Investigation of the petrophysical properties of a porous sandstone sampleusing confocal scanning laser microscopy

Confocal scanning laser microscopy (CSLM) is used to produce images of the two- and three-dimensional distribution and geometry of pore space in a res ervoir sandstone and measure the 2D distribution of pore throat radii. Nond estructive serial sectioning of the rock using laser light at 100% illumina tion, combined with image thresholding and histogram equalization technique s allow the pore volume structure of the uppermost 100 mum of the sample to be reconstructed. Negative imaging of the pore volume gas e superior depth and feature resolution compared to positive (reflection) imaging. Artefact s encountered in applying classical Medial Axial Transforms to CSLM images include branch networks dominated by coordination numbers of 3. Skeletoniza tion using Euclidean distance maps gives increased accuracy in the descript ion of the pore network. Measured pore throat size distribution in the rock is strongly exponential and described by the expression y = 219(e)(-0.25x) where 3, is the number of pore throats.