While water exists in the waxy crude oil, gelling process of this non⁃Newtonian oil⁃water two⁃phase system not only has the properties of waxy crude oil but also its own specific characteristic as decrease of temperature. Both the gelling temperature limit and change rule of gelling strength in W/O waxy crude oil emulsion system under different emulsified water fractions, were investigated by rheological measurement. The results indicate that the characteristic gelling temperature and the strength of the gels increase with the increasing of emulsified water fraction, when the temperature decreasing at a certain rate; the gelling temperature in W/O waxy crude oil emulsion system of any given emulsified water fraction rises with the increasing of cooling rate, while the gelling strength decreased with the cooling rate rising under the constant pressure. The research results of the effect of emulsified water on the gelling characteristic for waxy crude oil at cooling process provides necessary support for the development and application of flow technology for multiphase transportation.

Surfactant/Polymer (SP) combination flooding is an effective method to enhance oil recovery of high quality reserves,while its surface produced liquid treatment technology and the simplification and optimization of operating parameters are both still a challenge for the promotion of the chemical flooding technology industrialization.In this paper,the emulsification of SP combination flooding produced liquid is characterized by multi⁃factor perpendicular experiments,and then the effect factors of demulsification and dehydration are studied.Significant test results indicated that,compared with the temperature and water cut,the effect of the concentration of surfactant and polymer in the produced liquid on dispersivity and electronegativity of the bulk was lower,which showed the greater contribution to emulsification stability of produced liquid,thus the demulsification of the produced liquid was declined.Bottle test experiments indicated that a single mechanism of improving demulsification temperature or prolonging demulsification time couldn’t fundamentally improve the dehydration rate of the produced liquid and reduce the oil content in the water after separation,meanwhile,the improvement of the pH of the water phase and the strong shear effect of the flow field would further deteriorate the effect of demulsification,dehydration and the water quality after separation.