Comparison of thermal and elastic properties of sandstones: Experiments and theoretical insights

Abstract

We measured P-wave velocity, thermal conductivity and thermal diffusivity on 26 sandstone samples under dry and water-saturated conditions. Subsequently, we compared these measurements with predictions by frequently used models.Overall, these three properties decrease with porosity and increase with water saturation. Comparing data sets and models, we distinguish three main groups of sandstone samples: From the difference in the intrinsic elastic and thermal properties of the dominant mineral, two tendencies attributed to either quartz or another rock forming mineral are identified, which separate class 1 sandstone and samples from class 2 sandstones. Within class 1 clean sandstones, a sub-class (sub-class 1a) consists of similarly porous samples having different elastic and thermal properties. Based on elasticity, we attribute this effect to microcracks or grain contacts in the samples. While this feature does not affect the total porosity, it affects all of three physical properties strongly and in a similar way. Additionally, we define a second sub-class (sub-class 1b) for Fontainebleau sandstone with porosities above 13%. For these four samples, the effect of water saturation on the elastic and thermal properties is different.