| Comparing with the conventional partially hydrolyzed polyacrylamide, hydrophobic association water-soluble polymer (HAWSP) can exhibit better performance and special rheology, resulting in having been widely used in enhanced oil recovery. But for those particular complex reservoirs, single HAWSP still can't meet thickening efficiency, high salinity, high temperature, shear-resistant property. In view of this, people began to explore the research ideas that mixed the different polymers to improve their performance, many studies have shown that, the performance of mixtures could be greatly improved compared with single polymer, and was able to meet the application requirements. However, when the two oppositely charged HAWSPs were blended to form a mixture, what changes would occur to solution properties? which structural parameter would be the dominant factor? To understand these problems, this paper carried out the following studies:1. On the one hand, in the presence of acrylamide (AM), with the addition of n-amyl alcohol (PA), we obtained the change curve of the micellar aggregation number (Nagg) and block length (NH) of cetyl dimethyl ammonium chloride(C16DMAAC) by steady-state fluorescence quenching method, then on this basis, synthesized PNs(AM/C16DMAAC) with different block length; On the other hand, AM and 2-acrylamide fourteen alkyl sulfonate (NaAMC14S) were used as comonomer, pure water and ethanol/water(mass ratio of 1:3) were separately used as solvent, adjusted the dose of photoinitiator, the PMs(AM/NaAMC14S) with different molecular weight were synthesized by photopolymerization; By summarizing all kinds of characterization results, it was confirmed that NH and molecular weight respectively were the main difference of the PNs and the PMs.2. The curve of the PNs' viscosity-concentration was obtained by rheological measurements, the results showed that the block length increased, the degree of intermolecular association was more obvious, and resulted in higher viscosity of the polymer; the viscosity and I3/I1 value of the mixture by mixing the PNs and the PM-h increased with the longer NH and the higher concentration, PN-15/PM-h> PN-7/PM-h> PN-4/PM-h;3. To study the effect of molecular weight on the solution properties of the complexes, PN-15 and the PMs were blended to form a mixture, the viscosity and I3/I1 value of the mixture PN-15/PM-t mainly resulted from PN-15, and were always less than PN-15; when fixing the concentration of PN-15, and then graduatly added the PMs, with the concentration of PMs increased, the viscosity and I3/I1 of the PN-15/PM-t after blending were increased.4. Polymer HPN-15 and HPM-h?HPM-t with different degree of hydrolysis were respectively blended to form composite systems, for the HPN-15/HPM-h system, with the degree of hydrolysis became stronger, the degree of the interaction between the polymer component became weaker, and the growth of viscosity of the system was smaller; for the HPN-15/HPM-t, regardless of the degree of hydrolysis, similar to the unhydrolyzed system, the viscosity and I3/I1 value of the complexes HPN-15/HPM-t mainly resulted from HPN-15.5. By summarizing the influence of above three factors on the solution performance of the mixture, the following conclusions were obtained:increased the block length of one component in the mixture, the thickening performance of the mixture would be improved; the molecular weight of the two components was in the same order of magnitude, the viscosity of the complexes increased dramatically after mixed, and it would be decreased with the increasing degree of hydrolysis; Conversely, if there was a magnitude difference in the molecular weight between two polymers, regardless of the hydrolysis, the viscosity was mainly resulted from the component with higher molecular weight. These conclusions could lay a solid foundation and provide a favorable reference for improving the application performance of the complex system by adjusting the structure parameters of polymer. |
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