Study On The Mechanism Of Reduced Oxygen Air Huff-puff In Deep Heavy Oil Reservoirs

Lukeqin Reservoir is a typical deep heavy oil reservoir with poor physical properties,severe heterogeneity,rapid water cut rise,and poor development effect.It is planned to use oxygen-reduced air stimulation to improve recovery.Therefore,on the basis of domestic and foreign literature research and block profile analysis,this paper obtains oil,gas and water in the process of water flooding,gas injection and continuous production through the use of one-dimensional sand-filling tube experiment,two-dimensional visualization experiment and numerical simulation research.Distribution and migration characteristics,clearly describe the mechanism of water and oil suppression of oxygen-reduced air throughput,and finally analyze the influence of geological conditions and process parameters on the throughput effect,and apply the research results to the site.The main results and understanding of the paper can be roughly divided into the following aspects:(1)More than 70% of the oxygen-reduced air enters the high-permeability layer,the bubbles of the dispersed phase expand and merge during production,and the Jia Min effect occurs when passing through the pore throat.The seepage resistance of the aqueous phase in the high-permeability layer increases and turns to the low-permeability layer.Therefore,the use of a low-permeability layer to block the high-permeability layer is the main effect of oxygen-reduced air throughput;however,the air bubbles are not stable,and the blocking effect will fail after a period of time.(2)The key geological parameters of oxygen-reduced air throughput are permeability difference,crude oil viscosity,formation depth,and reservoir thickness,and the process parameters that have the greatest impact are the production rate,gas injection volume,and gas injection speed;Oil wells with shallow and deep burial depths,high crude oil viscosity,large thickness and high water content can better exert the effect of oxygen-reduced air throughput;only from the perspective of increasing oil production,the process parameters should be set to high gas injection rate and high injection Gas volume and high distribution output.The research results can provide a certain theoretical basis and technical guidance for the application of oxygen-reduced air in Lukeqin heavy oil reservoir.