Mechanical properties of mudstone caprock and influencing factors: implications for evaluation of caprock integrity

Mudstone is the most common cap rock in petroliferous basins. The mechanical properties of mudstone different areas and buried depths are obviously different, which directly affects brittleness ductileness caprock its deformation characteristic. This research carried out X ray diffraction (XRD) mineral composition analysis, microscopic observation structural characteristics mechanics triaxial compression tests under conditions on six groups samples from three On this basis, establish numerical model to simulate fracture geological conditions, clarify influence factors mudstone. Compare analyze stress-strain curves after test show that, confining pressure direct factor affecting mechanism range oil gas enrichment depth. Although formation temperature has a certain deformation, effect very limited, it difficult have an essential without action pressure. also one main rock. comparison between content minerals parameters shows that transformation obvious correlation with clay minerals. Numerical simulations pore fluid important cannot be ignored overpressured caprocks. Higher can significantly inhibit transition process ductileness, at same time affect mode mudstone, great significance for evaluation integrity.