Productivity Prediction Of Gas Well Based On The Affect Of Threshold Pressure Gradient

The research of gas well productivity is the basis of determining producing method and optimizing production parameters. The research of threshold pressure gradient is significant for productivity prediction of gas well. Based on the research of gas well productivity and threshold pressure gradient at home and abroad, forecasting model of gas well productivity is optimized using field document. The affecting factors of gas well productivity are analyzed, for example formation capacity, formation pressure, radius of gas well, aeolotropism, non-Darcy coefficient, skin factor, gas drainable radius, gas viscosity, deposition of sulfur, water lock, sand composition, depositional environment, diagenetic facies and so on. Formation capacity is a dominant factor which affects gas well productivity. Based on the office study of threshold pressure gradient, the influence of threshold pressure gradient on gas well productivity is analyzed in low permeability gas reservoir. Productivity prediction models of fractured well and horizontal well are derived under the influence of threshold pressure gradient. The software is compiled which is used to forecast gas well productivity. The experiment study and example analysis indicate that slippage effect and threshold pressure gradient are all existent. When effective permeability of gas reservoir increases, threshold pressure gradient decreases on the condition that bound water saturation is existent. But threshold pressure gradient increases along with increasing water saturation of core. AOF and recovery ratio are all less than that when threshold pressure gradient is absent. The findings are significant for dynamic analysis in gas reservoir.