Preservation conditions of shale gas in Longmaxi formation of Dingshan area

Dingshan area in southeastern Sichuan is characterized by complicated geological structure.Through the research of structural evolution features and the analysis on distribution features of fold fracture development,combined with buried depth,reservoir pressure,roof and floor conditions getting by geophysics methods,the research on preservation conditions of shale gas in Wufeng-Longmaxi formation of Dingshan area was carried out.In reference with the evaluation indexes of preservation conditions of shale gas,the favorable area for shale gas preservation was classified.The results indicated the late tectonic reconstruction dominated by denudation and faulting were the major factor leading to the dissipation of shale gas.There were less fractures in slope area of fault-folded structure and syncline structure,with good preservation conditions such as moderate depth,higher formation pressure and stable cap rocks,which was the favorable target for further exploration and development.