东河砂岩水淹后岩石物理特性变化规律研究

为了准确确定东河砂岩水淹后储层的含油饱和度，进而判断油藏的水淹程度，以岩石物理实验为基础，系统 分析了油驱水与水驱油过程中岩电参数的变化规律，研究结果表明，东河砂岩水淹后a、m 不变化，只与岩石自身特性 有关；水淹后岩性系数（b）也基本不变，但饱和度指数（n）发生了变化，物性差时n 变小，物性好时n 变大。根据岩电 参数的变化规律，建立了变岩电参数计算模型，提高了物性较差储层的饱和度计算精度。利用不同矿化度下水驱油岩 电实验，分析了储层水淹后电性特征的变化规律，污水水淹后储层电阻率随含水饱和度的增加而降低，淡水中低水淹 时储层电阻率随含水饱和度的增加而降低，淡水高水淹或强水洗后储层电阻率随含水饱和度的增加而升高。

Study on Variation Law of Rock Physical Properties After Water Flooding#br# in Donghe Sandstone

In order to accurately determine the oil saturation of Donghe sandstone after water flooding and then determine the water flooded layer，in this paper，based on the rock physical experiment，we analyze the variation law of rock electrical parameters after water flooding with oil driving water and water driving oil experiments. The results show that a and m do not change and are only related to rock characteristics. Besides，the lithology coefficient b also does not change after water flooding，but the saturation index n has changed，which decreases in the bad physical property and increases in the good physical property. According to the variation of rock electrical parameters，we establish the computational models of rock electrical parameters which improve the computational accuracy of saturation in poor reservoirs. By water driving oil experiments with different salinity of injected water，the variation law of rock resistivity after water flooding is analyzed. It is noted that reservoir resistivity decreases with the increase of water saturation after sewage water flooding，and decreases with rising water saturation after fresh water low and middle flooding，while reservoir resistivity increases with the increase of water saturation after fresh water high flooding.