Abstract: In order to illustrate the lithologic heterogeneity characteristics and spatial-temporal distribution of oil shale of the 2^nd Member of Funing Formation in Qintong sag,Subei Basin,this paper makes research on lithology heterogeneity of shale through cores,well logging,geochemical tests and 3D seismic data.After analyzing rock type,well logs,TOC and mineral contents,the oil shale is divided into black shale,silty mudstone and lime mudstone.After the research on lithology division and isochronous sequence stratigraphic framework,Facies and Fluids Probabilities(FFP)method is used to predict the spatial-temporal distribution of various lithologies within the oil shale,and the prediction results are confirmed by the real logging data.The results indicate that in the early expansion system tract,lime mudstone widely deve-loped in the research area,meanwhile silty mudstone only developed in the southwest of Qintong sag.With the lake level rising,lime mudstone developed in the central sag and silty mudstone developed in the southwest and northeast of the sag.Black shale deposited in the entire area.In the late expansion system tract,black shale was widely deposited in the sag,while lime mudstone developed sporadically and silty mudstone only developed in the southwest and northeast of the sag.In conclusion,FFP can accurately predict the temporal and spatial distribution of various lithologies within oil shale,which has important significance for the exploration and development of oil shale.

Key words: heterogeneity, facies and fluids probabilities(FFP), oil shale, Funing Formation, Qintong sag