Study of a Novel Thermoviscosifying Polymers Fracturing Fluid Based on Supramolecular Self‐Assembly

Abstract

ABSTRACT Nowadays, the exploration of unconventional reservoirs commonly faces the challenges brought by harsh natural reservoir conditions such as high temperature and high salinity. This research proposes and tests a novel thermoviscosifying polymer‐based fracturing fluid (HTEP) through combining natural reservoir conditions with polymer structural characteristics. HTEP is highly sensitive to environmental salinity that the existence of salt would initiate a transition in the self‐assembly mode between polymer molecules. This unique feature not only helps to adjust the viscosity of the fracturing fluid, making it easier to pump, but also enhances the thermal‐thickening effect, improving the fracturing performance of the fracturing fluid. Rheological tests reveal that HTEP possesses excellent shear‐thinning properties with the occurrence of stress decay, while thermos‐shear measurements show that at 100 s −1 and 100°C, the viscosity retention rate of HTEP solution is 80.49%, exhibiting high thermos‐shear stability and thermos‐thickening property. Molecular dynamics simulations reveal that with increasing system temperature, the associative interactions among polymers are enhanced, explaining the thermoviscosifying behavior of HTEP and its stability at elevated temperatures. Therefore, taking into account the above characteristics, this HTEP fracturing fluid has good potential for field applications.