Measuring and modeling thermal conductivity of gas hydrate‐bearing sand

Abstract

Effective thermal conductivity (ETC) of both tetrahydrofuran (THF) and methane hydrate‐bearing sandy porous media was measured by the Hot Disk Thermal Constant Analyser. Thermal conductivity of methane hydrate is 0.575 W m−1K−1at 0°C and 6.6 MPa (methane gas pressure), which is close to THF hydrate's 0.51 W m−1K−1at 0°C and 0.1 MPa (atmosphere pressure). However, the measured 1 W m−1K−1ETC of methane hydrate‐bearing sand is significantly lower than that of THF hydrate‐bearing sand at ∼2 W m−1K−1. This is because the methane hydrate formed with a sodium dodecyl sulfate (SDS) solution in sand at our laboratory has a “wall creeping” growth characteristic and consequently a large part of the pores were filled with methane free gas. ETCs of sand containing gas hydrates were also calculated using a renormalization method. The process involves sample partitioning, labeling, initial value assignments, and renormalization calculations. A Monte Carlo analysis was applied to sample laboratory‐scale gas hydrate‐bearing sand assemblies. We found that the renormalization modeling results agreed well with measured ETCs when each photo of a 1.3 mm × 1.3 mm subsample was divided into 16 or more blocks.