Numerical Determination of Anisotropic Permeability for Unconsolidated Hydrate Reservoir: A DEM–CFD Coupling Method

• Published in: Journal of marine science and engineering Vol. 12; no. 8; p. 1447
• Main Authors: Li, Ruirui, Han, Zhenhua, Zhang, Luqing, Zhou, Jian, Wang, Song, Huang, Fuyou
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.08.2024
• Subjects: Air pollution; Analysis; Anisotropy; Clathrate compounds; Clean energy; Clean technology; Compaction; computational fluid dynamics; Computer simulation; Coupling; Discrete element method; Exploitation; Finite element analysis; Finite element method; Finite volume method; Gas hydrates; Greenhouse gases; Horizontal orientation; Hydrates; Mathematical analysis; Mathematical models; Membrane permeability; Methods; Natural gas; natural gas hydrate; Natural gas reserves; Numerical analysis; Numerical models; numerical simulation; Permeability; Reservoirs; Sediment; Sediments; Simulation; Simulation methods; Transport processes; South China Sea
• ISSN: 2077-1312; 2077-1312
• DOI: 10.3390/jmse12081447

Natural gas hydrate (NGH) is considered as a type of clean energy to replace coal and oil. During exploitation, permeability is one of the key parameters controlling production efficiency, reservoir stability, and greenhouse gas sequestration. Limited by experimental and numerical simulation tools, in current research, the directionality of permeability is usually ignored. In this work, a DEM–CFD coupling simulation method is developed to compute the anisotropic permeability. The sedimentary process of reservoir sediments is reconstructed, enabling the acquisition of numerical models that possess pore structures consistent with the actual fabric characteristics. The fluid transport process in various directions can be simulated with a finite element method. Taking the natural gas hydrate reservoir in the Shenhu area of the South China Sea as an example, the proposed method is validated and applied to explore the effect of compaction stress on permeability anisotropy. With the increase in compaction stress, the permeability anisotropy exhibited a rapid initial increase, followed by a sustained stabilization. The primary cause is the rearrangement of sediment particles. The non-spherical particles are driven to align in a predominantly horizontal orientation, thereby enhancing anisotropy. The proposed method provides a tool for the efficient exploitation of hydrate resources.