�?�?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 The lower in annular return move will trigger the circulation velocity of drilling fluid inside the annulus https://swiss-directory.com/listings1151254/how-drilling-mud-loss-can-save-you-time-stress-and-money