Numerical simulation of the conveyance characteristics of fracturing ball in the horizontal section

Ball drop-type fracturing tools that can improve permeability and production efficiency have played important roles in well stimulation during the exploitation of unconventional hydrocarbon reservoirs. In this study, computational fluid dynamics (CFD) with a standard k-ε turbulence model and a dynamic fluid body interaction model was applied to describe the coupling interaction between fracturing ball and the carrying fluid to understand the conveyance characteristics of fracturing ball in the horizontal section. The motion behavior of fracturing ball moving across the horizontal section with different flow rates and ball sizes is investigated. Simulation results indicate that the fracturing ball exhibits collision and rebound during the conveyance in the horizontal section. Minimum flow rates are required for the fracturing balls with different sizes to pass through the ball seat; otherwise, they will be trapped in the horizontal section and hardly reach the target fracturing section. On-site fracturing experiments are also conducted to validate the CFD study results. A general agreement between the numerical simulation and the on-site fracturing experiment is obtained. Therefore, these analyses have significant importance for the design of fracturing ball and fracturing parameters.