Tight Gas Reservoir Characteristics and Well Classification Evaluation of Shaximiao J2s2 Formation in JQ Block, Tianfu Gasfield, Sichuan Basin

The Shaximiao J2s2 gas reservoir in JQ Block, Tianfu gasfield, Sichuan Basin has poor physical properties, strong heterogeneity, and low recoverable reserve. Conventional logging interpretation results does not clearly identify high production formations, making it difficult to effectively carry out gas reservoir classification and evaluation. According to the development characteristics of horizontal wells in gas reservoirs, based on the analysis of electrical and physical properties, new evaluation indicators such as effective seepage area of artificial fractures and gas production rate in horizontal sections are introduced. Based on the development performance differences between vertical and horizontal wells, methods such as analogy analysis and equivalent evaluation of horizontal wells are used to comprehensively determine the evaluation indicators. Using fuzzy mathematics and Analytic Hierarchy Process (AHP) method, a comprehensive evaluation system for horizontal well development is constructed, and the actual productivity of production wells is compared with the evaluation results. It is believed that the comprehensive evaluation method for gas reservoirs is reliable and can effectively guide the development of vertical and horizontal wells.