Abstract: Laminated shale oil in the Chang 7₃ Member of the Ordos Basin mainly occurs in the multi-lithologic composite strata at the bottom of the source rock, with a stratigraphic thickness of 5-20 m. These strata are composed of shale, tuff, silty mudstone and minor fine sandstone stacked in a laminated pattern, and the reservoirs are dominated by centimeter-thick tuff and silty mudstone. Since the stratigraphic thickness is below the λ/4 resolution limit and the geophysical property contrast between the reservoirs and surrounding rocks is faint, the seismic reflection signals of the reservoirs are submerged in the strong shale reflections without independent seismic responses, rendering them unpredictable by conventional seismic inversion methods. To tackle this issue, the concept of seismic geobody identifiability is proposed, referring to the quantifiable degree to which a geobody modifies the waveform of the seismic reflection event enclosing it when the geobody exists. Its value is correlated with the geophysical property contrast between the geobody and surrounding rocks, geobody scale and structure, as well as seismic data quality. This concept breaks through the λ/4 resolution restriction, providing a theoretical support for identifying smaller-scale geobodies. On the basis of the "upward convex" feature of the shale reflection event and the widening of the underlying seismic trough, a correlation model between trough widening magnitude and reservoir thickness is constructed, which successfully predicts shale oil reservoirs thicker than 4 m. Verified by 145 calibration wells, the prediction accuracy reaches 85.5%. This method enables accurate prediction of reservoirs with no independent seismic responses hidden in strong seismic reflections, providing a new idea for the exploration of unconventional oil and gas reservoirs.