T his Final Assignment will discuss about the formation evaluation method that is chosen to calculate the water saturation in the M field. The logging interpretation itself is done in both quantitative and qualitative ways in order to determine the hydrocarbon, the shale volume, the porosity, the water saturation, moreover to select the best water saturation method for the M field. The Shale Volume (Vsh) in the M field is calculated by using the Gamma Ray logs whereas the value for the shale volume for LDA-C3 well, LDA-C4 well, and LDA-C5 well are 23.70%, 16.80%, and 7.80% in a sequent order. Furthermore, the porosity in the M field is determined with the neutron-density logs whereas the average porosity value for LDA-C3 well, LDA-C4 well, and LDA-C5 well are 9.48%, 16.45% and 21.45% respectively. Hence, by utilizing the reservoir parameters into the existing methods – Indonesian method and Simandoux method – we can determine the water saturation (Sw) value. However, the writer chose the water saturation value from the Simandoux method for this thesis because the result is closer with the core data rather than the result from the Indonesian method. By using the Indonesian method, the average water saturation result for LDA-C3 well, LDA-C4 well and LDA-C5 well are 51.34 %, 54.76 %, and 63.97 %. On the other hand, by using the Simandoux method, the average water saturation result for LDA-C3 well, LDA-C4 well, and LDA-C5 well are 32.90 %, 50.89 %, and 54.09 %.