A New Friction-Reducing Agent for Slickwater Fracturing Treatments

Abstract

Abstract Friction reducers (FRs) represent an essential component in any slickwater fracturing fluid. While the majority of the previous research focused on evaluating the friction-reduction performance of these chemicals, only a few studies addressed the potential damage these chemical can cause to the formation. Because of the polymeric nature of these chemicals (typically PAM, polyacrylamide), a friction reducer can either filter out onto the surface of the formation or penetrate deeply to plug the pores. In addition, breaking these polymers at temperatures lower than 200°F remains a problem. This work introduces a new and non-damaging friction reducer that can be a replacement for liner gel with enhanced proppant-carrying capacity. Friction-reduction performance, proppant settling, viscosity, and coreflood studies were conducted with the following objectives: (1) investigate the effect of using the new FR on the permeability of tight sandstone formation compared to two conventional FRs, (2) test the performance of the new FR in different salinity environments from fresh to saline water, and (3) examine the effectiveness of breaking the new FR using different breakers. The friction reduction of the new chemical was higher than 65% in fresh water or 2 wt% KCl in the presence of calcium chloride or choline chloride. The presence of 1 gpt of different types of breaker did not affect the friction reduction performance. The friction-reduction of 1 gpt of the new FR1 was higher than the guar-based FR3 at load of 4 gpt at the same conditions. The results also showed that the new friction reducer is easily breakable in any of the three tested breakers: ammonium persulfate, sodium persulfate, and hydrogen peroxide. Among the three, ammonium persulfate was the most efficient breaker. Static and dynamic proppant settling tests indicated a superior performance of FR1 compared to another conventional polyacrylamide friction reducer (FR2). Coreflood experiments showed that the new friction reducer FR1 did not result in any residual damage to the formation permeability compared to 10 and 7% damage when the other two conventional friction reducers FR2 and FR3 were tested, respectively. Coreflood tests also showed that the new friction reducer is breakable using a weaker breaker such as sodium bromate with a minimum of 2.5% damage. The results showed that higher salinity did not affect the breakability of the new friction reducer.