Research On The Salt Resistant Polyacrylamide With Mid Molecular Weight

In recent years, the tertiary oil recovery requires specific performance with development of polymer flooding. Aiming at the relatively low permeability reservoir we need flooding polymer with low molecular weight and high viscosity of the sewage system. However, salt resistance of HPAM is relatively poor, in order to meet the injection requirement of low permeability reservoir, if we reducing the viscosity-average molecular weight, the viscosity of the system would have a significant decrease at the same time that can not meet the needs of the flowing control. In order to solve this problem, in recent years, domestic and foreign research institutions have done a lot of work in terms of salt resistance of polymer, and the salt resistant polymer which has a variety of different molecular structure compared with HPAM has arisen..Aiming at this problem, this paper analyzed the synthesis mechanism of MW salt resistant PAM, designed a new type of functional monomer: twelve-alkyl diallyl amine(DPA), the synthetic method of salt resistant PAM with mid-molecular weight, effects of initial temperature, SMR proportion, functional monomer concentration, initiator concentration and the reaction time and other related parameters, and ultimately determine a system of the synthesis process of molecular weight of salt resistant PAM. Synthetic conditions of salt resisting PAM molecular weight were DPA dosage :0.2%,SMR :13.3, reaction time: 4h, reaction temperature of 30℃, the alkaline conditions and the concentration of initiator is 15mg/L. Polymer products with a good anti salt performance of middle molecular weight were synthesized.We have studied on the retention interaction of mid-MW salt resistant PAM and performance rate of oil-water emulsification, reversible viscosity retention rate, surface active agent, the results are as follows:(1) we found that the mid-MW of synthesized polymer retention capacity was higher than that of conventional polymers, the time to achieve balance and retention is longer, indicating that the mid-MW polymer is better than that of common salt resistant polymer.(2) mid-MW salt-resistant PAM could increased the viscosity of the solution with surfactant concentration, when surfactant concentration reached 1.0mmol/L, we have the maximum viscosity; continue to improve the surfactant concentration, the viscosity of the solution decreased rapidly. The concentration of polymer in the extremely dilute region and semi dilute solution without winding and surface active agent area have the same trend, the addition of 1.5mmol/L surfactant at high shear rate, anti salt in polymer solution with the apparent viscosity and strong shear resistance than the pure polymer solution high table.(3) we mixed the crude oil and polymer solution which is after the emulsion stability test showed that the polymer has good emulsifying property. The results of this study will have a positive reference in the practical application of mid-MW salt-resistant polymer in oilfield.