The ductility of a shale top seal also ''increases'' in response to increasing confining pressure. Thus, a shale with constant mechanical properties will have a lower ductility at shallow depths than at greater depth. Since a shale top seal does not have constant mechanical properties with progressive burial, compaction decreases ductility at the same time as confining pressure increases ductility. | The ductility of a shale top seal also ''increases'' in response to increasing confining pressure. Thus, a shale with constant mechanical properties will have a lower ductility at shallow depths than at greater depth. Since a shale top seal does not have constant mechanical properties with progressive burial, compaction decreases ductility at the same time as confining pressure increases ductility. |