Determination of the main hydraulic and poro-elastic properties of a limestone from Bourgogne, France

This study is a part of a large experimental program intended to characterise the effects of increasing temperature upon the hydraulic and poro-mechanical behaviour of a limestone from Anstrude, France. Methods of measurement as well as experimental devices, designed by our laboratory, are presented and commented on. Permeability values, measured on six different samples, either with gas or ethanol, clearly show that the results obtained with the two fluids are virtually identical as soon as the gas measurements are corrected for the Klinkenberg effect. As the permeability is not very sensitive to confining pressure variation, it can be assumed that the intact rock is slightly cracked. This is confirmed with microscopic observations as well as poro-elastic property measurements. Concerning the latter, various ways of obtaining their values are presented and compared. They include drained and undrained bulk modulus, Biot and Skempton coefficients and Biot modulus; the consistency between these parameters is finally highlighted and demonstrates that the classical theory of poro-elasticity hold very well for such a rock, which is almost monomineralic with quite a high porosity.