Screening Study on Rheological Behavior and Phase Transition Point of Polymer-containing Fluids produced under the Oil Freezing Point Temperature

For an increasing implementation of the low-temperature transportation in oilfield, it is urgent priority initially to study the physical and chemical properties to provide the vital technical support for the low-temperature transport of the polymer flooding. In this paper, the rheological behavior of polymer-containing fluid produced from the Daqing polymer flood were first studied for an adaptation of transportation under the oil’s freezing point temperature. The experiments progressed with different temperature, shear rate, water content and polymer concentration which have great impacts on the viscosity of the fluids produced aiming to find the phase transportation point for the application of the low-temperature transportation. It was displayed that a significant discontinuity in the viscosity occurs at some range of water content. Before the phase transition point, presented in W/O (water-in-oil) emulsion, the viscosity was lifted with the increase of the water content while after the phase transition point, forming the O/W (oil-in-water) type emulsion, the viscosity was dropped with an increase of water content. The phase transition points strongly depend on the polymer concentration in the fluids Produced. It was demonstrated that the phase transition points of polymer-containing fluids were 65%, 70%, 50%, 50% and 50%, corresponding to the polymer concentrations of 315mg/L, 503mg/L, 708mg/L, 920mg/L and 1053mg/L, respectively. The characteristics are attributed to the viscous polymer. The fluidity of the fluid produced was decreased with the increase of polymer concentration.