The problems of strong longitudinal heterogeneity and difficulties in fine evaluation exist in shale reservoirs from the Wufeng Formation to the first member of Longmaxi Formation in Weirong Shale Gas Field.Therefore

TOC content

gas content

proportion of organic pores

brittle mineral content

clay mineral content

brittleness index and horizontal stress difference coefficient are selected as the key parameters for the shale gas reservoir evaluation

and the gray correlation analysis method is applied to quantitatively characterize reservoir quality based on the characteristics of Weirong deep shale gas reservoirs and their main influencing factors.The results show that:① By calculating the correlation between evaluation parameters and reservoir quality

it is clear that gas content is the primary parameter to indicate high-quality reservoir.②By calculating the comprehensive evaluation index of reservoir quality（Q）

the reservoir can be divided into four levels

among which the A-level one is mainly biosiliceous shale and calcium-bearing-clay-siliceous shale

consisting with the target window position of the current horizontal wells

and the research results are in good agreement with development practices.This method realizes the fine evaluation of reservoir quality under the influence of multiple factors

provides the basis for the objective evaluation of high-quality shale reservoirs

and has reference significance for the evaluation and development of similar gas reservoirs.