Tight formations with extremely low matrix permeabilities, such as gas shale, can produce at economical rates is due to inborn fissures and fractures introduced during hydraulic stimulation. Hydraulic fracturing in gas shale can connect/generate these microfractures, causing them to become much more complex fracture networks. These microfractures have much more contact area with the matrix and therefore hold the majority of the productivity potential of gas shale. Slickwater fracturing has been proved to be an effective method by which to increase the recovery of shale gas reservoirs. Friction reducer is the primary component of this fluid. It can decrease the flowing friction in macro tubing. Lab tests and field applications have addressed this issue thoroughly. However, the flow characteristics of this solution in microfractures are not clear. The present study will show how this solution flows in microfractures by employing micro-sized fracture model. FR solution is a shear thinning fluid. Rather than reducing flow friction, with the FR fluid in a 1000 μm height, 50 width μm and 4.14 cm length microfracture, the injection pressure did not decrease but rather increased 36%. The impact of FR solution concentration was found to be more obvious at low velocities. At the same shear rate, the apparent viscosity is higher in large microfractures. At the same velocity, large microfractures have higher residual resistance factors. Through the analysis of fluid emulsion particle size and shale matrix pore size, this FR solution will not go into the matrix pores easily, but can block the pore entrance to prevent the fluid from leak off and to protect the formation from contamination during slickwater fracturing.
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