The Jurassic sandstone reservoirs in western Sichuan Depression are mainly of delta distributary channel depo-sits

featuring in tightness and low permeability.The channel sands are complex invertical superimposition

small in thickness

and large in variations of lithology and poroperm characteristics.It is difficult to predict and characterize those reservoirs due to the limited seismic resolution

constraining target evaluation and well pattern deployment.A comprehensive method was adopted to study the reservoirs from macroscopic to microscopic observation

from qualitative to quantitative analysis and from appearance description to internal heterogeneity evaluation.Several key techniques were proposed

including channel sedimentary sequence identification

forward modeling of stacked channel sands

description of space distribution of facies and quantitative characterization of reservoirs based on progressive inversion.They were successfully used in subdivision of channel sequence

prediction of stacking pattern and quantitative description of appearance

making it possible to perform fine evaluation of development target with single channel as an appraisal unit.A technology system was established for fine description and characterization of continental channel sands in tight-gas reservoirs.