Study On Shearing Stability Of HPAM Solution In Flooding

The degradation of HPAM is an important factor that influences the effect of polymer flooding. During the process of injection distribution, the total viscosity loss of the aqueous solution comes up to 50%-60%. Thus, it is very important to ascertain the laws and factors that influence the shear stability. This paper does some researches on the shear stability of HPAM in the injection process by indoor experiments, field practice and theoretical analysis. In the process of injection distribution, the pump is the most major equipment that influences the HPAM viscosity. The indoor experiments examine the influence caused by the mixing speed: when it is in the range of 0-400r/min, the HPAM solution shows shear thickening; when it is in the range of 500-800r/min, the HPAM solution shows shear thinning, when it is above 800r/min, the HPAM solution shows shear degradation, and when it is 12000r/min, the viscosity loss reaches by 82.3%, the mean molecular weight is decreased by 75%, the mixing speed should not be above 500r/min,the mixing time should be better to be less than 30 min. This paper also observes the shear stability when HPAM flows through different artificial core with different permeability, The degradation of HPAM is more serious when permeability is less, when HPAM flowing 0.1μm2 artificial core, the injection speed is should be no more than 11.2m3/m2?d, when HPAM flowing 0.25μm2 artificial core, the injection speed is should be no more than 22.3m3/m2?d, when HPAM flowing 0.8μm2 artificial core, the injection speed is should be no more than 30m3/m2?d, when in 1.0μm2 artificial core, the degree of influencing HPAM is lesser than others. This paper also observes the shear stability of HPAM with different molecular weight and concentration when HPAM flows through artificial core. The degradation mainly occurs when HPAM flows from the shot hole to the porous medium. The main chain of HPAM broken is the main cause that influences the degradation of HPAM, by the molecular weight is decreased, viscosity is lost. This paper offer reference data and reference for oil field.