The Primary Influence of Mineralogy on the Thermal Conductivity of Reservoir Rocks: A Comparative Analysis Beyond Porosity

Thermal conductivity is a fundamental property for modeling heat transfer in subsurface applications, including thermal enhanced oil recovery and geothermal energy assessment. While porosity is widely recognized as a first-order control on rock thermal conductivity, its predictive power is often limited due to significant data dispersion. This study argues that mineralogy is a primary controlling factor, comparable in importance to porosity. Through a comprehensive literature-based analysis, we investigate the relationship between thermal conductivity, porosity, fluid saturation, and mineral composition across diverse geological units and rock types. Data from Paleogene and Lower Triassic rocks, as well as quartzose versus clay-rich sandstones, are systematically compared. The results demonstrate that for any given porosity, a rock’s thermal conductivity is fundamentally determined by its constituent minerals. Lower Triassic rocks, presumed to be rich in high-conductivity minerals like quartz, exhibit significantly higher thermal conductivity than their lower-conductivity, clay-richer Paleogene counterparts. Similarly, clean quartzose sandstones are more conductive than sandstones with shale interbeds. The analysis also confirms established principles, such as the inverse relationship between thermal conductivity and porosity, and the higher conductivity of water-saturated samples compared to gas- or oil-saturated ones. This study concludes that overlooking mineralogy leads to substantial inaccuracies in thermal modeling. A robust prediction of thermal conductivity requires a quantitative understanding of the rock matrix composition, moving beyond simplified porosity-based correlations to improve the reliability of reservoir simulations and geothermal assessments.

کلیدواژه ها:

Thermal Conductivity ، Reservoir Rock Properties ، Mineralogy ، Petrophysics