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. During a fracturing treatment, a pair of main fractures firstly is generated perpendicular to the wellbore direction. As the fluids continue to pump, more micro-sized fractures are generated near the main fractures. 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 attempts to represent how this solution flows in microfractures by considering how it flows in microchannels. A commercial friction reducer was prepared with deionized water. The size of the particles in the FR first was analyzed from the macro to the nano scale. Then, the FR solution fluxed the microchannels with various velocities. Different solution concentrations, microchannel size effects and Reynolds number (Re) were investigated in detail. The Microchannels wettabilities, fluid shear rates and residual resistance factors also were studied. Finally, the experimental results were compared with field data, and its impact on the gas shale matrix was analyzed.