摘要 |
Hydroxyethyl cellulose and a sequestrant are added to a heavy brine containing one or more salts selected from calcium chloride, calcium bromide, and zinc bromide to increase the viscosity of the brine. Preferably the brine contains zinc bromide, has a density in the range from about 14.2-19.2 pounds per gallon, and the sequestrant is a polyphosphonic acid or water soluble salt thereof.
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