Production Decline Analysis Method And Its Application In Tight Gas Reservoirs

The production evaluation and analysis of tight gas reservoirs are the key and difficult points in the development and adjustment of tight gas reservoirs.In this paper,the decreasing analysis method for the single-layer and multi-layer fractured wells and the elliptical seepage model of acid factured well wells in in tight sandstone and carbonate gas reservoirs were studied.The models were solved by gas reservoir pseudo-pressure,perturbation theory,numerical inversion and other methods,and the unstable pressure and yield characteristics were drawn.Then,this paper made the sensitivity analysis of the plate by changing the boundary radius,stress sensitivity coefficient,composite radius,matrix storage ratio of dual-medium gas reservoir,turbulence coefficient,layered formation coefficient ratio of multilayer gas reservoir,and stratified storage ratio.The production decline process of multi-layer wells is controlled by the boundary of the model.The pressure and production of the gas wells would exhibit different mixing characteristics in the pseudo-steady state by the combination of different boundaries.The unsteady period of stratified production of gas reservoir is proportional to the formation coefficient and the conductivity of artificial fracture.The pseudo-steady state is proportional to the layer storage capacity.In view of the large fluctuations in the multi-layer gas reservoir production test,the calculation method of the production section is used to improve the profile test data,and the relatively stable production profile is obtained.At the same time,based on the catastrophe theory,the introduction of the catastrophe theory is introduced.The sedimentary correction coefficient of multi-layered features is established,and the mathematical system of multi-layer gas reservoir production in the multi-objective system is established.Finally,the unstable pressure and production decline model of fractured wells and acid fractured wells are applied to Daniudi tight gas reservoirs and Western Sichuan carbonate tight gas reservoirs,which got a better interpretation of the results.The improved production splitting method were applied to the 36 multi-layer well in Daniudi gas reservoir,and the parameters such as stratified dynamic reserves were calculated,which provided dynamic adjustment for the development of tight gas fields.