A Green High‐Suspension Water‐Based Drilling Fluid Using Guar Gum–Xanthan Gum for Complex Well Drilling

The trade‐off between low viscosity and high suspension in water‐based drilling fluids is resolved by synergistic guar gum (GG) and xanthan gum (XG). A 1:1 GG/XG blend (0.3% total) at 40°C, combined with 5% sodium silicate, 0.3% PAC‐LV, and 0.5% lubricant ZWL‐1, forms the optimal formulation (4% bentonite, 0.15% sulfonated GG, 0.15% XG). It withstands 160°C aging, maintaining YP/PV = 0.33 and AV = 12 mPa·s, exceeding individual polymer limits. Biodegradability is excellent (BOD 5 /CODcr = 0.62) with no toxic/heavy‐metal additives, though ecotoxicity data are pending. Field cost is 264.18 ¥·m −3 , much lower than conventional systems. Compared to commercial WBDFs, our fluid achieves higher YP/PV (0.33–1.50) at lower viscosity (12–30 mPa·s), decoupling viscosity from suspension. This offers a cost‐effective, eco‐friendly solution for complex wells; future work includes ecotoxicity and field validation.