Spontaneous potential data correction

[Wingscrack]

Hello,

I am currently working on SP (spontaneous potential) data correction and i am looking for answers or references on this subject.

I know that usually this type of data is corrected using a linear function supposed to fit with the good clay distribution.

In my studied area, only 50% of the data can be corrected thanks to this way. so I tried an other way with a polynomial low that seems to correct 90% of my data.
I would like to know if in specific condition (30-50 m reservoir thickness, one typical fluid), it can be geophysically correct to use a polynomial low to correct PS data ?

Regards,
Wingscrack