Numerical investigation of non-uniform temperature fields for proppant and fluid phases in supercritical CO2 fracturing

• Published in: Particuology Vol. 90; pp. 149 - 163
• Main Authors: Liu, Boyu, Yao, Jun
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.07.2024
• Subjects: CFD-DEM; CO2 sequestration; Compressible fluid; Heat transfer; Proppant transport; CFD-DEM; CO2 sequestration; Compressible fluid; Proppant transport; Heat transfer
• ISSN: 1674-2001; 2210-4291
• DOI: 10.1016/j.partic.2023.12.002

The non-uniform temperature distribution in supercritical CO2 (Sc-CO2) fracturing influences the density, viscosity, and volume expansion or shrinkage rate of Sc-CO2, impacting proppant migration. This study presents a coupled computational fluid dynamics-discrete element method and heat transfer model to examine the effects of proppant bed shape and the heat transfers of proppant-wall, proppant-fluid, and fluid-wall on the fluid and proppant temperature fields. The Sc-CO2 volume expansion is assessed under various temperature conditions by evaluating the volume-averaged Sc-CO2 density. Several factors, including proppant size, shape, thermal conductivity, concentration, temperature difference, and injection velocity, are carefully analyzed to elucidate their impacts. The findings elucidate the existence of four distinct zones in the fluid temperature field. Each zone exhibits different magnitudes of temperature change under diverse conditions and undergoes dynamic transformations with the development of the proppant bed. The fluid-wall heat transfer and the fluid temperatures in Zones C and D are significantly subject to the fluid injection velocity (governing the heating duration), the temperature difference between fluid and formation (impacting the magnitude of heat flux), and the proppant bed shape (controlling the effective heating area). Additionally, the proppant-wall and proppant-fluid heat transfers determine the temperatures of both the proppant bed and the fluid within Zone B, showing a strong correlation with proppant thermal conductivity, proppant size, injection velocity, and temperature difference. The proposed coupled model provides valuable insights into the temperature distributions and flow behaviors of temperature-dependent fracturing fluids and proppants. [Display omitted] •A coupled computational fluid dynamics-discrete element method and heat transfer model is employed.•Temperature fields for fluid and proppant phases are accurately characterized.•Proppant–wall, proppant–fluid, and fluid–wall heat transfers are evaluated.•Effects of proppant bed shape on the temperature fields are investigated.•SC-CO2 volume expansion under various conditions is assessed.