| The Shaximiao Formation in the central Sichuan region is mainly composed of delta lake sedimentation, with sand bodies vertically stacked and widely covered in the plane. However, the facies changes rapidly and there are significant differences between the longitudinal and transverse sand bodies.The engineering quality of reservoirs is closely related to actual productivity. In the tight sandstone of the SXM Formation in the Chuanzhong area, limited core samples restrict the acquisition of continuous stratigraphic profile parameters such as brittleness index and fracture toughness. Meanwhile, logging data exhibit significant indirect errors, leading to low accuracy in evaluation results. Therefore, this article takes the SXM tight sandstone as the research object. Firstly, the Fisher discriminant method is used to quickly identify the reservoir. Based on this, indoor experiments and logging data are comprehensively analyzed, integrating laboratory experiments and logging data. Through triaxial stress-strain tests, static rock mechanical parameters such as stress-strain curves, compressive strength, and maximum load were obtained. Dynamic parameters were derived from compressional and shear wave velocities in array acoustic logging data. A conversion model between static and dynamic rock parameters was established, forming a quantitative fracability evaluation method that combines brittleness and fracture toughness. The research results show that the SXM group has a compressibility index greater than 0.6, indicating good fracturability and the easy formation of complex fracture networks during fracturing. When the compressibility index is between 0.55 and 0.6, the compressibility is moderate. If the compressibility index is less than 0.55, the compressibility is poor, and during fracturing, an ideal fracture network is usually not formed, and the fractures tend to close after fracturing. This method provides an important reference for the evaluation of sweet spots in tight sandstone and fracturing operations. |
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