Advancing Hydraulic Fracturing Fluids with Ascorbic Acid: A Green and Multifunctional Approach

The development of high-temperature fracturing fluids is critical as exploration extends into deeper, hotter, and lower-permeability formations. Fluid stability depends on two key bonds: cross-linker-to-polymer and monomer-to-monomer bonds. While the former can be preserved using cross-linkers and delay additives, the latter remains vulnerable to oxygen radical attacks. Conventional oxygen scavengers like sodium thiosulfate and sulfites mitigate oxidation but introduce challenges such as hydrogen sulfide (H₂S) generation, scale precipitation, and formation damage. This study evaluates l-ascorbic acid (AA) as a green, multifunctional alternative due to its antioxidative properties, acidic pH, and cross-linking delay capability. High-pressure/high-temperature (HPHT) rheometer tests were conducted on Carboxymethylhydroxypropyl guar (CMHPG) fracturing fluids at 250-300 °F for 1.5 h, while zeta potential and coreflood tests assessed formation damage tendencies. Results showed that AA reduced pH, delayed cross-linking, and enhanced fracturing fluid stability under high-temperature conditions. Additionally, its use at mildly acidic pH stabilizes clay dispersions, thereby minimizing fines migration and reducing formation damage risks. These findings demonstrate that AA is a cost-effective, sustainable additive that improves fracturing fluid performance while addressing challenges associated with conventional stabilizers, making it a viable alternative for high-temperature fracturing applications.