A method is provided for controlling the delay time of aqueous borate-crosslinked polysaccharide-based fluids for hydraulic fracturing and related applications which allows on-the-fly control of the delay time without comprising overall fluid integrity. Without having to modify the t
The present invention extends the temporary temperature range for the use of magnesium oxide-delayed borate-cross linking of a galactomannan gum fracturing fluid by adding fluoride ion which precipitates insoluble magnesium fluoride. Alternatively, a chelant for the magnesium ion may be
