Proppant Transport Analysis of the Anionic High Viscosity Friction Reducer in High-TDS Marcellus Shale Formation Water Environments

High viscosity friction reducers (HVFRs) have been recently gaining more attention and increasing in use, not only as friction-reducing agents but also as proppant carriers. Reusing of produced water has also been driven by both environmental and economic benefits. In Marcellus Shale regions, slickwater fracturing fluids are commonly used, which reduce the number of fluid additives required and foster high retained conductivity but require high water volumes and pumping rate. In contrast, HVFRs can also exhibit high retained conductivity with less water and horsepower required and much more other operational and economical advantages. Currently, most friction reducers on the market are anionic friction reducers, which are fully compatible with most produced water with low to medium level of Total Dissolved Solids (TDS) but show significant decreasing at high TDS conditions in term of their friction reduction performance in most cases. Concerns remain about performances of using anionic HVFRs with produced water to transport proppant. The ultimate objective of this experimental study is to investigate whether increasing loading of the anionic HVFR can compensate the side effects of high TDS and temperature in Marcellus Shale formation. Anionic HVFRs at 4, 6, and 8 gallons per thousand gallons (GPT) were selected and analyzed. The rheology measurement of different concentrations of anionic HVFRs were conducted with deionized (DI) water, high TDS Marcellus Shale formation water, and 30,000 mg/L NaCl solution at temperature of 60 °C. Static and dynamic proppant settling tests were conducted with various HVFR concentrations at high TDS and temperature conditions. The results showed that high TDS and temperature decreased the viscous and elastic profiles of the anionic HVFR. In particular, the elastic profile became negligible. Differences between monovalent and divalent cations effects on the rheology properties and proppant transport capability of the anionic HVFR were also negligible at high TDS and temperature conditions. Increasing loading of the anionic HVFR had very limited effects on improving its rheology properties and further proppant transport capabilities at Marcellus Shale formation conditions. Therefore, future study can be focused on modifying proppant, such as sizes and concentrations, and slurry injection rate to get better fracturing results in Marcellus Shale formation.