CPC C09K 8/035 (2013.01) [C09K 8/04 (2013.01); C09K 8/06 (2013.01); C09K 8/58 (2013.01); C09K 8/86 (2013.01); E21B 43/16 (2013.01); C01F 11/24 (2013.01); C01F 11/34 (2013.01); C01G 9/04 (2013.01); C01P 2006/22 (2013.01); C09K 2208/34 (2013.01)] | 12 Claims |
1. A divalent brine based downhole treatment fluid comprising:
about 10 to about 18 pounds per gallon of a divalent brine comprising calcium bromide, calcium chloride, zinc bromide, zinc chloride, or a combination comprising at least one of the foregoing;
a rheological modifier present in an amount effective to improve the rheological properties of the divalent brine based downhole treatment fluid at a temperature of greater than about 200° F., the rheological modifier comprising a phosphate ester blended with an ethoxylated glycol, and the divalent brine based downhole treatment fluid comprising about 0.5 to about 4 pounds of the rheological modifier per barrel of the divalent brine based downhole treatment fluid; and
a pH stabilizer comprising a diamine,
wherein the phosphate ester is a hydrocarbyl polyether phosphate ester optionally comprising one or two hydroxyl groups directly attached to phosphorus,
the ethoxylated glycol comprises ethoxylated ethylene glycol, ethoxylated propylene glycol, ethoxylated glycerin, ethoxylated polyethylene glycol, ethoxylated polypropylene glycol, or a combination comprising at least one of the foregoing, and
the divalent brine based downhole treatment fluid has a pH of greater than about 7.5.
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