The invention relates to a
cracking viscosity reducing method and a device for
oil field ground collected and conveyed salt-containing thick oil, which are characterized in that a mode of carrying out superficial heat
cracking on the salt-containing thick oil through overheated steam is utilized, quantitative overheated steam is introduced into low water-containing thick oil, quantitative
salt resistance catalysts are added, certain
temperature and pressure are controlled in a
tower, in a certain reaction time, the superficial
cracking is carried out on the salt-containing thick oil, and the irreversible reduction of the
viscosity is realized. The pressure of a modified thick oil
cracking reaction device is 0.5MPa to 5.0MPa, the temperature is between 180 DEG C and 350 DEG C, the reaction time in the modified thick oil
cracking reaction device is 0.5hr and 4.0hr, the
mass parts of the introduced overheated steam are 5 percent to 20 percent (through being metered by raw oil), the
mass parts of the added
salt resistance catalysts are 0.01 percent to 1.0 percent (through being metered by raw oil, and the original thick oil density is greater than 0.9750g / cm<3>), the thick
oil viscosity reducing cracking conversion rate is 15 percent to 30 percent, and the
viscosity reducing rate is higher than 90 percent.