Study On Composite High Temperature Sealing System For Heavy Oil Thermal Recovery

During steam stimulation,high permeability zones will change into strong gas suction one sand the amount of gas in take in low permeability zones will belittle and even one,under the influence of the mal development of barriers,permeability contrast between layers and steam overriding and so on.With the increase of steam stimulation rounds,the effect of steam stimulation will decline because of the further influence of the phenomenon of gas break through hand well interference.Aimed at the increasingly serious steam problems,this paper has developed a composite plugging system using natural materials.In this paper,fly ash is used as the inorganic particle compound with tannin gel system,and the mechanical technology is used as the theoretical support to carry out the experiment of pre-activation treatment of fly ash.The active phenolic cross-linking agent has the advantages of low free aldehyde content and high hydroxyl methyl content,which has sufficient reactivity and does not cause harm to the environment.Through static evaluation tests in the laboratory,salinity,temperature etc.On the new type composite plugging agent is studied.Then the rules of the system flows in the porous media are studied.The experimental results show that the system has no influence on the strength of the gel in the environment where the salinity is less than 12,000ppm;in the temperature range of 70~110?,the temperature has little effect on the system;the system is kept at a constant temperature of 90?,and the dehydration rate is maintained.,the system was placed at 90 for 30 days,the dehydration rate was maintained at ?14%,showing good temperature resistance and aging resistance;the system can achieve a core plugging rate of more than 95% for different permeability and shows excellent erosion resistance.