A new logging interpretation method for describing the compressive and shear strength of underground tight sandstone

The mechanical parameters of rock under formation conditions mainly characterize the compressive and shear resistance of rocks in the ground. Therefore, it is of great significance to evaluate the mechanical parameters of underground rocks. In this paper, a new method for logging interpretation of rock mechanics parameters is proposed based on the Hoek-Brown strength criterion. The rock mechanics parameters explained include compressive strength, cohesion and internal friction angle. These parameters are important mechanical parameters in drilling engineering. The compressive strength represents the compressive performance of the rock, and the cohesion and internal friction angle represent the shear resistance of the rock. In the interpretation of rock mechanics parameters, the defined parameters arc assigned using the least squares method, and finally the log interpretation models of rock compressive strength, cohesion and internal friction angle under formation conditions are established. This method can comprehensively reflect the change law of the rock's failure strength under formation conditions. The parameter assignment based on the mechanical characteristics is credible. Finally, the calculated value of the model is compared with the measured value, and the error is small, which can meet the needs of the project. Therefore, this study provides a new way for logging interpretation of rock mechanical parameters of underground rocks.