The method for well-stimulation through a wellbore in a rock formation is hydraulic fracturing under high temperature conditions. The method includes injecting a fracturing fluid system to the rock formation; fracturing the rock formation at a temperature between 150-260 degrees Celsius; and recovering fluid components of the fracturing fluid system from the wellbore and setting the proppant in the fractures. The fracturing fluid system includes proppant and a plurality of fluid components. The fluid components can include water, a gelling agent, and a stabilizer made of ascorbic acid. The ascorbic acid stabilizes viscosity of the gelling agent, adjusts pH, and delays cross linking. Amount of components and additional components, such as a cross-linking agent, a breaker, another adjusting agent and an inverting surfactant adjust the fracturing fluid system for well conditions and a type of treatment to be completed.