The start-up pressure gradient existed in the ordinary heavy oil reservoir

the seepage rules could not satisfy the Darcy

'

s rule

and the theory of conventional water production rule was difficult to apply in the ordinary heavy oil reservoirs. On the basis of non-Darcy percolation rule

and the theory of the flow tube method and the oil-water two-phase non-piston water flooding

we derived the calculation formulas of water cut and recovery degree of heavy oil reservoirs in narrow channels

and analyzed the water cut rising rules. The results showed that if the viscosity of crude oil was high

the starting pressure gradient would be great

the rate of water cut would be fast

the width of water sweep zone would be small

and the oil recovery would be low. The reasonable injection and production parameters of narrow channel reservoir could be obtained by the model

which had c

ertain guiding significance for actual reservoir development.