CO_2泡沫压裂液两相流流动特性的试验研究

Experimental Research on the Two-Phase Flow Characteristics of CO_2 Foam Fracturing Fluid

通过大型高参数泡沫压裂液试验回路首次详细研究了实际压裂条件下CO2泡沫压裂液的流变特性,得出了实际压裂条件下CO2泡沫压裂液流变参数的计算关联式,从而为低渗油气藏泡沫压裂技术的有效实施提供了试验依据.研究表明:在实际施工条件下,CO2泡沫压裂液具有剪切稀化性质,可用幂律模型来描述;其有效粘度随剪切速率、温度的增高而减小,随压力、泡沫质量的增大而增大;相对而言,温度和泡沫质量对流变参数的影响比压力的影响明显,在该试验范围内,温度和泡沫质量对流变参数的影响呈指数规律变化.

The rheological properties of CO2 foam fracturing fluid were studied carefully under downhole conditions on the newly constructed large scale flow loop, and the correlations of rheological parameters were obtained from the experimental data, which provide the basis for reasonable selections of fracturing parameters, accurate evaluations of crack dimension and fracturing effects. CO2 foam fracturing fluid is shear thinning and can be described by power law model. The effective viscosity decreases with the increase of shear rate and temperature, while increases with pressure and foam quality. The influences of temperature and foam quality are stronger than pressure, and the rheological parameters change with temperature and foam quality by the power rule.