Mechanical Properties of Carboniferous Volcanic Rock Reservoirs and Correction of Dynamic and Static Parameters

 [Objective]To address the challenges of strong heterogeneity in the volcanic reservoirs of the Carboniferous C2 formation in the Junggar Basin and the low accuracy of rock mechanical parameters derived from logging data, this study aims to precisely determine the relationship between dynamic and static mechanical parameters for typical lithologies to enhance the prediction reliability of static parameters. [Methods]Through systematic laboratory tests on four representative lithologies (andesite, basalt, tuff, and volcanic breccia), lithology-specific dynamic-to-static conversion models were established and calibrated by introducing a confining pressure sensitivity parameter. Integrated microstructural analysis via thin-section and scanning electron microscopy (SEM) observations was conducted. [Results]The results demonstrate clear quantitative relationships between the dynamic and static parameters for all four lithologies and confirm the high accuracy of the newly established, confining-pressure-corrected conversion model. [Conclusion]The analysis further reveals that the differences in macroscopic mechanical properties and dynamic-static parameter responses are intrinsically linked to specific microstructural characteristics, including mineral composition, grain structure, and pore-fracture development, confirming that the rock microstructure is the fundamental control. The calibrated model developed in this study effectively improves the prediction accuracy of static mechanical parameters, thereby providing critical technical and theoretical support for accurately obtaining these essential parameters from conventional logging data, [Significance]which is of significant practical value for the efficient exploration and development of such volcanic hydrocarbon reservoirs.