As we all know, petroleum directly or indirectly provides valuable resources for social development. HEC thickens, suspends, disperses, emulsifies, binds, forms film, and provides protective colloids. The role of oil drilling is also obvious to all. HEC has excellent salt tolerance, high viscosity, high shear rate, and reduced water loss, which can improve the stability of the wellbore, and make the uneven rock formation in a stable state. It improves the rock carrying capacity, limits the diffusion of drill cuttings, prevents damage to the production layer, and greatly increases the drilling speed and oil production.