Method for estimating fluid saturation of a rock

A method for estimating fluid saturation of a hydrocarbon-bearing rock from a rock image, comprising:

• obtaining a 3D image of a rock from the hydrocarbon-bearing formation in a field, wherein the 3D image is comprised of a plurality of voxels and the 3D image has a resolution;
• processing the 3D image to segment the 3D image by selecting each voxel of the 3D image to represent either a pore space in the rock or solid material in the rock;
• estimating an image pore volume of the rock from the segmented 3D image, the image pore volume lacking a sub-resolution pore volume of the rock;
• determining a corrected pore volume adapted to account for the sub-resolution pore volume of the rock;
• estimating an image-derived wetting fluid saturation of the rock using a direct flow simulation on the 3D image;
• and
• determining a corrected wetting fluid saturation of the rock from the image-derived wetting fluid saturation, the image pore volume and the corrected pore volume of the rock.