Abstract: The Arps equation involves exponential decline, hyperbolic decline and harmonic decline, in which the hyperbolic decline equation is widely used and can be solved in many methods. Their results are similar and reliable for oil and gas reservoir, which production strictly follows decline type.However,the difference of solutions is remarkable if reservoirs and wells do not strictly obey the decline type.To solve the problem,a pure non-linear model is developed on the basis of the Arps hyperbolic decline

Key words: production decline, nonlinear, cure fit, analytic model