Research On Microscopic Seepage Simulation Based On Digital Core

Lattice Boltzmann method is called mesoscopic simulation method.It is an important scientific research method because of its excellent parallelism,simplicity of boundary conditions,and easy implementation of programs.Digital core technology can accurately extract rock pore space at the micro and nano scale,and is widely used in multiphysics simulation.In this study,the lattice Boltzmann method was used to study the microscopic seepage mechanism of fluid based on sandstone digital cores.In this study,through filtering,edge detection,threshold segmentation and image binarization of the core image,the sandstone image was 3D reconstructed,and the 3D pore space was extracted.The REV analysis method was used to extract the pore space of five REV sub-samples and Statistics on its pore structure are carried out.By establishing a lattice Boltzmann calculation model suitable for the seepage simulation of rock pore media and verifying the accuracy of the model,then the five REVs were simulated with different pressure differences to obtain the pressure field,velocity field,flow velocity,flow rate And the simulation result data such as saturation,combined with the pore data such as porosity,porosity and permeability of the REV surface,the relationship between the seepage characteristics of different REVs under the same pressure difference and the pore structure of REV,and the seepage law of REV under different pressure differences were analyzed.The influence of fluid viscosity on seepage was studied.Finally,the starting pressure gradient of each REV was obtained by the differential pressure-flow method,and the influencing factors of the starting pressure gradient were analyzed.By establishing a three-dimensional digital core model,this study further studies the seepage mechanism at the microscopic scale,accurately describes the fluid seepage law in the rock,breaks through the limitations of conventional macroscopic experiments,and provides a reference for the study of the seepage mechanism of porous media and petrophysics and other fields.