Flow Simulation And Experimental Research Based On Microscopic Capillary Model

At present,the law of two-phase seepage is one of the most important scientific problems in the process of oil and gas field development.However,most of the researches are focused on the macroscopic seepage law,and this amplification method cannot capture the tiny fluid flow information.At the same time,most of the oil field development in China has entered the period of high water cut and extra high water cut.This paper aims to use kinds of methods to capture micro-flow information and explore the micro flow law.In this paper,the local wetting phase field model was used to study the influence of channel length,channel width,displacement pressure and other factors on the flow pattern of a single oil droplet isolated in the channel.Meanwhile,the influence of viscosity and capillary force on the flow pattern of oil droplet when it passes through the narrow channel is analyzed.Then,a unified model based on lattice Boltzmann method was used to establish the two-channel model to study the influence of two-channel width ratio on flow morphology.What's more,the random fracture generation method was used to establish multiple groups of different fracture density models,and the influence of matrix permeability,fracture density,number of holes and other factors on the oil-water two-phase flow were studied.Finally,the microcosmic experiments of single tube flow and glass etching were carried out to verify and compare the flow rules of oil and water in the single-channel and two-channel models.Simulation of local wetting phase field model shows that under the set model parameters,when the channel width is less than the diameter of oil droplets,the best pressure for the flow is about 500 Pa,under which pressure the time for oil droplets to pass through the channel is the shortest.The two-channel model was used to study the influence of different pore locations on two-phase flow.It was found that when the pore was connected with multiple channels,the overall flow velocity would be slowed down.Using lattice Boltzmann method and two-channel model,it is found that with the increase of channel width ratio and Ca number,the flow "range" of slug flow and bubbly flow becomes smaller and smaller.Random fracture network model study found that the main role of the pore is to connect the fracture and storage fluid,when the fracture can connect the hole through the model,the permeability of the whole model has a greater increase.The experimental results show that the probability of bubble flow and slug flow increases with the increase of single channel width.With the increase of oil phase viscosity,the oil phase is blocked in the small throat,and the finger penetration of water is more serious,and the displacement efficiency will be reduced.Flow tends to reduce conformance with the presence of "dominant channels",resulting in lower oil recovery.In this paper,the microscopic water drive oil seepage law in porous media is obtained,which provides a basic understanding for the high water-cut oilfield to improve the recovery efficiency greatly.