Study On The Preparation And Properties Of Polymer Microspheres Profile Control Agent

At present, most oilfields have stepped into high-aquifer stage in our country. Because ofreservoir heterogeneity, the injected water along the high permeability layer and waterproduction rate is rising year by year. Only through deep adjustable plugging, can effectivelyimprove the reservoir heterogeneity, improve the injection liquid volume sweep efficiency,and ultimately improve the oil recovery of water flooding stage. Polymer microspheres is anew deep profile control technology, in order to solve the contradictions problem in recentyears. It depends on the expansion of the nano and micron meter grade polymer microspheresunder water to plugging formation pore throat of step by step to achieve deep profile control,has the advantages of low viscosity, online injection and so on. In order to solve the problemof well water, should be pay attention to well water trend, using a variety of measures todetermine the water layer, adopt the corresponding technology for the water plugging.In this paper, By dispersion polymerization technology using acrylamide (AM), methylacryloyloxyethy trimethyl ammonium chloride (three DMC) and2-acrylamide-2-methylpropane sulfonic acid (AMPS) as main monomers, ammonium sulfate as the phase dispersant,with polypropylene acyl oxygen ethyl trimethyl ammonium chloride (PDAC) and poly2-acrylamide-2-methyl propane sulfonic acid (PAMPS) as dispersion stabilizer, usingammonium persulfate as initiator, to prepare cationic polyacrylamide (CPAM) and anionicpolyacrylamide (APAM). Effects of several factors were studied on dispersion polymerization,such as monomer ratio, ammonium sulfate concentration, stabilizer concentration, pH valueand temperature. The structure of the polymer was characterized by FTIR; the particle sizeand distribution of polymer products are determined by optical microscopy and dynamic lightscattering analyzer; capillary viscometer is used to test the characteristics of the polymerviscosity number; core displacement experiment is used to test the different concentrationpolymer microspheres with different salinities and different permeability of the core pluggingeffect.Experiments results show that the optimum conditions of the synthesis of cationicacrylamide polymer (CPAM) is: the concentration of monomer is15%, the concentration of ammonium sulfate is30%, the dosage of stabilizer is0.5g·g (monomer)-1, the mole ratio ofAM/DMC is8/2, the reaction of the pH value is5-6, the temperature is50-55℃; theoptimum conditions of the synthesis of anionic acrylamide polymer (CPAM) is: theconcentration of monomer is15%, the concentration of ammonium sulfate is23%, the dosageof stabilizer is0.4g·g (monomer)-1, the mole ratio of AM/AMPS is8/2, the reaction of thepH value is6, the temperature is65℃.The experimental results show that the low permeability formation plugging effect ofCPAM microsphere emulsion with1%solid content on the1000mD is very good, theplugging efficiency above90%, but the polymer emulsion has poor salt resistance, the stratumplugging effect of salinity is only about30%; APAM emulsion with1%solid content havegood blocking effect for low permeability formation, plugging efficiency can reach above80%, the effect of plugging high permeability formation is not obvious, polymer microsphereof APAM has good salt resistance, for the mineralization of the low permeability rock, theplugging effect still remain more than70%.