CO

2

gas channeling time prediction is of great significance for CO

2

gas channeling prevention and enhanced oil recovery. Current studies rarely involve quantitative characterization of the gas channeling time. According to the parameters of the target block reservoir

the crude oil viscosity

reservoir permeability

gas injection rate and injection-production well spacing and other factors impact on the moving rule of the CO

2

drive front is analyzed by the numerical simulation method

then t

he characterization formula of gas flow time and gas flow influence coefficient considering multiple factors is established

and the accuracy of the formula is verified by comparing with the field practice. The results show that under the condition of constant pressure production

the sweep efficiency decreases with the increase of crude oil viscosity. When the crude oil viscosity is greater than 3 mPa·s

the increase of gas emergence time slows down. When the reservoir permeability increases

the seepage resistance decreases

the displacement front moves faster

and the oil well breaks out earlier. When the gas injection velocity increases

the leading edge movement speed increases and the gas appearance time advances. When the gas injection velocity is 2 500 m

3

/d

the sweep efficiency is the minimum. When the injection-production well spacing increases

the moving speed of gas front slows down

and the gas emergence time of oil well prolongs. When the injection-production well spacing is larger than 250 m

the well spacing continues to increase

and the sweep efficiency increases slightly.