Well Log Analysis
The log shown above is a completed log showing the different fluid in each layer as well as the lithology of each. The lithology can be determined primarily by the gamma ray found by the well log equipment. The lower gamma ray represents sandstone, the lower the gamma ray the purer the sandstone. The high gamma ray represents a mudstone or shale. The complete lithology is represented in eighth column. This breaks the lithology into components including coal, illite, and quartz. The fluid is determined by the resistivities and the porosity. Areas with higher resistivity (shown in column five) are areas with oil as long as the zones where there is a crossover (the red sections in the sixth and seventh columns) are present. The log was made using the program TechLog. This program does a very good job of allowing us to find different layers in the formation. To take this a step farther Techlog allows the user to correlate logs between wells in a close proximity to each other. Besides correlation these logs give a relatively good estimation for different rock properties and characteristics of the formation. Such properties include saturation of the rock, porosity, permeability, mud cake thickness, and much more.