To reconstruct the paleogeographic environment of productive horizons B12 in wells of Gurarinsko-Sobolin Oil Field (Tomsk Region), texture-structure rock characteristics, reflecting their sedimentation environment were determined. According to the quantitative granulometric-mineralogical analysis data of thin sections, the following steps were conducted: paleodynamic reconstruction, investigation of debris and cement mineralogical composition and determination of post-sedimentation alterations of terrigenous rocks. It was established that the sediments of layers B12 1 and B12 2 were formed in the coastal environment along offshore bars, barrier islands and rip current gullies.
lower Cretaceous
terrigenous rocks
sedimentation environment
granulometric-mineralogical analysis
post-sedimentation alterations
