Mechanisms for stabilizing and supporting shale fractures with nanoparticles in Pickering emulsion

Slickwater hydraulic fracturing technology is widely used in shale reservoirs to form complex networks and improve hydrocarbon recovery, but the proppant cannot be delivered to the remote fractures due to its low viscosity. Pickering emulsion stabilized by nanoparticles is developed as a hydraulic fracturing fluid for shale reservoirs. In this study, nano-silicas were used to prepare and stabilize Pickering emulsion. During fracturing process, this emulsion is broken to release nano-silicas, which would adsorb on fractures surfaces or assemble in fractures. The nano-silicas in low mass concentration Pickering emulsion pave on the surfaces of shales uniformly, hence stabilize the shale and prevent clay hydration. And when in high mass concentration Pickering emulsion, nano-silicas can accumulate in fractures to support and prevent them from closing. Since Pickering emulsion itself contains nanoparticles to serve as proppants, it can penetrate the entire fracture and complex network which maximize the effective fracture area and stimulate reservoir volume, furthermore replacing traditional proppant pumping.