Numerical simulation on the erosion characteristics of dense particles in the annular channel of downhole fracture pipe

An extra-dense volume concentration (more than 30% vol.) of two-phase flow between liquid and solid is always encountered in the narrow annular channel in the hydraulic sand fracturing technology of the oil-gas exploitation industry. Here we investigated the characteristics of erosion in the annular channel during fracturing based on the DDPM (Dense Discrete Phase Model) and a predictive model for the erosion rate of the annular channel is developed by considering flow velocity, mass flow rate, and particle size. Its indicate that as flow velocity increases, the maximum rate of erosion rises exponentially. A larger mass flow rate may lead to a decrease in the erosion rate, with a critical mass flow rate of 5.23 kg/s identified. Additionally, the erosion rate initially decreases and then increases with an increase in particle size, with a critical particle size of 0.7 mm also observed. Finally, a predicting model for the maximum erosion is proposed, the results of agrees well with available numerical simulation values. It is expected that all findings in this study can provide some guidance for predicting the erosion and operating parameters of the pipeline in the process of fracturing technology.