| 摘要 |
It has been discovered that aminocarboxylic acids are effective breakers for polymer-gelled aqueous fracturing fluids, particularly in the temperature range between about 120°F (49°C) and about 280° F (138°C). The aminocarboxylic acids are believed to act directly on the polymer and not to any great extent or not to as an effective extent on a crosslinking agent, if present. The polymer may be a polysaccharide, and the aminocarboxylic acid may be selected from the group including, but not necessarily limited to, tetrasodium ethylenediaminetetraacetic acid (Na 4 EDTA), tetrasodium propylenediaminetetraacetic acid (Na 4 PDTA), trisodium hydroxyethylenediaminetetraacetic acid (Na4HEDTA), trisodium nitrilotriacetic acid (Na 3 NTA), salts of these acids, and mixtures thereof.
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