The Study On Gas-Water Two Phase Percolation Characteristics Simulation In Porous Media

Saline aquifer sequestration is considered to be one of the main ways to achieve deep carbon reductions. Many reservoirs macroscopic properties, such as permeability, capillary force, relative permeability, etc., which are dependent on the microstructure and composition of the solid and its physical properties of the fluid in the pore space, i.e. microstructure and physical properties are fundamental, macroscopic properties and the phenomenon are the appearance. Method of macroscopic properties of reservoir numerical simulation, which further analysis saline aquifers CO2storage capacity and safety assessment has important significance.Since the microscopic pore structure of reservoir core is very complex and irregular, traditional capillary bundle model can not accurately describe the absolute permeability of reservoir cores. In this paper, using the advantages of the pore network model can truly reflect the microscopic pore structure of reservoir core and capillary bundle model does not rely on fluid properties, avoiding the disadvantages of both models get an improved calculation method of capillary bundle models. Using this algorithm calculated absolute permeability for four kinds of BZ series sand packed compared with the experimental values, the error and can be controlled at around6%. This is compared with the traditional model of capillary bundles and pore network flow model has greatly improved.In order to allow seepage simulation conditions match the experimental conditions. In this paper, both autonomously designed a high-pressure, temperature measurement system device can simultaneously interfacial tension and contact angle. The device can be applied to the hanging drop method to measure interfacial tension and sitting drop method to measure contact angle. With this set of measured system devices:CO2at a supercritical pressure given temperature below the critical temperature prospective, CO2and NaCl solution interfacial tension will become smooth and stable; Tapered calculation method is more suitable for the contact angle.The experimental parameters were used as input parameters for gas-water two-phase flow modeling based on pore network model, simulation Drainage and Imbibition process can get the corresponding gas-water two-phase relative permeability curves and capillary force curve. The effects of filling sand particle size, temperature, pressure, NaCl concentration of gas-water twophase flow characteristics are investigated. From the simulation results obtained:In Imbibition process, residual saturation of CO2are greatly influenced by injection pressure and the concentration of NaCl, with the injection pressure from3MPa to8MPa, the residual CO2saturation from25%to10%, NaCl solution concentration from0.102mol/L to1.0mol/L, the residual CO2saturation rose from10%to20%.