An Experimental Investigation of the Critical Flowback Velocity in Hydraulic-Fracturing Shale Gas Wells

The loss of proppant in flowback process has been a problem in hydraulic fracturing treatments for many years. As the pumping pressure is released at the end of a fracturing treatment, the proppant remains in the fractures, holding them open and forming conduits for fluid to flow into the wellbore. If the proppant flows back into the wellbore, the thickness of the fracture limits the flow-channel conductivity, choking the production potential of the well and impairing the effectiveness of the fracture treatment. A well cleanup is often required to remove the unwanted proppant from the wellbore to re-establish production from the entire perforated interval. This paper highlights on what is the critical flow rate that can carry the proppant out in different confining pressure and various Cross-Sectional Area of the fractures.