Thermal conductivity estimation model considering the effect of water saturation explaining the heterogeneity of rock thermal conductivity

The study presents the statistical data of the effective thermal conductivity (lambda(e)) of sandstones, mudstones, and marlstones from Bavaria, Germany. The measurements were conducted by the Thermal Conductivity Scanner (TCS) for dry and water-saturated conditions at an ambient temperature and pressure. High variation in the Xe lambda(e) of sandstones is a result of the variation in matrix and pore properties. In general, the Xe increases because of water saturation. However, dissolving clay mineral found during the saturation process might explain the decrease of Xe in mudstones and marlstones in some cases. The coefficient delta lambda is used to describe the influence of water saturation on the Xe, which increases with the increasing porosity (.1)) exponentially. The variance of the delta lambda-phi-correlation and an analysis of small-scale heterogeneity revealed that water saturation also affects the thermal behavior of the matrix. Based on the measured data, the matrix thermal conductivity (lambda(m)) is calculated according to the proposed mixing model, which takes a into consideration in order to rectify the impact of water saturation on the lambda(e). (C) 2016 Elsevier Ltd. All rights reserved.