A high-temperature-resistant and metallic-crosslinker-free fracturing fluid based on guar gum/montmorillonite nanocomposite

Abstract

A combination of moderate apparent viscosity, temperature resistance, and low damage is highly desired for fracturing fluids used in high-temperature reservoirs. The aim of this study is to achieve this combination by introducing inorganic nanolayered montmorillonite (MMT) to form a high-temperature-resistant and metallic-crosslinker-free intercalated nanocomposite fracturing fluid (GMN). The exfoliated MMT was uniformly dispersed and connected with polymer chains of guar gum to form a highly three-dimensional cross-linked network, which resulted in increased apparent viscosity and viscoelasticity of GMN compared with the guar gum fracturing fluid. Temperature resistance tests and thermogravimetric analyses demonstrated that the nanofiller enhanced the thermal stabilities of the nanocomposites, and this was attributed to three effects, including high chemical bond energies, heat barriers and minimization of chain free volumes in MMT. In the absence of a metallic crosslinker and temperature stabilizer, the resistance temperature of the GMN fracturing fluid reached 160 °C, a 40 °C enhancement compared to that of the guar gum fracturing fluid. Moreover, the GMN fracturing fluid were easily broken and exhibited a 10.34% damage rate to provide the desired fracture conductivity. It was concluded that layered MMT effectively improved the temperature resistance of guar gum fracturing fluid and exhibited great potential for use in high-temperature reservoirs.