Pore-throat Partitioning Of Porous Medial Based On LKC Medial Axis Extraction Algorithm

Pore-throat feature of the porous medium has a close relation to oil and gas reservoir.Research of porous medium feature is conducive to improving rate of oil and gas recovery and is of great theoretical significance and practical value to the analysis of the microscopic structure of core.Pore-throat partitioning of porous medial is the key step of pore network model constructing and pore-throat characteristic parameter analysis.This paper mainly focuses on the study of pore-throat segmentation algorithm and main works are as follows:Combined with the research progress on pore-throat partition,discuss relevant algorithms of medial extraction and pore-throat segmentation;Segment the CT images of core by a threshold method for digital core volume construction;Count num of rock and pore connected components and remove pore and rock island with the largest connected object remains;The medial axis preserving the topology of void space is constructed by LKC algorithm based on an Euler table and an octree data structure which is presented by lee;Based on the distance between the 26-neighbor of skeleton points,a new processing method for recognizing skeleton node is proposed;Computing node's inscribed sphere radius is used to remove noise branches;Set a threshold and remove branch paths which are less than the threshold;Present an algorithm for calculating mini-cross sectional surface's(MSS)area and direction and use MSS area as a basis of space size,normal vector as pore orientation.Locate parting plane with pore and throat's MSS area and then split pore and throat space.Experiment results show that: the node identification algorithm presented in this paper remove "fake node" to distinguish nodes from ordinary points accurately;MSS is suitable for representing porous medial space size;The pore throat partitioning algorithm which is based on mini-cross sectional area and LKC has good practicability for its relatively ideal axis,location of pore-throat parting plane and partitioning result,but still needs to reduce time cost.