The porositys, permeabilities, etc can be determined by standard logging suits (wireline or LWD). The pressure of a particular zone, as well as characteristic fluid samples, can be obtained similarly by FMT/RCI/MDT tools (they can determine pressures, gradients, and actually obtain representative fluid/gas samples). This data, combined with an accurate seismic tie in, will help determine how large the reservoir is, and how long the pay will last until depletion. All of this will aid greatly in determining the commercial viability of the zone in question.
Cheers, Steve