Research On Flow Characteristics Of Low-permeability Sandstone And Throat

The low-permeability reservoir pore throat is subtle and sensitive.If the water injection rate is too low,the driving pressure will be insufficient,and the injection water will have a smaller spread,resulting in a low recovery factor.However,if the injection rate is too high,it will easily cause speed-sensitive effects and damage.The internal structure of the oil reservoir pores blocks the formed water flow channels and reduces oil recovery.In order to solve this problem,this paper takes the low-permeability sandstone core of Jilin Oilfield as the research object,and carries out CT scans and image processing operations on the core,and builds a two-dimensional pore structure model of the core on the basis of retaining the core pore structure.Based on the two-dimensional pore structure model,the computational fluid dynamics software Fluent was used to numerically simulate the oil-water flow process in the pore model,and the phase distribution and displacement effects of oil and water in pores of low-permeability sandstones under different water injection rates were analyzed.The results show that there is a best critical value for the water injection rate,so that when the oil-water distribution in the pores reaches a steady state,the volume fraction of crude oil reaches a minimum value;under the same water injection rate,with the increase of wettability,the distribution of oil and water is stable,and the pores The inner crude oil volume fraction is greater;when the distribution of oil and water within the pores is stable,changing the water injection rate and continuing the water injection can play a certain role in displacement.The research results lay a theoretical foundation for improving the recovery rate of low-permeability oil fields at the micro level.