Study On The Interaction Of Hydrophobic Associated Polymer With Yin, Nonionic Surfactant And Anionic / Nonionic Composite Surfactant

Hydrophobically associating polymer solution has properties of good resistance to temperature, salt and shear thinning, beeause of its unique molecular structure.It gradually showing broad application prospects in enhanced oil reeovery. In recent years, the interaction between hydrophobically associating polymer and surfactants has been the hot point of the research working in the world. Handing the relationship between the macro-regularities of their interaction and solution microstructure has vital practical significance in guiding the application of hydrophobically associating polymer/surfactant flooding system.This thesis systematically studied the interaction between different types of surfactants and the hydrophobic associating polymer with different levels of hydrophobe content (DP-1、 DP-2、DP-3), through the rheological testing means:steady stress sweep and creep-reply. The surfactants include anionic surfactant (sodium dodecyl benzene sulfonate,SDBS), nonionic surfactant (lauric diethanolamide, CDEA-12) and anionic/nonionic combined surfactant. Through the above research, both the variation rule of system’s macroscopic viscosity & microstructure and the association density & strength of molecular structure was gained. It is noted that the change of system’s macroscopic viscosity is caused by the latter. Experimental results show as follows:1) The higher concentration and hydrophobic groups content of the polymers (DP-n). the more stronger interaction with surfactants. The extreme zero shear viscosity (η0 max) of DP-n/SDBS increased rapidly when hydrophobic groups concentration (CH) increases. On the macro, the zero shear viscosity was exhibited, first increasing and then decreasing. In the micro.the associating structure number of the surfactant/polymer binary systems (Go) and the strength of the association (TR) increased first and then decreased, with increasing the concentration of SDBS. TR reduction magnitude is larger than Go’s, the viscosity is mainly affected by the structural strength of the association in the process of viscosity reducing.2) The interaction of DP Series polymer and CDEA-12 increases gradually with the increase of hydrophobic group content. The polymer concentration palys an important role in DP-n/CDEA-12 systems, the results show:in the low polymer concentration range (2000 mg /L), with increasing CDEA-12 concentration, η0 first increased and then unchanged. In the micro. Go slowly increased and TR increased sharply until a plateau. The main change in the zero shear viscosity is controlled by the structural strength of the association. At the high polymer concentration range (4000 mg/L), with increasing CDEA-12 concentrations TR rapidly increased and was up to the maximum at 0.5 mmol/L of CDEA-12. The no decline interval appeared with Go first increasing and decreasing later, which was affected mainly by Go and the amount of CDEA-12 at η0max reduced.3) The compound of surfactant composition have a significant impact on the interaction between polymer and surfactant:When the concentration of SDBS is in the rising stage of the system viscosity of polymer/SDBS, the η0 of system is increase with the increase of the concentration of CDEA-12, Go and TR thereupon rising too. This shows the zero shear viscosity increases by the increase of the number of intermolecular association structure and the structural strength of the association. When the concentration of SDBS is Cs max in the polymer/SDBS system,a small amount of CDEA-12 can damage the association structures, the number of intermolecular association structure and structural strength of the association rapidly reduced, η0 reaches a minimum. With the increasing of CDEA-12, the mixed surfactants dominated by CDEA-12, the Go and TR increases gradually; When the SDBS concentration was in viscosity reduction stage, with the increasing concentration of CDEA-12,η0, Go, TR of DP-n/SDBS were first decreased and then increased. When the concentration of CDEA-12 is certain, with the change of SDBS’s concentration, η0, Go, TR showed that increased at first and decreased then. The amplitude of variation of the DP-n/ combined surfactant system is smaller than the DP-n/SDBS system.This thesis stresses on the interaction rule between the hydrophobic associating polymer and single surfactants & compound surfactant through the variation rule of system’s macroscopic viscosity and the impact of system’s micro-associative structure. This thesis aims to provide some theoretical guidance and reference for both the select of hydrophobic associating polymer & surfactant of SP flooding and the complex of various surfactants.