Three-Dimensional Investigation of Particle Agglomeration using PIV

Proppant placement and settling characteristics significantly impact fracture conductivity. One key measure of reservoir permeability lies in proppant concentration at fractures. Despite its importance, minimal attention has been given to understanding the complex proppant agglomeration mechanisms, especially from a three-dimensional aspect. While two-dimensional studies indicate an inverse correlation between fluid viscosity and agglomeration, agglomerate forming mechanisms in a settling slurry are still ambiguous. The present study utilizes a combination of high-speed imaging and particle image velocimetry (PIV) to investigate the fundamental proppant agglomeration mechanisms in a three-dimensional domain. Multiple mesh size proppants are released in a rectangular transparent cell setup filled with varying solution viscosities. Addtionally, this study aims to identify an optimal proppant mesh size mixing ratio and fluid viscosity to facilitate hindered settling. Two high-speed cameras are set up for a full two-plane proppant PIV analysis and accurate agglomeration quantification. Preliminary results indicate unique agglomeration patterns associated with each solution viscosity and the existence of an optimal viscosity for reduced settling velocity with minimal agglomeration.