摘要 |
<p>A water based drilling fluid contains as additive one or more alkyl ethoxylates having the formula RO(CH2CH2O)nH; wherein: R is a C16-22alkyl group (preferably R is aliphatic and more preferably R is linear), and n is an integer in the range 2-30. The fluid further contains one or more viscosifying agents, and is substantially clay-free.</p> |