| In view of the situation of extra large or fractured pore and fractured vuggy reservoir in old oilfield,the water injection development efficiency is seriously affected,and then the oil recovery of the reservoir is affected.In this paper,a stable water-based thermosetting phenolic resin emulsion system was constructed by phase inversion emulsification.The emulsion was cured at high temperature by using emulsion modification and phenolic resin curing characteristics,and the factors affecting the curing properties of the emulsion were studied.Then the basic properties and water plugging performance of the emulsion system were evaluated.First,the emulsifier and inorganic salt were screened by phase inversion emulsification.The best emulsifier for emulsified thermosetting phenolic resin was obtained: sodium caseinate,emulsified thermosetting phenolic resin,the most suitable inorganic salt solution:anhydrous sodium sulfite aqueous solution,the emulsion formed had good apparent fluidity and stability.Secondly,through single factor experiment,5 factors affecting the stability of emulsion system(oil / water ratio,mechanical agitation speed,emulsifier dosage,brine concentration and dripping acceleration)were analyzed.Factors affecting the stability of emulsion system were optimized by orthogonal experiment,and the variables of various experimental conditions were adjusted.4 factors affecting the curing properties of emulsion system(oil / water ratio,mechanical agitation speed,emulsifier dosage and brine concentration)were analyzed.Finally,the best experimental conditions were obtained: the ratio of oil to water was 1?4,the stirring speed was 800r/min,the amount of emulsifier was0.8%,the concentration of brine was 1000mg/L(the reaction temperature was 50?).Under this condition,a water-based thermosetting phenolic resin emulsion with good stability,curing property and temperature resistance and salt tolerance was prepared.The particle size,viscosity change,temperature and salt tolerance of the emulsion were investigated.The results showed that the particle size of the optimized formula emulsion was mainly distributed in10?15?m,the emulsion can be well injected into cracks.At room temperature,the emulsion viscosity is about 5.5±0.5MPa?s,the viscosity increases obviously at 70?;The hardness of the cured emulsion formed by the optimized formula emulsion did not change significantly under the condition of continuous high temperature and high salinity,indicating that the cured product had better temperature resistance and salt tolerance.The plugging performance of phenolic resin emulsion prepared by water plugging evaluation experiment was investigated.The results showed that the emulsion system had good sealing effect and erosion resistance. |
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