| 摘要 |
The invention provides oil base well drilling and servicing fluids (OBWDSF) containing a hydrophilic tannin to decrease the fluid loss of the OBWDSF. The hydrophilic tannin, which may be sulfited, is preferably selected from the group consisting of quebracho, wattle, and mixtures thereof. The OBWDSF will contain from about 50% to about 100% by volume of a continuous oil phase, and generally will contain up to about 50% by volume of a discontinuous, emulsified aqueous phase. The OBWDSF can also contain other fluid loss control additives other than the hydrophilic tannin, preferably selected from the group consisting of resins, synthetic polymers, Gilsonite, organophilic polyphenolic compounds, and mixtures thereof. The invention also provides a method of decreasing the fluid loss from an OBWDSF which comprises incorporating into the OBWDSF a hydrophilic tannin. |
