Comprehensive Study Of Low Resistivity Reservoir By Logging In Dong-Han Region, Dingbian Oilfield

This paper is targeted on the genetic mechanism, evaluation methods and Macro-control factors of low resistivity reservoir in Chang 2 oil layer group of Donghan region, Dingbian oilfield. The following conclusion and creative points are made based on the firsthand information combining with Conventional logging, using different kinds of processing and interpretation methods to recognize and analyze the Complex relation of oil-water in target.The conventional log response of low resistivity reservoir is complex and takes on various forms. Its forming mechanism and controlling factors are not single, and its distribution regularity and randomness coexist. The essence of unconventional oil-water layer is high irreducible water saturation that is essentially caused by differences in reservoir properties. However, lithology is the main controlling factor. Low resistivity reservoir is distributed in relatively high clay content. From the view of the deposition phase diagram it is mostly developed on the edge of main stem. Wettability of the rock, influence of drilling fluid invasion, the additional conductivity of clay minerals and other comprehensive factors are also important factors that affect the resistivity.According to the actual situation in the region, four kinds of fast and intuitive ways of separating oil and water have been put forward:1. PSP-SP overlap graph can be used for Semi-quantitative identification of oil and water layers;2. Crossplot stepwise discriminant techniques could be used for not only explaining the oil layer, but also explaining the complex relationship between oil and water well enough;3. Crossplots of integrated parameters can accurately identify of direct oil and water layers;4. Reservoir rock pyrolysis experiment would not be affected by the resistivity. Actually, it could identify the oil and water layers with very high precision.These identification techs have different ranges of application. A comprehensive use of the four ways can effectively distinguish the complex oil-water layers. Moreover, the new identifying tech has been tested in the production process.