Effects of Longmenshan earthquake on migration and accumulation of natural gas in west Sichuan basin

This massive earthquake,which occurred in the Wenchuan town on May 12,2008,tore open at an instant with a 300 km-long broken zone of rocks in the internal information of the Longmen mountain,not even to mention those aftershocks for more than 37,800 times,and thus inevitably changed the formation pressure drainage system.It is a concern for all what effects this earthquake has on the migration and accumulation of natural gas in west Sichuan basin.Therefore,through analysis on the relationship between the migration of underground fluids and the earthquake characteristics and ruptures,this study concludes that the Longmen earthquake performs control functions in the migration and accumulation of natural gas in west Sichuan basin,on which a conceptual model is proposed here.Based on this model,this study put forward that due to this earthquake oil and gas in those nappe formations will scatter and natural gas in west Sichuan depression will outbreak to generate in deep and accumulate in shallow reservoirs.This model can well interpret the features of natural gas reservoiring in west Sichuan basin,hopefully providing references for further oil and gas exploration there.