苏里格气区盒8段流体包裹体特征及古压力恢复

Fluid inclusion characteristics and paleo-pressure recovery of the He-8 Member in the Sulige gas field,Ordos Basin,China

以鄂尔多斯盆地苏里格气区盒8段为研究对象,通过对流体包裹体的观察、测温、测盐及组分分析等方法,厘定了流体包裹体的产状及气液比,结合埋藏史恢复了流体包裹体均一温度,并通过状态方程恢复储层古压力。研究表明,甲烷、饱和烃、CO2包裹体在愈合裂隙与石英加大边中均有发育,气液比随着油气运移距离的增大逐渐降低。石英加大边中油气的捕获时间早于愈合裂隙,两者时间存在重合,为漫长的早白垩世成藏期。天然气在源-储压差驱动下向储集层运移过程中进行压力传递,普遍发育弱超压。

The occurrence and gas-liquid ratio of fluid inclusions are determined by means of observation,temperature measurement,salt measurement and component analysis of fluid inclusions in Upper Paleozoic He 8 Member in Sulige gas field,Ordos Basin.The homogeneous temperature of fluid inclusions is restored in combination with burial history,and the reservoir paleo-pressure is restored by means of state equation.It shows that the inclusions of methane,saturated hydrocarbon and carbon dioxide are developed in the positions of healing fissures and quartz enlargement,and the gas-liquid ratio decreases with the increase of oil-gas migration distance.The capture time of oil and gas in the enlargement rims of quartz is earlier than that in the healing fracture,and the time of the two overlapped,which was a long early Cretaceous accumulation period.In the process of natural gas migration to the reservoir driven by the difference in source-reservoir pressure,the pressure is transferred and weak overpressure is generally developed.