IPA CONVEX 2014

Water Saturation Modeling in Transition Zone without SCAL Data Using Cuddy’s Height Saturation Method Case Study of Moza Basin, Indonesia

Petrophysical water saturation methods is very important into reservoir characteristics because as water saturation decrease so oil saturation increase. The transition zone is very influential in the model of the reservoir volume in big area. Sometimes SCAL capillary pressure derived water saturation to be at fault because the plugs were not de-saturated to irreducible water saturation and capillary pressure equilibrium may not have been reached. This study focused in the Moza basin on West Java with interbedded shale and sand clastic sedimentary resevoir. Water saturation calculated above free water level using Cuddy’s method to ignore the value of the capillary pressure on the SCAL.

The methods have performed by calculating water saturation in the transition zone and ignored SCAL value. Cuddy’s saturation height method computed by porosity, height transition zone above free water level (h), and constant value (a and b). Porosity have gotten from petrophysical data obtained from density and neutron log then calculate height above free water level in the transition zone oil or gas. The results obtained in the form of Cuddy’s water saturation in the transition zone by considering the presence of reservoir sands capillary pressure in the transition zone of Moza basin. Cuddy’s water saturation compared with water saturation from log data using SCAL value. Water saturation from cuddy’s equation as good quality as water saturation from logging with SCAL data. Because that we can use this methods if we dont have SCAL with invalid data to compute water saturation in the transition zone.

Keywords :  petrophysical,model, saturation, cuddy, capillary, transition