Study on unsteady seepage characteristics and EUR evaluation methods of tight channel sandstone gas reservoirs

Tight channel sandstone gas reservoirs have the characteristics of strong heterogeneity, low porosity and permeability, and slow formation energy supply in the later stage of mining. In the process of gas well development, the initial production deceleration rate is fast, the later production deceleration rate is slow, and the EUR prediction result is large in error. In response to the above problems, this paper starts from the perspective of seepage mechanics, establishes a EUR evaluation mathematical model, derives the staged fractured horizontal well pressure response model and productivity model, predicts future production performance based on the production instability method, and uses Topaze The production analysis software adopts the method of production instability analysis to simulate and analyze the single well controlled reserves at different production times in stages, which further confirms the change process. The research results of this paper have certain guiding significance for predicting and analyzing single-well EUR.