| The mean molecular weight of mixture anionic surfactant is determined by using combination method of high pressure liquid chromatography (HPLC) and electrospray ionization mass spectra (ESI-MS), then the composition and molecular structure can be characterized by combining analysis of 1H-NMR spectrum and element. According to above results,there are di or poly-polar group exist in the molecule structure of the surfactant, especially for those which have more aromatic ring; The interfacial activity of the composition that has the more branched chain of alkyl group and the shorter molecular chain of branched chain is lower. However, it has outstanding dissolubility in water, therefore, it have excellent solubilization effect to the composition with mono-polar group; The active composition of macromolecule structure have more average number of methyl group, which will increase the coverage rate of hydrophobic group on oil aqueous interface, line hydrocarbon chain along closely, as well as the temperature tolerance is better than other composition, so which are the main composition on reducing interfacial tension as additive agents for thermal recovery; However, the main defect of these composition is low dissolubility in water, so the ultra-low interfacial tension can not be obtained when it used lonely. Therefore, the synergetic effect is very important to mixture flooding system, and the ultra-low interfacial tension can be obtained by means of complementation of molecule structure, improvement of the hydrophilic-lipophilic balance and increase the allocation of macromolecule on oil aqueous interface. However, the synergetic effect is sensitive to the composition balance, which will diminish or disappear for imbalance adsorption loss on rock and the difference of fluid flow ability through porous medium. Fortunately, the adsorption and precipitation loss of the mixture flooding system can decrease by means of adding small-molecule non-cloud point non-ionic surfactant, which have favorable water solubility and the chelation ability with multivalent cations, competitive adsorption with other composition, as a result, the adsorption site on surface of reservoir sand dramatically decrease, so the composition balance of flooding system can keep well, then enhanced oil recovery.Furthermore, the significant factor for low oil displacement efficiency in the formation of low permeability and high residual oil saturation is low sweep efficiency, which determined by seriously heterogeneity of heavy oil reservoir and the unfavorable mobility ratio between oil displacement system and heavy oil. The base solution of the new system used for profile control and blocking off is liquid with low viscosity liquid, so the aim of plugging off in mid-depth formation can be achieved; Latent curing agent used in the system is a kind of chemiacal agent which has steady chemical nature at reservoir temperature, however, it would be decomposed at higher temperature after steam injection, therefore, the condensation polymerization and densification of the system would be promoted, as a result, the temperature selectively blocking off can be achieved. At the same time, it strongly bonded with the surface of rock by hydrogen bond. At last, the swelling resin formed, in which hardened plastic is continual phase and gas is dispersion phase, so the efficiency of formation sealing to high capacity channel is higher.As is shown according to simulated experiment of steam flooding with multi-barrel, the recovery ratio has been enhanced 23.4% for the low permeability and high residual oil saturation formation with combination system of oil displacement and profile control.
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