Performance Optimization and Damage Control of Ultralow-Concentration Guar Gum Fracturing Fluids for Tight Sandstone Reservoirs

To overcome the critical challenges of inefficient flowback and secondary formation damage in low-porosity, low-permeability, and low-pressure tight sandstone reservoirs, this study presents a systematic optimization of guar gum-based fracturing fluid systems. Through rigorous evaluation encompassing crosslinking kinetics, gel-breaking efficiency, shear resistance, proppant transport dynamics, and formation damage mechanisms, an ultralow-concentration fluid formulation ($0.25 \%-0.33 \%$ polymer loading) was developed to enhance flowback performance while minimizing reservoir impairment. The optimized system demonstrates threefold technical advancements: (1) Precise crosslinking control within 40 s and complete demulsification within 2 h post-treatment; (2) A $78.67 \%$ reduction in gel-breaking residue compared to conventional formulations; (3) Exceptional thermal stability (120 °C), shear-thinning rheology ($\mathrm{n}^{\prime}=0.362-0.418$), and controlled fluid loss ($\mathrm{C}_{\mathrm{w}}=3.21 \times 10^{-4} \mathrm{~m} / \mathrm{min}^{0.5}$). Field-applicable benefits include $23.6 \%$ lower formation damage rate while maintaining effective proppant transport capacity ($\lt 0.8 \mathrm{~mm} / \mathrm{s}$ settling velocity), coupled with $34.2 \%$ cost reduction relative to standard fracturing fluids. This integrated optimization methodology establishes a technical roadmap for stimulating challenging tight reservoirs, offering significant engineering value through its balance of operational efficiency, formation protection, and economic viability.