Definition and Classification of Low-Resistivity Oil Zones

Although the analysis of the microcosmic mechanism for low-resistivity oil zones in China, the intrinsic relationship between low-resistivity oil zones and geological background is still under-developed.Based on the geology and logging analysis, we redefine low-resistivity oil zones. According to their genesis, low-resistivity oil zones can be distinguished as five different classes: low-resistivity oil zones formed by tectonic settings, by depositional settings, by diagenetic settings, by invaded settings and those which are formed by the compounding geneses respectively. We make the following observations from this study on the definition and classification of low-resistivity oil zones: 1) A low-resistivity oil reservoir has macroscopic and microscopic unity. 2) The genesis of low-resistivity oil zones varies with the type of petroliferous basin. 3) Some low-resistivity oil zones can be forecasted based on the geological study results. 4) The results in this paper suggest that well logging information is generated from two cause mechanisms, the geophysical factors and the geological setting. Future studies on the geological background cause mechanism and the theory of well logging information will enrich the theory of logging geology and improve the ability to forecast oil zones.