Evaluation of fracability and screening of perforation interval for tight sandstone gas reservoir in western Sichuan Basin

The western Sichuan tight sandstone gas reservoir is characterized by low porosity, ultra-low permeability, and shale interbedding. The most effective way to exploit this formation would be large-scale hydraulic fracturing. Currently, however, no appropriate method exists for selecting fracturing candidates to maximize the scale of the complex hydraulic fracture system. Therefore, fracability should be evaluated when developing this type of reservoir. In this study, fundamental mechanical experiments are performed to determine the correlation between fracability and its influencing factors. Based on the experimental results, reservoir fracability is evaluated using a new model that integrates all of the related factors. Formations with high fracability are selected as hydraulic fracturing candidates, and a new method for selecting perforation intervals is proposed based on the determined reservoir fracability. As case studies, the appropriate perforation intervals are examined for two wells drilled in the western Sichuan Basin: vertical well XC32 and horizontal well HF-1.