�?�?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 paper will go over the subsequent principal subject areas: Deep nicely drilling technologies are of essential value inside the drilling field. In this method, the drilling fluid (drilling mud) is used to maintain stress