珠江口盆地文昌地区珠江组一段储层泥质含量高，油层与水层的电阻率差异较小，给测井解释带来 了一定困难。 通过对研究区储层进行岩性统计分析、薄互层电阻率成像资料研究及多矿化度岩石-电阻 率实验，并综合分析各种因素对地层电阻率的影响。 结果表明：岩性细、泥质含量高、束缚水含量高和中等 地层水矿化度均是导致油层电阻率低的因素。 在明确珠江组一段低阻成因的基础上，运用三水模型评价 了该区低阻油层的含水饱和度，模型计算结果与密闭取心分析结果吻合度较高。

 The reservoir of the first member of Zhujiang Formation in Wenchang area of Pearl River Mouth Basin is characterized by high content of shale, and the difference of resistivity between oil layer and water layer is little. So it is difficult to identify the oil-bearing reservoir and water-bearing reservoir by well logging interpretation. Based on the analysis of reservoir lithology, imaging data of thin interbed and litho-electric experiment in various salinity conditions, this paper studied the impact of different factors on the formation resistivity. The results show that the main causes of low resistivity oil layer are fine lithology, high content of shale, high content of irreducible water saturation and middle formation water salinity. Based on the genesis of low resistivity, tri-water model was used to evaluate the water saturation of low resistivity oil layer in the study area. The calculation results are consistent with the sealed coring results.