abstract |
A water based drilling fluid contains as additive one or more alkyl ethoxylates having the formula RO(CH 2 CH 2 O) n H; n wherein: n R is a C 16-22 alkyl group (preferably R is aliphatic and more preferably R is linear), and n n is an integer in the range 2-30. n The fluid further contains one or more viscosifying agents, and is substantially clay-free. |