Calculation methods of dynamic reserves of tight gas wells in Changqing oilfield

Gas wells of Changqing oilfield were generally characterized by low permeability reservoirs,lack of pressure test data,unsteady working schedule and large amount of gas wells,the traditional appraising method was difficult to accurately evaluate dynamic reserves of gas wells in time.By considering characteristics of production and fluid mechanics in Changqing gas field,apractical dynamic reserves appraising method,which was based on superposition theory,was proposed.With merits of introducing superposition time into dynamic reserves equation of tight gas,this simplified method was useful to deal with variable rate without relying on typical curve fitting.Besides,the result of this method was correct and unique.Furthermore,a technical support was provided to realize quick estimation of dynamic reserves in Changqing gas field.