W-S model could be used to calculate the oil saturation of argillaceous sand stone reservoir.The equation is as follows: C

o

=(1/F′)(C

w

+BQ

v

)

C

t

=(S

w

n′

/F′)(C

w

+B (Q

v

/S

w

)) B is an important parameter and could be calculated according to the relation between solution conductivity C

w

and temperature T;m′ and n′ are parameters that vary with lithology;Q

v

and R

w

are basic parameters of W-S model

and could be calculated by using excited polarizing potential log data

conventional log data

formation water analysis and positive spontaneous potential curve respectively.Then use W-S model to process these parameters and the oil saturation of argillaceous sandstone reservoir could be calculated.The results are proved to be reliable and could be used to distingush between hydrocarbon reservoir and nonhydrocarbon reservoir.