Weibull

HCZ and Logistic models are widely used to forecast output of oil/gas fields.They are only suitable for oil/gas fields in middle or late stage of development and in declining.However

they are not applicable to fields in early development stage due to the shortage of production data.In this paper

the calculation methods of parameters are improved for obtaining the parameters of these models with the limited data in the early stage of development.In this way the range of application of these production forecast models can be extended for use in the early stage of development.In addition

methods of model optimization are also presented to provide a basis for choosing the proper model for production forecast of different oil/gas fields.