Synthesis Of A Rigid Core-shell Structure Flooding Polymer

With the development of chemical flooding in enhanced oil recovery technology, promoting the use of reservoir conditions (temperature, salinity, etc.) is worsening, the modified linear polyacrylamide polymer can not meet the application needs. In recent years, nonlinear dendritic polymer has become a hot topic in the research of polymer flooding for oil displacement because of good temperature, salt and shear resistance. With ethylenediamine and other small molecules as the core of the dendrimer, it has low viscosity, poor salt resistance, compact structure, incomplete reaction and low purification efficiency, complicated products. Therefore, in this paper, we use diethyl 2,4-diacetyl-3-(4-bromophenyl) pentanedioate(DDP) as a rigid structure unit core. By ester exchange, Michael addition and amidation reaction, we designed and synthesized a rigid core-shell structure of macromolecules, and polymer for oil displacement with rigid core-shell structure was synthesized by free radical polymerization.The paper obtains the following results:(1)Theoretical calculation for the screening of compounds with rigid structure:Using Gauss software and MOP AC software to simulate and calculate the energy orbit, Gibbs free energy, reaction heat and organic hydrophobic constant of different rigid monomer, on the basis of the simulation calculation, the modified experiment of rigid monomer was carried out, and the yield was calculated, the rigid monomer diethyl 2,4-diacetyl-3-(4-bromophenyl) pentanedioate was screened out. The integrity of the structure was characterized by nuclear magnetic resonance spectroscopy (’HNMR) and carbon spectroscopy (13CNMR).(2)With diethyl 2,4-diacetyl-3-(4-bromophenyl) pentanedioate as a core, by ester exchange, Michael addition and amidation reaction synthesized a rigid core-shell structure of macromolecules (DDP2.0). Optimize conditions of the synthesis process, use the Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance hydrogen spectrum (’HNMR) and end group titration method to characterize the structure.The results show that the optimized synthesis process and the purification condition make the DDP2.0 molecular structure more complete.(3)The copolymerization of rigid core-shell structures of large molecular DDP2.0 and acrylamide (AM) and acrylic acid (AA) copolymer, will synthesize and optimize rigid core-shell structure of dendritic polymers (PDAAM), which has good characteristics of temperature, salt and shearing resistance. And the synthesis optimization process conditions of PDAAM are obtained:modified DDP2.0 monomer was 0.8%, Functional monomer was 0.7%, hydrolysis degree of polymer was 35%, the Initiator dosage was 0.25%, cosolvent urea dosage wass 2% of the monomer concentration, causing temperature 45℃.(4)Through infrared spectroscopy, nuclear magnetic resonance spectroscopy and scanning electron microscopy, we studied the microstructure of a concentration of 1750mg/L solution of PDAAM. The results showed that the polymer molecules formed a more regular and compact three-dimensional network structure in solution, which showed that the interaction between the molecular chains was stronger and the solution stability was better.(5)Application performance evaluation results show that the PDAAM solution has obvious shear thinning properties, and it has a certain elasticity; PDAAM has good salt resistance and shear resistance (when the Ca2+/Mg2+ ion concentration is 1500mg/L, the retention viscosity of 1750mg/L polymer solution after shearing is close to 60%), and the solubility needs to be promoted.