珠江口盆地低阻油层饱和度评价方法

Evaluation Method of Saturation in Low Resistivity Reservoir in the Pearl River Estuary Basin

珠江口盆地的低阻油层具有高泥质含量、低电阻率以及低产能的特点,其真实含油饱和度的确定存在很大的困难。首先分析了区域低阻油层的地质成因,指出地层束缚水含量高,以及由此形成的发达的导电网络是导致油层低阻的主要原因;在此基础上,利用多种适合于泥质砂岩地层的饱和度模型进行计算,并根据密闭取心资料,重点分析了在不同地层条件下,对岩样含油、水饱和度进行脱气校正、压实校正、体积系数校正以及漏失校正的方法;并结合核磁共振测井,对测井计算的含水饱和度进行标定。结果显示,低阻油层的含水饱和度平均在70%以上,且印度尼西亚公式计算的含水饱和度与岩心校正后的饱和度以及核磁束缚水饱和度吻合均很好,因此印度尼西亚公式是最适合本区域低阻油层的饱和度评价模型。

The low resistivity reservoir in Pearl River Estuary basin has the characteristic of high shale content,low resistivity,as well as low capacity.It is so difficult to calculate the ture saturation of low resistivity reservoir.Firstly,the authors analyze the geologic origin of low resistivity formation,and give the main reason is the developed conductive network to high bound water content.Using several saturation models which is suit for argillaceous sandstone to calculate the saturation,and the sealing core drilling data,we show the methods of Leakage correction,degassing correction,compaction correction,volumetric factor correction at different formation conditions.And then we calibrate the logging interpretation saturation with NMR logging data.The results show that the water saturation of the low resistivity reservoir is above 70%in average,and saturation form Indonesia formula fits well to the core saturation which has been corrected and the NMR bound water saturation,so the Indonesia formula is the best saturation model for the low resistivity reservoir in this region.