The model for deliverability of gas well with complex shape sand bodies and small-scale reserve of Sulige Gas Field in China

Because of the complex shape sand bodies of Sulige Gas Field, gas well controlled reserves is low, and reservoir pressure drop fast, it is very hard to accurately forecast gas well deliverability. Based on the study of characteristics of sand bodies, four superimposed sand models and a two-region seepage model are put forward. Using the material balance method of natural water drive gas reservoir and cumulative production methods to calculate dynamic reserve of near wellbore I and distant wellbore II and cumulative gas invaded volume from distant wellbore II. Boundary reservoir pressure was calculated by the iteration in different production periods, and the deliverability model was established based on gas deliverability equation of pseudo-stationary flow in gas well of complex shape sand bodies and small-scale reserve in Sulige Gas Field. The model considers not only distribution characteristics of reservoir pressure in different seepage modes, but also fast dropping of reservoir pressure. The application shows that the result is accurate, the mean error being below 10 % and the model can meet the requirement of the project.