Back To Introduction to Heat Flow Exploration

Thermal Conductivity

At any point in the sediment column, the measured heat flow is the product of temperature gradient and thermal conductivity. The sediment thermal conductivity is mainly controlled by the water content of the sediment, since the thermal conductivity of water, 0.6 W/m-K, is much less than that of the rock matrix, which might typically be 2.3 W/m-K. For example, the thermal conductivities of Gulf of Mexico deep water stations, shown in Figure 4, typically range from 0.85 to 1.1 W/m-K, consistent with a variation in porosity from approximately 75 to 55% for the above assumed rock matrix thermal conductivity. The maximum thermal conductivity, of approximately 1.6 W/m-K, is consistent with a porosity of 25%. These measurements are accurate to 1% of value, so the measured variations are factual. The next most significant factor determining the thermal conductivity of the sediments is the amount of quartz in the sediments, since the thermal conductivity of quartz is very high.

Figure 4. Thermal conductivity profiles in the sediments at each station.