Patent ID: 7833946
Filing Date: 2010-11-16
Classification: C09K

Abstract:
1. A water based drilling fluid containing as additive two alkyl ethoxylates having the formula RO(CH 2 CH 2 O) n H and different hydrophilic-lipophilic balance values; wherein: R is a C n is an integer in the range 2-30; the fluid further containing one or more viscosifying agents, and being clay-free; the alkyl ethoxylates have a combined hydrophilic-lipophilic balance value of less than 9; and the concentration in g/l of the alkyl ethoxylate with a lower hydrophilic-lipophilic balance value is at least 1.5 times greater than the concentration in g/l of the alkyl ethoxylate with the higher hydrophilic-lipophilic balance value.