Optimal selection design method for repeated fracturing index confidence coefficient horizon

The invention relates to a repeated fracturing index confidence coefficient horizon optimization design method. After primary fracturing and production, a crustal stress model before repeated fracturing is obtained through four-dimensional geomechanical calculation; the method comprises the following steps: collecting field initial pressure data and production data, and constructing a refracturing database comprising geological parameters, initial pressure fracturing construction parameters and dynamic production system parameters; a shale reservoir refracturing evaluation system is obtained after construction is completed, and normalization processing is conducted on parameters; carrying out uncertainty characterization on related parameters influencing the refracturing effect index; and on the basis of a refracturing model established by an entropy weight method, reservoir refracturing parameter distribution containing confidence is obtained, a reliability theory is utilized, and according to ideal well par