| 摘要 |
There is provided a wellbore fluid having a continuous aqueous phase, and comprising at least one polymer which: - has a molecular weight in the rang e of from 2,000 to less than 100,000; contains hydrophilic units such that t he polymer is at least 2 % soluble in water at 20 øC, and such that less tha n 50 % by weight of said hydrophilic units comprise -CH2-CH2O- units; and co ntains pendant alkyl groups having at least 10 carbon atoms, the combined mo lecular weight of said pendant alkyl groups being in the range of from 15 to 70% by weight based on the weight of the polymer. Such aqueous based wellbo re fluids exhibit significantly improved fluid loss properties when used in wellbore operations, such as drilling, completion or workover.
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