Some Thermal Characteristics of Porous Rocks

Abstract

Published in Petroleum Transactions, AIME, Volume 213, 1958, pages 375–378. Abstract Results of experimental measurements of heat capacities and thermal conductivities of some typical porous rocks are presented. Measured heat capacities agree closely with values calculated from known chemical compositions of the rocks. On the basis of this agreement, heat capacities of fluid-saturated rocks were calculated. Thermal conductivities of the rock samples were measured under various conditions of fluid saturation. From these data thermal diffusivities were calculated. A significant variation of thermal diffusivity with temperature is indicated. Introduction Knowledge of the thermal characteristics of fluid-bearing porous rocks has become increasingly important with the development of thermal oil-recovery processes. Reliable thermal data for petroleum reservoir rocks are not available and approximate values are generally assumed for reservoir calculations. The effects of temperature, pressure and fluid saturation on thermal properties of porous rocks have not been carefully studied. The purpose of the present work was to measure and report the thermal characteristics of some typical porous rocks. A group of eight sedimentary rock samples, including limestone, shale, sandstone and siltstone, was selected for the study. Properties reported include heat capacities, thermal conductivities and thermal diffusivities. The effect of fluid saturation on these properties was also considered. Determinations of thermal properties require precise measurements which are time consuming and difficult to reduce to a routine basis. Methods have not been developed for measurement of thermal properties under conditions of pressure, temperature, and fluid saturation, which may be encountered in thermal recovery processes. As one approach to these problems, some preliminary work on methods of estimating thermal properties from other more readily measurable characteristics of the rock-fluid system is reported.

Crustal composition and mantle heat flow: Implications from surface heat flow and radiogenic heat production in the Variscan Erzgebirge (Germany)

“…Assuming 1% porosity as a typical effective porosity value, the ratio of the thermal conductivity of water-and air-saturated rock ( ,v n, /•'wsat/•.asat) yields 1.03. This value is in the range of values known from empirical observations in sedimentary rocks [Somerton, 1958]…”

Physical properties of Mohole test site basalt

“…However, there was insufficient sample of the basalt to predetermine reaction temperatures and it was necessary to run the 0. 30 I I I I I I I I I o Specific heats were calculated by application of Kopp's law to an oxide analysis of the basalt [Somerton, 1958], and the results are shown in fair agreement with nonsteady-state data (Figure 4). To calculate conductivities from diffustytry data, a curve for diffusivity without reactions was estimated.…”

Geothermal characteristics of the Ries impact structure

“…The dependence of thermal conductivity on different factors (porosity, fracturing, mineralogical content, structural-textural properties) has been studied previously by many researchers, e.g. Somerton (1958), Robertson (1979), Zimmerman (1989), Brigaud (1989), Horai (1991), McKenna et al (1996) and Schön (1996). The results have shown a significant influence of porosity on rock thermal conductivity.…”