Changes

==Shale ductility and density==

==Shale ductility and density==

[[file:evaluating-top-and-fault-seal_fig10-35.png|thumb|{{figure number|1}}Data from .<ref name=ch10r37>Hoshino, K., Koide, H., Inami, K., Iwamura, S., Mitsui, S., 1972, Mechanical properties of Japanese Tertiary sedimentary rocks under high confining pressures: Geological Survey of Japan Report 244, 200 p.</ref>]]

[[file:evaluating-top-and-fault-seal_fig10-35.png|thumb|{{figure number|1}}Ductility of shale. Data from .<ref name=ch10r37>Hoshino, K., Koide, H., Inami, K., Iwamura, S., Mitsui, S., 1972, Mechanical properties of Japanese Tertiary sedimentary rocks under high confining pressures: Geological Survey of Japan Report 244, 200 p.</ref>]]

The ductility of a shale top seal is a function of compaction state. Uncompacted, low-density shales are extremely ductile and can thus accommodate large amounts of strain without undergoing brittle failure and loss of top seal integrity. Highly compacted, dense shales are extremely brittle and undergo brittle failure and loss of top seal integrity with very small amounts of strain.

The ductility of a shale top seal is a function of compaction state. Uncompacted, low-density shales are extremely ductile and can thus accommodate large amounts of strain without undergoing brittle failure and loss of top seal integrity. Highly compacted, dense shales are extremely brittle and undergo brittle failure and loss of top seal integrity with very small amounts of strain.