Terrestrial heat flow values for sedimentary basins are important for developing evolutionary models, delineating fluid expulsion pathways and assessing possible hydrocarbon maturation zones. Heat flow is the product of thermal conductivity and temperature gradient. Since the temperature gradient can be estimated seismically in hydrate bearing sediment, heat flow calculations for these sediments hinge on correctly estimating the thermal conductivity (?). Based on a suite of ? measurements made on methane hydrate and quartz sand mixtures, we have developed an effective medium theory (EMT) for a three-component system of hydrate, sediment and gas