�?�?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 natural fractures encountered in the actual drilling method usually are not parallel fractures that has a uniform width alongside the duration with the fracture. In the course of the loss system, when the fluid stress during the