�?�?t ε l ρ l v l + �?�?ε l ρ l v l v l = ε l �?�?τ l + ε l ρ l g �?ε l �?p �?β v l �?v s The reduce in annular return flow will trigger the circulation pace of drilling fluid within the annulus to reduce, along with the friction amongst it and the annulus will lower, Hence the BHP and standpipe strain will mini