Measuring formation porosity and permeability

A method of estimating characteristics of a core sample in a borehole comprising:

• (a) obtaining the core sample with a coring tool in the borehole and immersing the core sample in a fluid;
• (b) generating acoustic waves in the fluid and at a frequency that is substantially equal to a resonant frequency of the core sample;
• (c) obtaining an attenuation factor of pressure of the acoustic waves in the fluid over time;
• (d) obtaining a spectral component of pressure in the fluid at a first resonant frequency from at the acoustic waves;
• and
• (e) estimating at least one of porosity or permeability of the core sample based on the attenuation factor and the spectral component.

A system for estimating characteristics of a core sample in a coring tool in a borehole comprising:

• an elongated bore in the coring tool that selectively receives the core sample, the core sample immersed in fluid;
• a transducer in the bore that at least partially circumscribes the core sample and selectively oscillates at about a resonant frequency of the core sample;
• an acoustic receiver disposed in the coring tool that selectively receives acoustic waves generated by the transducer;
• and
• a processor for estimating a value for at least one of a porosity or permeability of the core sample based on an attenuation factor of pressure of the acoustic waves in the fluid over time received by the acoustic receiver and a spectral component of pressure measured in the fluid at a first resonant frequency of the core sample.