Weight Up of Single Salt Brine with Dry Chemicals
When single salt brines become diluted with water, they can be reconstituted to their original composition by adding dry or crystalline chemicals to the diluted brine, provided sufficient mixing equipment is available. Reference information showing the weight percent contained at different densities (pctf and pctdil) can be found in the density and composition tables in Chapter 6 in the section titled, "Single Salt Fluid Composition and Blending Tables."
EQUATION 12.
Whenever dealing with dry chemicals, it is important to make sure you know the purity or percentage of pure salt contained in the product with which you are working. One to five percent water and impurities are not uncommon in technical grade chemicals. To calculate total product, divide the pounds of 100% compound (lbpure) in Equation 12 by the purity percentage to increase the total product added to the recipe as illustrated in Equation 13.
EQUATION 13.
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Make sure you know the purity or percentage of pure salt contained in the product with which you are working. |
Weight Up Tables
For a quicker way to determine the amount of weight material required for a density increase of a single salt brine by as much as 0.6 lb/gal, weight up tables, similar to the following one (Table 10), are provided in Chapter 6. They are organized by fluid type and density in the section titled, "Single Salt Fluid Composition and Blending Tables."
In Table 10, as well as in all of the weight up tables in Chapter 6, column one provides starting density and the succeeding columns provide information for the pounds of dry salt of stated purity (in this case 99%) required to achieve a density increase of 0.1 lb/gal to 0.6 lb/gal. There will be a volume increase using this method, which is discussed in the text below Equation 14.
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Remember that using dry chemicals in a weight up can result in a substantial temperature increase. A bench scale pilot can give an indication of how hot the fluid is likely to become. Always add dry chemicals slowly. |
TABLE 10. Sodium Chloride (NaCl) Weight Up Table (lb/bbl)
Weight Up Using 99% Information |
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| Starting Density |
Weight Up Increments (0.1 lb/gal) | |||||
| 8.4 | 4.92 | 11.91 | 17.96 | 24.06 | 31.33 | 37.58 |
| 8.5 | 6.98 | 13.01 | 19.10 | 26.36 | 32.59 | 38.89 |
| 8.6 | 5.99 | 12.03 | 19.23 | 25.42 | 31.67 | 39.15 |
| 8.7 | 6.01 | 13.18 | 19.34 | 25.56 | 33.00 | 40.57 |
| 8.8 | 7.13 | 13.26 | 19.44 | 26.86 | 34.39 | 42.04 |
| 8.9 | 6.08 | 12.22 | 19.58 | 27.05 | 34.64 | 41.11 |
| 9.0 | 6.11 | 13.43 | 20.86 | 28.42 | 34.86 | 42.63 |
| 9.1 | 7.28 | 14.68 | 22.20 | 28.61 | 36.34 | 44.20 |
| 9.2 | 7.34 | 14.80 | 21.15 | 28.83 | 36.63 | 44.56 |
| 9.3 | 7.40 | 13.70 | 21.32 | 29.05 | 36.92 | 44.92 |
| 9.4 | 6.25 | 13.80 | 21.48 | 29.28 | 37.22 | 45.29 |
| 9.5 | 7.51 | 15.15 | 22.91 | 30.81 | 38.84 | |
| 9.6 | 7.57 | 15.28 | 23.11 | 31.07 | ||
| 9.7 | 7.64 | 15.40 | 23.30 | |||
| 9.8 | 7.70 | 15.53 | ||||
| 9.9 | 7.77 | |||||
Dry Salt Weight Up Volume Increase
The weight up tables like Table 10 and those provided in Chapter 6 assume that you are starting with one barrel of brine and will be adding dry salt to increase the density.
EQUATION 14.
Suppose you want to increase the density of an 8.8 lb/gal (d1) NaCl brine to 9.1 lb/gal (d2), a 0.3 lb/gal increase. This would require 19.44 lb of 99% NaCl (from Table 10) per barrel of starting brine. Applying Equation 14 above, shows that the volume would increase to 1.018 bbl, or 1.8 bbl per 100 bbl of starting brine treated.
EXAMPLE H. Weight Up of Single Salt Working Fluid with Dry Salt
