredient of this brine is a calcium bromide solution with a density of 14.1 to 14.3 lb/gal. The density can be increased to 15.1 lb/gal by adding calcium chloride flakes or pellets. Care must be taken for cold weather formulation by mixing proper amounts of calcium chloride and calcium bromide to maintain the solution above its freezing point during cool weather.

High-pressure drilling, workovers, and completion operations occasionally necessitate using densities to 19.2 lb/gal. Adding calcium chloride and calcium bromide to a zinc bromide solution can achieve a density of 19.2 lb/gal. Various concentrations of the three salts, in addition to other special products, can be used to formulate summer and winter blends.

Charts and tables for brine-water formulation are given in the Appendix. Example 8.1 shows a sample calculation for preparing CaCI2 brine. Metric

Clay Hydration

ION DIAMETER, A° Hydration Energy not hydrated hydrated* kcal/mot

124.4

97.0

77.0

2.16

377 459,1

72.5

*There is some variation in the figures for hydrated ion diameters found in the literature.

Fig. 8-7 Potassium ion sizing minimizes clay hydration (Courtesy NL Baroid)

material requirements for preparing CaCl, are given in the Appendix. Table B5 gives the composition of 1 bbl of sodium chloride/calcium chloride mixed brine.

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Responses

  • Gabriella
    How to mix CaCl2/CaBr brine?
    8 years ago
  • fiori
    How to use calcium chloride brine charts for drilling mud?
    8 years ago
  • nathanial
    When is chlorine used in drilling operations?
    7 years ago
  • nuguse omar
    Is brine used in the oil field Cacl or NaCl?
    8 months ago
  • fosca
    What is the chloride content of 10 lb brine?
    6 months ago
  • Anthony
    What is the salt lb/bbl for 10.0 ppg nacl brine?
    4 months ago
  • Leigh
    Is zinc chloride a completion brine?
    3 months ago
  • Virgilio
    What is the lowest effective operating temp of brine fluids?
    3 months ago

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