A Novel Nanotube/VES-Based High Temperature High Pressure Fracturing Fluid

Abstract

Abstract Viscoelastic surfactants (VES) were introduced to apply in hydraulic fracturing fluids as a proppant carrier in order to replace polymers which possess high potential for formation damage. Yet, VES technology is limited by its low thermal stability and high leak-off behavior in high permeability formations. This study aims to design a novel VES based hydraulic fracturing fluid assisted by functionalized carbon nanotubes (CNT) to enhance its rheological properties and extend its thermal stability. Two types of VESs were tested in the present study. Viscosity measurements were conducted on the VES/CNT system with different concentrations of CNT to characterize the rheological properties of the system. Thermal stability of tested systems were evaluated using Nuclear Magnetic Resonance (NMR) spectroscopy. To understand the nature of the VES interactions with nanotubes infrared (IR) spectroscopy was conducted. The results of rheological measurements demonstrate that addition of trace amounts of CNT, 0.04 to 0.2 wt%, to the solution of 6 wt% VES would enhance the rheological behavior (viscosity and elasticity) of tested VES systems by 40%. IR spectroscopy experiment was carried out to determine the functional groups that are involved in the interaction of CNT and viscoelastic surfactants. These results denoted that amide is the main functional group that can interact with CNT through hydrogen bonding and causes alternation of micellar structures due to change in the repulsion forces between surfactants headgroups. These findings were further confirmed by the results of NMR analysis. The nanomaterial-enhanced fracturing fluids based on VES exhibit numerous advantages over conventional polymeric or VES-based systems including high-temperature performance, non-damaging nature, and low additive loading.