Clinoform-type deposits of lateral scope progradation are characterized by a complicated structure. The mailing of sandbodies, which control hydrocarbon pools, is a great problem even when the area has been thoroughly surveyed by seismic and drilling. The problems of sandbody prediction on seismic data are inconclusive because these bodies are not adequately reflected in seismic. As examples, in this report, some attempts to establish the mechanism of the formation of clinoform sandbodies have been made in the Neocomian deposits in the wellsurveyed Priobskoye and Prirazlomnoe fieIds of Western Siberia. This should be known in order to substantiate parameters for mapping of promising areas on seismic data.