The shale gas reservoirs of the Wufeng-Longmaxi Formations in the Fuling shale gas play

the eastern Sichuan Basin have been put into commercial production.In the first-phase development block

the single well productivities show a great difference and the gas storage varies laterally

but the causes are still poorly understood.The previous geological evaluation indicated that the lateral distributions of the primary reservoir qualities like shale thickness

mineral composition

and organic carbon content are stable

thus could not be the key factors affecting gas storage.Instead

the variation of gas storage may be closely related to structural deformation.Starting with the characterization of regional structural deformation

this paper presents a systematical research on the structural features

tectonic framework and structural styles in the study area.The study area experienced multi-stage tectonic movements

resulting in multi-level decollement structures

which can be vertically divided into 3 structural deformation layers and 7 structural styles

with an obvious difference in structural deformation intensity.A preliminary quantitative characterization of the structural deformation intensity shows that the fault throw

formation thickening ratio

curvature and fault density are the key parameters for characterizing the structural deformation intensity of the study area.Based on the quantitative characterization

four structural deformation areas are recognized in the study area

and they have significantly different gas storage

indicating that the structural deformation intensity is the key factor causing the variation of gas storage in the study area.