Changes in viscosity of heavy crude oil treated by steam and metal salts

The conditions of aquathermolysis (ATh) in autoclave and the catalytic effect of 6 metal salts in ATh were studied for heavy crude oil viscosity of 88.3 Pa-sec at 50°C and average molar mass 654 and taken from Shuguang, Liaohe, China, to reduce its viscosity. The decrease in viscosity of the aquathermolysized oil became very small when ≥ 30 mL of water was introduced into 100 g of oil or ATh was prolonged over 36 hr and more at ATh temperature of 240°C; the viscosity of aquathermolysized oil was decreased with increasing ATh temperature from 160° to 280°C. At ATh temperature of 240°C, ATh duration of 48 hr, water volume introduced was 30 mL/100 g of oil, and concentration of metal salts in water was 0.02%, NiSO₄·6H₂O demonstrated the best catalytic effect on ATh, followed by VOSO₄ and CuSO₄·5H₂O, and Al₂(SO₄)₃, which was the worst. The viscosity of aquathermolysized oil was 32.4, 36.7, 42.6, and 52.4 Pa-sec, respectively, in contrast with 62.4 Pa-sec as blank.