Method for calculating thermal conductivity of cross-scale hydrate-containing porous medium

Abstract

The invention discloses a method for calculating the thermal conductivity of a cross-scale hydrate-containing porous medium. Thermal conductivity is a key parameter affecting the exploitation efficiency of natural gas hydrates. An existing thermal conductivity model is low in applicability to a hydrate-containing porous medium and large in calculation error. Therefore, aiming at the occurrence form of each phase in the hydrate-containing porous medium, the pore-scale hydrate-containing porous medium physical model is constructed. Based on a physical model, a pore scale heat transfer process in a porous medium is modeled, and a macroscopic thermal conductivity formula is deduced by using a Fourier law. Through comparison of a prediction result of the model and experimental measurement, the accuracy and applicability of the thermal conductivity model to prediction of different hydrate-containing porous media are verified.

Description

technical field [0001] The invention belongs to the field of heat conduction of porous media containing natural gas hydrate, and specifically relates to proposing a particle-level hydrate-containing porous media model, analyzing the heat conduction process of the model to divide heat conduction areas, and deriving heat conduction formulas for each area according to Fourier's law, thereby obtaining hydrate-containing porous media Analytical solution for the thermal conductivity of a medium. Background technique [0002] Gas hydrates have been found in large quantities in deep sea and permafrost regions since the 1960s. Gas hydrate has a high energy density, and a unit volume of gas hydrate contains up to 170 volumes of natural gas. In addition, the natural gas hydrate reserves are huge. As of 2008, the estimated total global exploration has reached 1000-10000GtC, while the total reserves of other fossil energy sources in the world, including coal, oil and natural gas, are 50...

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Problems solved by technology

The current various thermal conductivity prediction models have low adaptability in the field of hydrate-containing porous media and cause high errors, so there is a lack of thermal conductivity prediction models for the heat conduction process of hydrate-containing porous media (Dai S, Cha J H, RosenbaumE J,et al.Thermal conductivity measurements in unsaturated hydrate-bearing sediments[J].Geophysical Research Letters,2015,42(15):6295-6305.)

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