Assessment Of Turbulence Models For Hydrofracturing Slurry Transport Simulation In Horizontal Perforated Pipe

Abstract

Hydraulic fracture is a well stimulation process that involves injecting pressurized liquid at high velocity to initiate and propagate a fracture in the deep rock formations through which hydrocarbons are extracted [1]. Typically, the pressurized liquid, or the fracking liquid, is water mixed with sand. The water creates the fracture and the sand maintains the void open. Hydraulic fracture stimulation is a standard completion process for modern unconventional gas reservoirs. Proppant transport through the wellbore is a major consideration when a horizontal well is fractured. CFD simulation is utilized to understand the hydrofracturing process. This study is characterizing different turbulence models that can capture the hydraulic fracturing process. Selection of a suitable CFD turbulence model is carried through investigating slurry flow in a horizontal pipe and employing various turbulence models. The CFD results obtained from a Standard k-ε, Renormalization Group (RNG) k-ε and Reynold-Stress-Model (RSM) were assessed. The (RNG) k-ε model deemed the best turbulence model when capturing the slurry flow behavior. In a laboratory experiment, particle image velocimetry (PIV) was used to non intrusively measure the transportation of sand slurry flow in a horizontal see through pipeline with perforated holes. The investigation reports the results of the slurry flow patterns, the slurry flow pressure drop, the concentration profile and velocity distribution at the perforated holes. The experimental results supported the validity of the (RNG) k-ε model in obtaining reliable predictions of the slurry flow. A linear relationship between the surly velocity and the sand solid phase velocity was established.