Study on proppant carrying capacities of CO₂ viscoelastic-emulsified surfactant foam fracturing fluid

Proppant carrying capacities of VES-CO₂ foam fracturing fluid were researched on the large-scale high pressure test loop. The setting and transport characters of proppant in pipeline were investigated in this paper. The cause of critical proppant settling velocity was analyzed. Effect of temperature, foam quality and proppant concentration on critical proppant settling velocity was analyzed in this paper. The results show that critical proppant settling velocity increases with the rise of temperature, while decreases with the rise of foam quality and proppant concentration. For the proppant concentration exceeds 0.25, particles start to agglomerate. Through analyzing the experimental data, experimental correlation used to calculate critical proppant settling velocity is obtained, and the maximum relative error between the calculated and the experimental results is within 15%.