Abstract: Based on the features of the two types of reservoirs, the characteristics of lithological and physical properties, pore structures and their differences between high-and low-resistivity oil layers are studied for the purpose of effective identification of such oil layers in Well Tai-60. It is suggested that the origin of low-resistivity oil layers is the relatively high irreducible water saturation and high content of illite-montmorillonite mixed-layer minerals. And the low well log response differences between these oil layers show that the well log response of low-resistivity oil layers is similar to those of neighboring mudstones and dry layers. These results are not effectively used to identify the low-resistivity oil layers with conventional logging methods. This paper presents the method by well logs, overlapping densitysonic and density-compensated neutron logging curves, integrated with the relatively relationships among the three resistivity curves as well as the geochemical indices for effective identification of the low-resistiveiy oil layers. The production test data indicate that this method can be used to realize the fast-identification of low-resistivity oil layers.

Key words: oil layer, irreducible water saturation, resistivity, well log response