A New Type Microproppant and Its Property Evaluation for Shale Gas Reservoirs

Modern hydraulic fracturing technologies relied on maintaining the natural fracture of the shale reservoir open and providing its longterm conductivity by injecting flow with proppant particles of various sizes. However, some natural fractures were too narrow for the conventional macro- sized proppants to enter, which greatly reduced the gas flow area and productivity and implied an increasing demand for micro- sized proppants that could be easily transported in narrow natural fractures. This study introduced innovative microproppants produced from abandoned tailings. Their basic characteristics were experimentally obtained, and the impact of various factors on microproppant placement and transportation in fractures was analyzed using a physical analog fracture model. The performed field and laboratory tests proved that this microproppant combined the merits of low activity, low cost, and easy utilization in the petroleum field. Besides, in the experiments of prefabricated fractures, the permeability of fractures filled with this type of microproppant exceeded that of fractures with no microproppant under temperature variation from 30 degrees C to 90 degrees C. Finally, visual examination of prefabricated fractures showed that the transport capacity of this new type of microproppant significantly outperformed that of the microproppants made of quartz sand and ceramic with the same particle size.