Different methods for determination of shale volume for Yamama formation in an oil field in southern Iraq

Abstract

The determination of the shale volume is necessary for formations properties, because it is important for computing fluid content, formation porosity and formation permeability. Different methods of determining shale volume such as Clay Indicators and Double Clay Indicators can be applied to obtain results with high accuracy. Single Clay Indicators includes several methods, the most important of which from gamma ray, Resistivity log and Neutron log. Double Clay Indicators include three methods, Density – Acoustic cross-plot, Density- Neutron cross plot and Acoustic- Neutron cross plot. The excellent way for identifying the rock formation has been achieved by using the above methods whilst determination of the magma from only one method does not reach perfect findings. Moreover, the results of these methods are closely similar which give us a confidence in the obtained findings. In this study, applying these methods in Yamama Formation in an oil field in southern Iraq that the volume of shale calculated using the gamma ray method was less than 10%, while the volume of shale calculated using the neutron method was less than 12%, and the volume of shale calculated by the Resistivity Cross plots method, it was less than 10%, and it was also less than 10% using the Sonic -Density Cross plots method, Neutron -Density Cross plots method, and Neutron -Sonic Cross plots method. The comparison of these methods shows that the volume of shale calculated by the gamma ray log was more accurate than Neutron log, because the all other methods were matched with Gamma ray log.