THERMAL PROPERTIES OF ROCKS FROM THE BOREHOLE EYREVILLE-B, CHESAPEAKE PENINSULA PRELIMINARY DATA

Thermal conductivity, thermal diffusivity, volumetric heat capacity, density and porosity were determined on 330 dry and water-saturated cores from the scientific well Eyreville-B. Non-destructive non-contact optical scanning technology was used for the thermal property measurements taking rock's thermal anisotropy and inhomogeneity into account. Porosity ranges from 0.2 to 67%. Thermal conductivity and diffusivity ranges were determined correspondingly as 0.16 to 4.76 W•m^-1•K^-1 and (0.14 to 3.90)•10^-6 m²•s^-1 for dry samples and 0.56 to 5.38 W•m^-1•K^-1 and (0.40 to 3.40)•10^-6 m²•s^-1 for water-saturated samples. Thermal anisotropy coefficient reaches 5 for dry samples and 2.7 for water-saturated samples. In most cases anisotropy was found to be caused by rock fracturing. Vertical variations of thermal properties along the well are significant (up to 50% relatively average values often) even within short intervals of depth (10-15 m) for depth interval of 1375-1762 m. Within a depth interval of 360-1090 m thermal properties are more stable. Six depth intervals in the formation can be distinguished on rock's thermal conductivity and thermal diffusivity values: 132-195 m, 213-350 m, 352-1094 m, 1099-1256 m, 1268-1368 m and from 1373 m to the well bottom. Variations in thermal properties at water-saturation are quite different within different depth intervals. For thermal conductivity the variations depend on porosity, fractures and on mineral content. Thermal heterogeneity (estimated from thermal conductivity variations within every core) is significant in most cases and reaches 20-40%.