大庆F储层孔隙结构特征对油水相渗曲线形态特征的影响

Effect of pore structure characteristics on the features of oil-water relative permeability curves in F Formation of Daqing Oilfield

为研究孔隙结构特征对油水相渗曲线的影响,选用大庆F储层59块岩样,在相同的条件下分别进行毛管压力曲线和油水相渗曲线测定。发现根据形态特征的差异,毛管压力曲线和油水相渗曲线均可分为三类,且二者之间具有较好的对应关系。第Ⅰ类毛管压力曲线属于细歪度,孔隙分选差,毛管压力曲线中间平缓段排驱压力均大于1 MPa。对应水相下凹型相渗曲线,在三类曲线中,其束缚水饱和度最大,两相共渗区展幅和水相端点渗透率最小。第Ⅲ类毛管压力曲线属于粗歪度,孔隙分选好,毛管压力曲线中间平缓段排驱压力均小于0.1 MPa。对应水相上凹型相渗曲线,其束缚水饱和度最小,两相共渗区展幅和水相端点渗透率最大。第Ⅱ类毛管压力曲线对应水相下凸型相渗曲线位,所有参数均介于前两类之间。说明同一储层中,孔隙结构特征对油水相渗曲线的形态特征具有重要影响。

To investigate the effect of pore structure characteristics on the features of oil - water relative permeability curves,59 pieces of natural cores were used to measure the capillary pressure curves and oil - water relative permeability curves under the same conditions. According to the feature of the curves,the capillary pressure curves and oil - water relative permeability curves can be divided into three types. The typeⅠcapillary pressure curve,with fine skewness and poor pore sor-ting,has a drive pressure greater than 1 MPa,corresponding to water - downward - concave relative permeability curves. The Type III capillary pressure curve,with coarse skewness and perfect pore sorting,has a drive pressure smaller than 0. 1 MPa, corresponding to water - upward - concave relative permeability curves. The Type II capillary pressure curve is corresponding to water - downward - convex,of which all the parameters are between the former two types. Therefore,for a certain forma-tion,the characteristics of pore structure have great influences on the features of oil - water relative permeability.