The distribution of proppant in fractures is very complex. In order to support the fractures effectively, sand carrying fluid must be injected into the fractures. In this paper, effects of injection rate, proppant concentration, sand carrying fluid viscosity, proppant particle size, and the width of tertiary fractures on proppant distribution in tertiary fractures are studied. Foremost, we establish a proppant migration model in complex fractures based on the Euler-Lagrange model. Additionally, the performance of the model is examined in detail. After that, a basic case is presented to clearly understand proppant distribution in complex fractures. Finally, several simulation experiments focus on effect of different variables on proppant distribution in complex fractures. These results are helpful for optimizing proppant pumping plans for unconventional stimulation treatments.
Hydraulic fracture plays an important role in reservoir stimulation, especially for shale oil and gas with tight reservoir characteristics (Hu et al., 2018; Liu et al., 2022; King, 2010; LaFollette et al. 2014). The distribution of proppant in fractures is key factors to affect the formation of hydraulic fractures with high conductivity. However, considering influence of reservoir heterogeneity and fracturing construction conditions, the geometries of hydraulic fractures are very complex, which is affected by several elements, like whether proppant runs into the depths of fractures and fracture conductivity after fractures closing. Therefore, simulation experiments of proppant distribution in tertiary fractures are carried out in this paper. Effects of injection rate, proppant concentration, sand carrying fluid viscosity, proppant particle size, and tertiary fracture width on proppant distribution in tertiary fractures is studied. This study aims at figuring out the law of proppant distribution in complex fractures under different conditions, providing some insights on the laws of proppant distribution in complex fractures, and providing some guides for hydraulic fracturing design in petroleum engineering.
It has been widely discussed for proppant particles distribution in fracture, many scholars have carried out a lot of experimental and numerical simulation studies on proppant migration, and gained some conclusions (Song et al., 2010; Yuan, 2018; Lu and Agrawal, 2014; Zhang and Dunn, 2015). In previous experimental and numerical simulation studies, the distribution of proppant in single fracture and secondary fracture was mainly studied, while the distribution of proppant in complex hydraulic fracture networks was seldom studied. However, studies on tertiary fractures often ignored the real morphology of complex fractures underground. For example, each stage fracture is vertical, and the width of tertiary fracture is the same as that of secondary fracture. Therefore, the research results cannot fully reflect proppant distribution under condition of real fractures.