Experimental study of degradable fibers as a proppant transport agent

Abstract

Hydraulic fracturing with slickwater is a common practice in developing unconventional resources in North America. The proppant placement in the fractures largely determine the productivity of the well as it affects the conductivity of fractures. Despite the wide use of the slickwater fracturing and the importance of the proppant placement, the proppant transport is still not fully understood and the efficiency of the proppant placement is mostly bound to the changes to proppant properties, friction reducers, and guar technology. The trend is that the industry will continue using a large amount of proppants per fracture operation as long as the transport mechanics is not fully understood, which is the motivation for pursuing research related to the proppant transport. Although the degradable fiber is currently used in some cases to enhance the proppant transport, it has not been well investigated in a large-scale experimental set up. In this experimental study, we constructed three types of proppant transport slot equipment to conduct proppant transport experiment using different fluid composition of fiber and guar gum to test the proppant transport in the presence of fibers. Specifically, the proppant fall behavior and the horizontal transport behavior are studied. The experiments showed the distinct difference in transport mechanism in presence of fiber. The results indicate that the use of degradable fibers with or without the guar gum as viscosifiers can produce fracture slurry applicable in helping proppant placement in the reservoir for conventional and unconventional reservoir. Lastly, the fracture simulation study is performed with a 3D hydraulic fracture commercial software, StimPlan™ by NSI Technologies. The simulation study focuses on the effect of fiber on fracture geometry and the proppant transport using fibers. The simulation is carried out with the experimental data on the degradable fiber that is used for the experiment. The numerical simulation study shows that the inclusion of fiber would yield different result compared to the base fracture fluids commonly used for the slickwater fracturing.