State;
Key;
Laboratory;
of;
Continental;
Dynamics,;
Northwest;
University,;
Xi'an;
710069,;
China;
Department;
of;
Geology,;
Northwest;
University,;
Xi'an;
710069,;
China;
Department;
of;
Geology,;
Northwest;
University,;
Xi'an;
710069,;
China;
fluid; pressure,; evolution; history,; peak; of; excess; pressure,; migration; and; accumulation; of; gas;