FIELD: oil and gas industry.
SUBSTANCE: invention relates to the field of petroleum geology and can be used for the oil-saturated rocks wettability determining. Rocks wettability determining method by the core X-ray tomography method includes the standard cylindrical samples from the rocks core manufacturing, their extraction from oil and drying until the mass stabilization, followed by the obtained dry samples tomography with the 2D slices production, dry samples saturation with the sodium iodide solution and the saturated core samples repeated tomography performance with the 2D slices production, then, using obtained by the tomography 2D slices, performing samples 3D-reconstruction by the said 3D-reconstructions comparison for dry and saturated samples, at that, determining the said samples pore volumes, and the rock wettability determining using the samples established pore volumes, as the sodium iodide solution for the dry samples saturating a solution with the concentration of 300 g/l is used, and the saturation is carried out under vacuum for at least 3 hours, at that, during the samples 3D-reconstruction performance, determining the pore volume of not the whole sample, but only for the sample core at a distance of 3–5 mm from the sample upper and lower ends and 5–6 mm from the sample lateral sides using their pore volumes determined during the samples 3D-reconstruction performance, then calculating the K impregnation index of impregnation – as the ratio of the difference in pore volume between the dry V1 and the saturated sample V2 to the pore volume in the dry sample V1 according to the following formula: 
and by the impregnation index of the K impregnation obtained value judging on the core wettability by its hydrophilicity or hydrophobicity category determining.
EFFECT: increase in the rocks wettability determining accuracy.
3 cl, 4 dwg, 1 tbl
