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.