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

Liu, B., & Yao, J. (2024). Numerical investigation of non-uniform temperature fields for proppant and fluid phases in supercritical CO2 fracturing. Particuology, 90, 149-163. https://doi.org/10.1016/j.partic.2023.12.002

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

Boyu Liu, Jun Yao^*

Research Center of Multiphase Flow in Porous Media, China University of Petroleum (East China), Qingdao 266000, China

10.1016/j.partic.2023.12.002

Volume 90, July 2024, Pages 149-163

Received 22 June 2023, Revised 18 November 2023, Accepted 4 December 2023, Available online 13 December 2023, Version of Record 5 January 2024.

E-mail: rcogfr_upc@126.com

Highlights

• 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.

Abstract

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.

Graphical abstract

Keywords

CFD-DEM; Heat transfer; Compressible fluid; CO₂ sequestration; Proppant transport

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