Session: 11-09-02 Sustainability and Green Transition in Petroleum Industry

Paper Number: 130931

130931 - The Coupling Mechanisms of Seepage and Heat Transfer in Rock Fractures in Enhanced Geothermal Systems Based on the Lattice Boltzmann Method 

The coupling mechanism of seepage and heat transfer in high-temperature rock fractures controls the heat extraction ability of enhanced geothermal systems. Based on the lattice Boltzmann method, a numerical model for the coupling of seepage and heat transfer in rough rock fracture is proposed considering the effect of fluid temperature on its kinematic viscosity and thermal diffusion coefficient. The validity of the proposed model is verified by two classical examples. Based on the proposed model, the effect of rough fracture surface on the coupling mechanism of seepage and heat transfer was analyzed, and the relationship between the roughness of fracture surface and the performance indicators of geothermal extraction was discussed. The results show that the obstruction effect of the rough fracture surface reduces its seepage velocity, which makes the heat transfer between water and rock more sufficient, and the water temperature is higher at the outlet. As the roughness of the fracture surface intensifies, its thermal breakthrough time gradually increases, while the heat production power shows a decreasing trend. When the fractal dimension is 1.0798, its thermal breakthrough time increases by 191.49% compared to the smooth fracture, and the heat production power is only 44.36% of that of smooth fracture. In addition, the smoother the fracture surface is, the higher the heat recovery rate obtained within the same time. However, due to the its shorter heat breakthrough time, the heat recovery rate is significantly reduced at the thermal breakthrough time.

Presenting Author: Miao Li Charles Sturt University

Presenting Author Biography: Dr Miao Li is a senior Lecturer at the Charles Sturt University.

Authors:

Wei Su Kunming University of Science and Technology
Zhiliang Wang Kunming University of Science and Technology
Miao Li Charles Sturt University
Linfang Shen Kunming University of Science and Technology