## 3 Samples and Experimental Methods
### Pore Structure Characterization Experiments  
XRD analysis can determine the relative abundance of different minerals in tight sandstone, especially clay minerals. In this study, a D8 AA25 X-ray diffractometer with Cu-K\(\alpha\) radiation was employed for detection. Samples were oven-dried at 60 \({}^{\circ}\)C for 48 h, ground to a particle size less than 40 \(\upmu\)m, and pressed into pellets using a back-pressure method. The computer-acquired diffraction spectra ranged from 3\({}^{\circ}\) to 45\({}^{\circ}\). The porosities and permeabilities of 62 tight sandstone reservoir samples in Es\({}_{3}\)[3] from drilling wells were systematically measured and collected. The porosities of the thoroughly dried samples were measured using a JS 100007 helium porosity measurement instrument, with high-purity helium (99.99%) chosen as the working medium for porosity measurements. The measurement principle is based on [PERSON]'s gas expansion law. The helium method reveals only connected porosity rather than total porosity. In this study, the JS 100007 helium porosimeter exhibited an RSD of 0.73%, a triplicate-measurement RSD\({}_{\text{triplicate}}\) of 0.717%, a porosity measurement accuracy of \(\pm\)0.02% (of true value), and a pressure sensor accuracy of \(\pm\)0.1%. The permeability parameters were obtained using an A10133 gas permeameter by standard industry methods with a confining pressure of 5 MPa. The measurement principle is based on [PERSON]'s law. The A10133 gas permeameter demonstrated an RSD of 1.21%, a triplicate-measurement RSD\({}_{\text{triplicate}}\) of 1.15%, a flow meter and differential pressure sensor accuracy of \(\pm\)1-2%, and an additional calibration error of 1-2%. Casting thin sections were created by injecting evacuated pore spaces with blue resin of rock samples to visualize pore types and sizes. Carbonate minerals were differentiated via Alizarin Red staining. After the resin solidified, the samples were cut and polishedusing the French Brot CTS sample preparation system (Zhehong Robot Automation Company, Shanghai, China). A total of 62 casting thin sections covering different sedimentary facies in the study area were prepared and observed via LinKam-350 polarizing microscope (Linkam Scientific Instruments, Redhill, UK) to distinguish minerals, cement types, and pore genesis and types. Rock types were determined according to core and casting thin section observations, XRD identifications, and rock mineral compositions. Based on the identification from casting thin sections, we analyzed the sandstone samples using a CL8200 MK5-2 cathodoluminescence instrument (Cambridge Image Technology Ltd, Hatfield, UK) to determine the types and extent of diagenesis, such as feldspar dissolution and calcite cement. The experimental conditions were a temperature of 25 \({}^{\circ}\)C, humidity of 45%, vacuum of 0.3 Pa, beam voltage of 13.5 kV, and beam current of 250 mA. ZEISS SIGMA500 field emission SEM (Carl Zeiss Microscopy GmbH, Oberkochen, Germany) with a maximum resolution of 1 nm was used to observe selected tight sandstone reservoir samples under the control of different sedimentary systems and to determine the pore type, morphology, mineral type, size, and occurrence of the pores to study the pore structure [45]. Prior to observation, samples were sliced into thin sections, with observation surfaces of argon-ion polished and gold-coated to enhance sample conductivity. The pore morphology and mineral elemental composition were observed using secondary electron detectors and EDS. Additionally, different types and forms of pores significantly differ from mineral particles after argon-ion polishing, allowing pores to be directly acquired via ImageJ software (Basic Class). The application of this software for quantifying pore structures involves obtaining binary images of pores, as well as the pore diameter, pore area, and porosity parameters.