High density clear brine fluids

Abstract

Compounds are identified that act as crystallization suppressants when added to clear brine fluids, significantly lowering the true crystallization temperatures of the brines, and allowing for higher salt content in clear brine fluids. The crystallization suppressants of the invention also allow for the preparation of higher density zinc free brines.

What is claimed: 
     
         1 . A method for lowering the true crystallization temperature of a clear brine fluid comprising a halide salt and water and having a density of at least 9 ppg, which method comprises adding from 2 to 20 wt %, based on the combined weight of the halide salt and water, of a crystallization suppressant additive comprising an aldose or ketose having at least 4 carbon atoms, an oligosaccharide compound, an alditol having at least 3 carbon atoms or a 1,3 dicarbonyl compound having from 3 to 7 carbon atoms. 
     
     
         2 . The method according to  claim 1  wherein the halide salt is a chloride or bromide salt of sodium, potassium or calcium, and the clear brine fluid comprises less than 1 ppm of zinc or cesium. 
     
     
         3 . The method according to  claim 1  wherein the crystallization suppressant additive comprises an aldose or ketose having from 4 to 6 carbon atoms, an alditol having from 3 to 6 carbon atoms or a malonamide having from 3 to 7 carbon atoms. 
     
     
         4 . The method according to  claim 3  wherein the crystallization suppressant additive comprises an alditol having from 3-6 carbon atoms or a malonamide having from 3 to 7 carbon atoms. 
     
     
         5 . The method according to  claim 1  wherein the crystallization suppressant additive comprises a mixture of two or more compounds selected from the group consisting of aldoses or ketoses having at least 4 carbon atoms, alditols having at least 3 carbon atoms, and 1,3 dicarbonyl compounds having from 3 to 7 carbon atoms. 
     
     
         6 . The method according to  claim 2  wherein the crystallization suppressant additive comprises an aldose or ketose having from 4 to 6 carbon atoms, an alditol having from 3 to 6 carbon atoms or a malonamide having from 3 to 7 carbon atoms. 
     
     
         7 . The method according to  claim 6  wherein the crystallization suppressant additive comprises an alditol having from 3-6 carbon atoms or a malonamide having from 3 to 7 carbon atoms. 
     
     
         8 . The method according to  claim 1  wherein the clear brine fluid has a density of at least 12 ppg. 
     
     
         9 . The method according to  claim 2  wherein the clear brine fluid has a density of at least 12 ppg. 
     
     
         10 . A clear brine fluid having a density of at least 10 ppg, comprising water, a halide salt and from 2 to 20 wt %, based on the combined weight of the water and halide salt, of an aldose or ketose having at least 4 carbon atoms, an alditol having at least 3 carbon atoms or a 1,3 dicarbonyl compound having from 3 to 7 carbon atoms. 
     
     
         11 . The clear brine fluid according to  claim 10  wherein the halide salt comprises a chloride or bromide salt of sodium, potassium or calcium, and the clear brine fluid comprises less than 1 ppm of zinc or cesium. 
     
     
         12 . The clear brine fluid according to  claim 10  wherein the aldose or ketose has from 4 to 6 carbon atoms, the alditol has from 3 to 6 carbon atoms and the 1,3 dicarbonyl compound is a malonamide. 
     
     
         13 . The clear brine fluid according to  claim 11  wherein the aldose or ketose has from 4 to 6 carbon atoms, the alditol has from 3 to 6 carbon atoms and the 1,3 dicarbonyl compound is a malonamide. 
     
     
         14 . The clear brine fluid according to  claim 12  comprising water, the halide salt, and from 2 to 20 wt %, based on the combined weight of the water and halide salt, of an alditol having from 3-6 carbon atoms or a malonamide having from 3 to 7 carbon atoms. 
     
     
         15 . The clear brine fluid according to  claim 13  comprising water, the halide salt, and from 2 to 20 wt %, based on the combined weight of the water and halide salt, of an alditol having from 3-6 carbon atoms or a malonamide having from 3 to 7 carbon atoms. 
     
     
         16 . The clear brine fluid according to  claim 10  comprising a mixture of two or more compounds selected from the groups consisting of aldoses or ketoses having at least 4 carbon atoms, alditols having at least 3 carbon atoms, and 1,3 dicarbonyl compounds having from 3 to 7 carbon atoms. 
     
     
         17 . The clear brine fluid according to  claim 10  wherein the clear brine fluid has a density of at least 12 ppg. 
     
     
         18 . The clear brine fluid according to  claim 11  wherein the clear brine fluid has a density of at least 12 ppg. 
     
     
         19 . A clear brine fluid having a density of at least 10 ppg, comprising water, a halide salt and an oligosaccharide compound. 
     
     
         20 . The clear brine fluid according to  claim 19  further comprising one or more of an aldose or ketose having at least 4 carbon atoms, an alditol having at least 3 carbon atoms or a 1,3 dicarbonyl compound having from 3 to 7 carbon atoms.