<p>In order to improve the development effect of low-producing wells in dense sandstone reservoirs in Yinger Depression, an indoor acidification and production increase experimental study was carried out under simulated stratigraphic conditions to address the problems of poor pore permeability, low differential pressure, and weak efficiency of acid reaction. Representative core samples were selected, and a 12% HCl + 3% HF composite acid system was used at 80°C and 10 MPa to carry out a dynamic acidification test through a high-temperature and high-pressure core replacement device, which was combined with nuclear magnetic resonance (NMR), ICP-OES, XRD, SEM and other means to quantitatively analyse the changes in the physical properties of the core and the reaction products. The results showed that the porosity of the core was increased from 7.2% to 9.8% after acidification, and the permeability of was increased from 0.062 mD to 0.325 mD; the dissolution rate of the core was 6.3% on average, and the concentrations of Ca²⁺ and Mg²⁺ ions in the reaction solution were increased from 0.3 and 0.1 mmol/L to 3.3 mmol/L, respectively. XRD test showed that the content of carbonate minerals such as calcite and dolomite decreased significantly after acidification; SEM observation showed that the expansion of the pore throat structure on the core surface was significant, forming non-homogeneous wormhole-like channels, which helped to improve the seepage capacity. Low-field nuclear magnetic resonance analysis showed that the volume percentage of small and medium-sized pore throats increased by about 18.7% after acidification. The study shows that the acid system has good reservoir reforming ability, which provides an important experimental basis and theoretical support for the optimisation of the acidizing process in low-producing wells in Yinger Depression, and has good value for on-site promotion and application.</p>