Well log porosity versus Rock core porosity

[yiimusic]

Hello Members

Can anyone please answer me

How I can modify or arrange between well log porosity and core porosity.

I have one printed well log data which held neutoron porosity, density porosity, conductivity, and gamma ray and 17 point core porosity on interested zone.

But, well logging porosity is very different compared to core porosity.

Actually, core porosity is less than well logging one.

How can I analyze these differences?

Please guide me.

Thank you.

P.S. Total porosity of well logging data using NPHI/DPHI (for example two-third method ... ) is accurate? or not?

And, what is the major different between NPHI(Sandstone matrix) and NPHI(Limestone or Dolomite matrix)

if my interesting zone comprise mainly of sandstone and a bit of limestone, in this case I have to use NPHI(sandstome matrix) and DPHI(sandstone matrix) or not?

Please answer me.