Abstract: The combined use of conventional logs such as density,neutron and resistivity logs has been proven very effective in evaluating normal reservoirs. An accurate determination of the petrophysical parameters with the conventional logs for low resistivity reservoirs, however, is very difficult. This paper presents two cases of low resistivity reservoirs and low contrast resistivity reservoirs where conventional logging interpretation shows water zones, yet water free hydrocarbons would be produced. Nuclear Magnetic Resonance (NMR) has been available only as a supplement tool, to provide additional information on the productivity of the reservoir. This paper shows that in the
case of low resistivity contrast reservoirs NMR is a very cost-effective tool for helping accurately determine petrophysical properties of the reservoir.

Key words: conventional log, Nuclear Magnetic Resonance logging, low-resistivity reservoir, petrophysical parameters