| 摘要 |
The invention relates to an additive based on a polyalkylene imine and a sulfonated formaldehyde-containing condensation product, and the use thereof as a fluid loss additive for the cementing of boreholes in the fields of crude oil and natural gas. Typical representatives of polyalkylene imines are polyethylene imine, polypropylene imine, and polybutylene imine, which can also be derivatised. Preferred condensation products are acetone/formaldehyde resins. Such additives which are left to ripen before being used, especially by being allowed to stand, have an especially low fluid loss value.
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