�?�?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 paper will go over the next main subjects: Deep perfectly drilling systems are of vital importance within the drilling field. In this process, the drilling fluid (drilling mud) is used to take care of stress balance, neat the dr