Abstract: Establishment of shale gas evaluation criteria and reservoir classification methods is important for shale gas exploration and development.Based on investigation and survey of geological features,gas generating capacities,gas storage capacity and recoverability of typical shale gas plays in the world,10 parameters for shale gas reservoir evaluation were selected in combination with the specific geological conditions of Sichuan Basin and their scores for shale gas reservoir classification were also determined.Grey relational analysis method was used to define the relationship between these factors and to calculate the weights of the principle and secondary factors and the comprehensive evaluation factors of shale gas reservoir quality.Shale gas reservoir classification was further performed on the calculation results.Shale gas reservoirs in Sichuan Basin are similar with that in the 5 major shale gas basins in the America.The comprehensive evaluation factors of shale gas reservoirs in the Longmaxi Formation and Qiongzhusi Formation are 0.48 and 0.45 respectively,which are very close to that of New Albany shale gas basin.Case study shows that the reservoir classification results accord well with the practical production situation.This evaluation method can be applied to shale gas reservoir evaluation and selection in China.

Key words: index score, main factor, weight coefficient, evaluation index, comprehensive evaluation factor, reservoir classification, shale gas