Development and application of polymetric surfactant emulsification and viscosity reduction system

Compounding polymer AP-P4 with high viscosity-reducing Gemini Surfactant HD,which is used as an emulsifier viscosity reduce,to improve the stability of the O/W emulsion while the viscosity reduction rate is kept.A polymeric surfactant emulsification and viscosity reduction system capable of forming a relatively stable O/W emulsion of heavy oil(0.5%HD+0.1%AP-P4)is then compounded.The system has been characterized as a high viscosity reduction rate and high stability.Meanwhile,the production liquid does not need to be added with a demulsifier and only needs to be heated to 70°C to achieve effective demulsification.The influencing factors of the performance of the polymetric surfactant emulsification and viscosity reduction system were studied.When the oil-water ratio was 70:30 and 60:40,the viscosity reduction rate was 97.47%and 99.09%,respectively;after 15 h at 30°C,the dehydration rates were 95.8%and 99.2%,respectively.The dehydration rate after 15 h at 70°C was 98.1%and 99.4%,respectively;at 30∼50°C,the water phase temperature has a greater impact on the viscosity;at 60°C,70°C,the water phase temperature has little effect on the viscosity;as the temperature of the aqueous phase increased,the stability of the emulsion deteriorated.When the aqueous phase temperature was 30°C,50°C and 70°C,the dehydration rates of the emulsion after 15 h were 95.8%,96.7%and 98.1%,respectively;As the degree of mineralization increases,the viscosity reduction rate decreases,and the stability of the emulsion deteriorates.The system has been used in field test for 2 injection wells,and the production rate of the two wells increased with a peak value of 25 m3/d and 20 t/d,respectively.

Migration characteristics and profile control capabilities of preformed particle gel in porous media

Inspired by the viscoelastic displacement theory,a product called preformed particle gel(PPG)is developed as conformance control agent to enhance oil recovery and control excess water production.The migration law of PPG suspension in porous media is related to its deep profile control and displacement capability.Laboratory experiments indicate that PPG suspension has good viscosity increasing,and the apparent viscosity decreases with the increase of shear rate.PPG suspension is mainly elastic,and its network structure makes it have certain shear stability.PPG particles realize migration in porous media in the way of“accumulation and blockage/pressure increase/deformation and migration”.When the ratio of the PPG particle size to the pore throat diameter d ranges from 35.52 to 53.38,the particles can match through the porous medium.When the permeability difference of the parallel model is 5,PPG suspension has the highest profile improvement rate,69.10%.PPG suspension can adjust the planar heterogeneity,and increase the oil recovery rate by 20.75%.The PPG suspension can effectively start“cluster"、“film”and“blind end residual oil”,and has a high oil washing efficiency.The core NMR T2 spectrum shows that PPG suspension mainly reduces oil saturation in mesopores and macropores.After PPG flooding,the EOR capacity of small pores is the highest,39.11%.