FSS Type V
Name: Ren Chong Fu Sheng sand type V
Self-suspending proppant Mahoney et al. [83,84] invented a novel self-suspending proppant (SSP) that can self-suspend in a carrier fluid. The proppant is made by modifying the proppant particulates with a water-swellable coating such as a hydrogel, wherein the hydrogel coating localizes on the surface of the proppant particle. The suspended proppant could be delivered to the downhole, similar to the traditional proppants.
Upon hydration and swelling of the hydrogel layer in the fracturing fluid, the hydrogel layer becomes swollen with water, such that the expanded hydrogel layer thickness can be about 10% to about 100% of the average diameter of the proppant substrate. Thus, it significantly lowers the density of the entire proppant particulates and the expanded proppant can self-suspend in the fracturing fluid without significant viscosification of the carrier fluid.
The major benefit of the SSP is better placement of proppant in the fracture leading to lower water injection requirements, lower proppant usage, and improved well productivity. However, the hydrogel coating tends to absorb moisture from the environment. As it absorbs moisture, it becomes less free-flowing. So any storage and transportation of SSP would need to be designed to prevent exposure to moisture. More work could to be done to improve the SSP handling issues.