�?�?t ρ l k + �?�?x i ρ l k v l = �?�?x j μ + μ t σ k �?k �?x j + G k �?ρ l ε �?Y M Although preferred, stopping lost circulation totally is not really often achievable or required. Controlled losses enable drilling to continue when holding the wellbore complete, protecting against an inflow of gasoline or fluid in