Double-inorganic acid salt clay stabilizer for shale fracturing and preparation method thereof

The invention relates to a double-inorganic acid salt clay stabilizer for shale fracturing and a preparation method thereof. The clay stabilizer has a double inorganic acid salt complex structure of a urea derivative, and the clay stabilizer is prepared from the urea derivative and an inorganic acid through a reaction. The clay stabilizer disclosed by the invention is high in washing resistance, remarkable in clay expansion prevention effect, relatively high in temperature resistance and good in compatibility with slick water and emulsion fracturing fluid, does not reduce the base fluid viscosity of the emulsion fracturing fluid, promotes the sand carrying performance of the fracturing fluid, is applied to oil gas fracturing construction of a shale reservoir with ultralow permeability, and improves the oil extraction rate. 本发明涉及一种页岩压裂用双无机酸盐粘土稳定剂及其制备方法，所述粘土稳定剂具有脲衍生物的双无机酸盐络合结构，所述粘土稳定剂由脲衍生物和无机酸反应制备而成。本发明的粘土稳定剂耐水洗能力强，防止粘土膨胀效果显著，并且具有较强的耐温能力，与滑溜水、乳液压裂液配伍性好，不会降低乳液压裂液的基液粘度，促进压裂液携砂性能，应用于超低渗透率的页岩储层油气压裂施工，提高采油率。