Direct numerical simulation of petrophysical properties of rocks with two or more immicible phases

A system for analyzing a rock sample, comprising:

• an imaging device configured to produce a digital image volume representative of the rock sample;
• and
• a computing device coupled to the imaging device and comprising:
• one or more processors;
• and
• one or more storage devices, coupled to the one or more processors, and configured to store instructions that, when executed by the one or more processors, configure the one or more processors to:
• segment a digital image volume corresponding to one or more images of the rock sample, to associate voxels in the digital image volume with pore space or solid material;
• for each pore space voxel:
• apply a distance transform to the pore space voxel, wherein the distance transform assigns a distance value to the pore space voxel specifying distance from the pore space voxel to a solid material voxel;
• perform a direct numerical simulation of drainage of the rock sample, and as part of the simulation to:
• for a pore space:
• select each distance value, assigned to a pore space voxel, that is greater than a predetermined threshold value to represent a radius of a sphere of a non-wetting fluid introduced into the pore space, and wherein the sphere is centered at the pore space voxel corresponding to the distance value;
• and
• numerically analyze the digital image volume to characterize a material property of the rock sample at a non-wetting fluid saturation produced by the drainage.

A non-transitory computer readable medium encoded with instructions that when executed cause one or more processors to:

• segment a digital image volume corresponding to one or more images of the rock sample, to associate voxels in the digital image volume with pore space or solid material;
• for each pore space voxel:
• apply a distance transform to the pore space voxel, wherein the distance transform assigns a distance value to the pore space voxel specifying distance from the pore space voxel to a solid material voxel;
• perform a direct numerical simulation of drainage of the rock sample, and as part of the simulation to:
• for a pore space:
• select each distance value, assigned to a pore space voxel, that is greater than a predetermined threshold value to represent a radius of a sphere of a non-wetting fluid introduced into the pore space, and wherein the sphere is centered at the pore space voxel corresponding to the distance value;
• and
• numerically analyze the digital image volume to characterize a material property of the rock sample at a non-wetting fluid saturation produced by the drainage.