Abstract: The Koulele Oilfield in the Termit Basin of Niger is rich in oil and gas resources. Accurate prediction of the spatial distribution of sand bodies can provide a geological basis for subsequent reservoir exploration and development. By comprehensively utilizing core，well logging，and 3D seismic data，and based on the analysis of paleotopography and sediment supply conditions，combined with modern sedimentary comparisons，the depositional characteristics of the late Eocene shallow-water delta front in the study area were summarized and a depositional model was established. The results show that:（1）During the deposition period of the E1 oil formation in the late Eocene of the Koulele Oilfield in the Termit Basin of Niger，the terrain was flat with a gentle slope and abundant sediment supply. Mainly shallow-water delta front deposits and typical tractional current depositional structures developed，with lithologies dominated by siltstone to fine sandstone and mudstone. The well logging curves are mainly characterized by five types: box-shaped，bell-shaped，finger-shaped，funnel-shaped，and straight，with box-shaped and bell-shaped curves accounting for more than 70%. On seismic slices，the sand bodies appear as branch-like strips and contiguous lobe-shaped features. Lenticular reflection characteristics of channel fills can be observed on cross-sections，with no obvious progradational features. The sand body thickness map predicted by seismic intelligent fusion inversion exhibits single finger-like extensions，some of which are branchlike strips with bifurcating ends that develop into contiguous lobe-shaped features，similar to the morphology of modern finger-bar deltas.（2）The distribution and evolution characteristics of sedimentary microfacies vary at different times in the study area. In the early deposition stage of the E1 oil formation，river channels were mostly single-finger shaped with low curvature. Mouth bars developed in a lobe shape at the ends of river channels，with a relatively small scale，a width of less than 100 m，a thickness of 2 to 3 m，and a limited extension. In the middle deposition stage of the E1 oil formation，the scales of river channels and mouth bars increased，and branching phenomena occurred in the river channels. In the late deposition stage of the E1 oil formation，the scales of river channel and mouth bar sand bodies reached their maximum，with high curvature river channels distributed in a branching strip shape and bifurcating ends，and mouth bars distributed contiguously.（3）Overall，finger-like channel sand bodies are more developed in the inner delta front of the study area，while contiguous lobe-shaped mouth bar sand bodies are more developed in the outer delta front. Along the sediment source direction，the development scale of mouth bars gradually increases，while the development degree of river channels decreases. River channels undercut mouth bars，presenting a pattern of“rivers running over bars”. Vertically，the sand bodies are superimposed and developed.

Key words: sedimentary characteristics, shallow-water delta, branch-like strips sand, contiguous lobe-shaped sand, finger bar, Eocene, Koulele Oilfield, Termit Basin, Niger