Abstract: Two point probability function and linear path function depicting the characteristics of core’s pore space are introduced. A new method of constructing digital core named stochastic search algorithm based on majority operator is presented. Its theory of constructing digital core and the stochastic search strategy for both pore voxel and grain voxel based on majority operator are illustrated in detail. Good intervals for majority operators when searching pore voxel and grain voxel are suggested to be [9,12], [4,7] respectively. Study shows that this method, without being constrained to lithology, can construct digital core with good quality. The constructed digital core’s pore space gains good topology and distribution which is similar to the genuine rock pore. Although a number of isolated pore and rock phase units appear in the core, their total fraction is quite small. The core’s pore space connection, isotropy and permeability are all good enough to make it a good tool for study of fluid distribution and flow in porous media. As the core’s connectivity becomes poor with its porosity decreasing, the method presented here can be better used for constructing digital core with large porosity.

Key words: digital core, stochastic search, majority operator, lattice Boltzmann method