DEM-CFD Modeling of Proppant Pillar Deformation and Stability during the Fracturing Fluid Flowback

• Published in: Geofluids Vol. 2018; no. 2018; pp. 1 - 18
• Main Authors: McLennan, John D., Zhang, Liaoyuan, Huang, Bo, Zhang, Fengshou, Shen, Jiadong, Zhu, Haiyan, Huang, Wei
• Format: Journal Article
• Language: English
• Published: Cairo, Egypt Hindawi Publishing Corporation 01.01.2018; Hindawi; John Wiley & Sons, Inc; Hindawi Limited; Wiley
• Subjects: Analysis; Bonding strength; Computational fluid dynamics; Computer applications; Computer simulation; Deformation; Deformation mechanisms; Design parameters; Discrete element method; Dynamics; Flow stability; Fluid dynamics; Fluid flow; Fluid pressure; Fractures (Geology); Height; Hydraulic fracturing; Hydrodynamics; Instability; Investigations; Mathematical models; Mechanics; Modelling; Natural gas; Pressure gradients; China
• ISSN: 1468-8115; 1468-8123
• DOI: 10.1155/2018/3535817

In this study, proppant pillar deformation and stability during the fracturing fluid flowback of channel fracturing was simulated with DEM-CFD- (discrete element method-computational fluid dynamics-) coupling method. Fibers were modeled by implementing the bonded particle model for contacts between particles. In the hydraulic fracture-closing period, the height of the proppant pillar decreases gradually and the diameter increases as the closing stress increases. In the fracturing fluid flowback period, proppant particles could be driven away from the pillar by the fluid flow and cause the instability of the proppant pillar. The proppant flowback could occur easily with large proppant pillar height or a large fluid pressure gradient. Both the pillar height and the pillar diameter to spacing ratio are key parameters for the design of channel fracturing. Increasing the fiber-bonding strength could enhance the stability of the proppant pillar.