Calculation method and application of operational dynamic parameters of the edge-water gas reservoir gas storage
The traditional material balance method based on the"tank"concept cannot quantitatively calculate the residual gas loss volume during gas production stage in the water invasion zone in the gas storage,nor can it quantitatively analyze the change laws of operational dynamic parameters of working wells during the edge-water unsteady water intrusion process.In order to solve this problem,this research firstly establishes an improved material balance equation considering the residual gas volume in the water intrusion zone,and based on this equation,an analytical model of the key operational dynamic parameters of the working well during gas production is derived according to the gas-water unsteady seepage theory.Then,using the base data of a working well in a certain edge-water gas reservoir gas storage,the variation pattern of the operational dynamic parameters during gas production stage is quantitatively analyzed and the calculated results are compared and verified.Finally,the characteristics and applicability of the calculation method are discussed.The research shows that this method can quantitatively analyze the variation pattern of time-varying well control parameters during unsteady water intrusion in the edge-water gas reservoir gas storage,grasp the pressure variation characteristics of different zones,quantify the residual gas volume in the water intrusion zone,and specify the effective well control storage capacity of working wells.The results of the operational dynamic parameter calculation show that as the production time increases,the time-varying well control radius gradually decreases and the residual gas volume in the water intrusion zone gradually increases.Under the same water intrusion volume,compared to the late stage of gas production,the increase of time-varying well control parameters and the residual gas loss are smaller in the initial stage of gas production,reflecting the transformation process of gas production energy in the gas storage from being mainly driven by elastic energy in the early stage to relying on the supplementary energy of the edge-water to produce gas in the late stage.The research results have clear practical significance and value for the investigation of the operation rules of similar edge-water gas reservoir gas storage,the analysis of storage capacity parameters and operation dynamics,and the formulation of a reasonable working system for working wells.
edge-water gas reservoirgas storageoperation dynamicsunsteady water intrusionresidual gas volumewell control storgae capacity
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