Relevance. There are various methods of treating the near-wellbore zone to stimulate oil and gas production, the most common of which is acid treatment. The application of these methods often results in the expansion of high permeability zones due to intensive dissolution of carbonates and clays, while leaving low permeability zones unaffected. Gases (carbon dioxide, hydrocarbon gases, nitrogen, air) are specially dispersed in acid to increase the efficiency of acid well treatments. The two-phase dispersed system created in this way is called foam acid, and many of its properties are similar to those of foam. In addition, due to the two-phase nature of the formed foam acid, its effective viscosity (viscosity at a given shear stress), which ranges from 10–600 mPa·s is much higher than the viscosity of conventional acid solution (~1 mPa·s), which makes it difficult to pump into the bottomhole zone, especially in oil-saturated low-permeability formations, and also greatly reduces the coverage of formation treatment both in depth and thickness. Aim. To proposes a method of bottomhole zone treatment with gasified acid solution in subcritical phase state to improve the efficiency of acid treatment. When the volume of gaseous agent in the proposed method is selected from the calculation of full saturation of the acid solution at reservoir pressure and temperature, and the ratio of bottomhole pressure ( ) to reservoir pressure ( ) is kept below 2 ( ), a single-phase gasified acid solution in subcritical phase state with viscoelastic non-equilibrium properties is produced. Method. Laboratory experiments on injection into the reservoir model of the developed single-phase gas-acid solution with different additives of cationic surfactant. Results and conclusions. The resulting gasified acid solution flows uniformly into zones of varying permeability, increasing treatment coverage through both the thickness and depth of the formation. The use of a single-phase solution also reduces gaseous agent consumption.