| 摘要 |
Methods are provided for treating a portion of a well and include the steps of: (a) forming a treatment fluid comprising an aqueous solution, wherein the aqueous solution comprises: (i) water; (ii) a water-soluble polysaccharide; (iii) one or more water-soluble salts, wherein the one or more salts are selected and are in at least a sufficient concentration such that the water-salt solution has a density of at least 10 ppg; and (iv) urea; and (b) introducing the treatment fluid into the portion of the well. According to the inventions, the concentration of the urea in the water is in at least a sufficient concentration such that aqueous solution: (1) has a G′ of at least 2 Pa, or (2) is filterable. According to the inventions, an identical aqueous solution except with less than the sufficient concentration of the urea would not satisfy the above conditions.
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