致密砂岩气储层气水相渗特征及其影响因素——以鄂尔多斯盆地苏里格气田陕234-235井区盒8段、山1段为例

Gas Water Relative Flow of Tight Sandstone Gas Reservoirs and Its Influencing Factors:Case Study of Member 8 of Permian Xiashihezi Formation and Member 1of Permian Shanxi Formation in Shaan Well 234-235 Area of Sulige Gas-Field in Ordos Basin

中国鄂尔多斯盆地苏里格气田广覆性含气,但含气量差异较大。为了探讨影响气水相互作用背景下的流体运移特征,选取了陕234235井区盒8段和山1段的13块样品,基于气水相渗实验进行研究和分析。结果表明:研究区目的层位储层渗流能力较差,几乎不含Ⅰ型气水相渗曲线,具有Ⅱ型气水相渗曲线的储层是勘探开发的首选层段;可动流体孔隙度、孔隙度、可动流体饱和度、渗透率、有效孔隙体积、有效喉道体积、石英体积分数和碳酸盐岩体积分数对可开采气体的储集空间大小,即可动气体孔隙度大小,具有积极的影响,同时,上述前7种因素对气体的渗流能力,即最大有效气相渗透率,也起着积极的作用;而黏土矿物体积分数对可开采气体的储集空间和渗流能力均起着消极的作用。

The Sulige gas-field in the Ordos basin covers a wide range of natural gas,but the gas content varies greatly.In order to investigate the migration characteristics under the influence of gas-water interaction,13 samples from the 8th member of Permian Xiashihezi Formation and the 1st member of Permian Shanxi Formation in the Shaan Well 234-235 area were selected and studied based on the gas water relative flow analyses.The results show that the fluid permeability of reservoir in the target horizon is poor.The reservoirs with type Ⅰ gas-water phase permeability curve are hardly seen;while the reservoirs with type Ⅱ gas-water phase permeability curve are the preferred layers for exploration and development.The movable gas porosity equals to the storage space of recoverable g as,which has a positive correlation with movable fluid porosity,porosity,movable fluid saturation,permeability,effective pore volume,effective throat volum e,quartz volume fraction,and carbonate volume fraction.The maximum effective gas-phase permeability equals to the gas flow capacity,which has a positive correlation with the first seven factors mentioned above;while the volume fraction of clay minerals plays a negative role both in the storage space of the recoverable gas and the gas flow capacity.