Analysis on micro-geological causes of low-resistivity oil layers from Member 1 of Zhujiang Formation in Qionghai uplift

The types of rocks containing low-resistivity oil layers from Member 1 of Zhujiang Formation in Qionghai uplift are quartz sandstone and feldspar-quarz sandstone,characterized by high mud,low carbonate mineral cementation and high-mederate porosity,with mederate-low permeability.The reasons to low-resistivity of oil layer forming include ① lithologic characters are argillaceous siltite and fine sandstone and silt mudstone interbedding,with fine grains of sandstone;② clay minerals are mainly illite /smectite and illite,growing on the surface of grains forming clay coating;③ the teroat facture is mainly micro-throat.Little of electric mineral contribute to low-resistivity of oil layer slightly.