A trilinear flow model is one of the common methods solving the well test models for the multistage fractured horizontal wells. By the orthogonal test

the range analysis method and the variance analysis method

we analyzed the influence of the half fracture length

the half reservoir thickness

the width of the inner zone

the dimensionless fracture conductivity and the permeability in inner zone on the double log curves fitting of the pressure and the pressure derivative of the trilinear flow model and numerical model. According to this analysis

the factors affecting the curves of the pressure characteristic curves of two models ranged from more to

less are the dimensionless fracture conductivity(F

CD

)

the permeability in inner zone（k

I

）

the half fracture length（x

f

）

the half reservoir thickness（x

e

）and the width of inner zone（y

e

）. The fracture conductivity affect obviously on the fitting of the pressure characteristic curves of two models. When the fracture conductivity is less than 1

the curve fitting effect is poor

so the linear flow model is not applicable. Otherwise

when the fracture conductivity is greater than 1

the curve fitting effect is good

so the linear flow model is suitable.