Perpustakaan Digital ITB

Identifying productive zones in low resistivity reservoirs remains a major challenge in formation evaluation, as they are often misinterpreted as water zones due to their low resistivity values. This study presents a petrophysical characterization of a low resistivity reservoir in Well C-107 across 12 ft target interval, where the average formation resistivity was only 3.84 ohm.m, despite the well proving to be productive for hydrocarbons. Multimineral analysis using Mineral Solver revealed the presence of glauconite (3.4%) and clay (2.1%), which triggered excess conductivity and microporosity phenomena, thereby suppressing resistivity values. Water saturation evaluation involved comparing five methods such as Archie, Indonesia, Simandoux, Waxman-Smits, and the Waxman-Smits normalization (Juhasz) method, revealing that the Archie method yielded the most pessimistic results, while the Waxman-Smits method yielded the most optimistic. The Juhasz method, with a water saturation value of 0.4425, was selected as the most representative solution because it showed the smallest deviation from the breakthrough threshold on the fractional flow curve. This study demonstrates that employing the appropriate saturation model and integrating mineralogical data are crucial for uncovering reservoir potential hidden by low resistivity.