Publications

The main reservoir in the “X” Field is a steep-flanked isolated carbonate build-up and consists of complex heterogenic characters. The complexity of the carbonate reservoir results in huge obstacles to understand the reservoir characteristics. In order to understand these reservoir characteristics, Petrophysical Rock Type (PRT) analysis was conducted. The Pore Geometry Structure (PGS) method is chosen for determining the PRT in this field. The PGS method uses porosity geometry and pore structure as the parameters for correlating the relationship between grain sizes, pore geometry, pore throat and capillary pressure (Pc). The data is derived from Routine Core Analysis (RCAL), Special Core Analysis (SCAL) and thin section compiled with Open Hole Log data from two exploration wells. The research gives the results that the reservoir is divided into six Petrophysical Rock Types. PRT-6 has the poorest porosity and permeability and the thin section samples have shown very poor visible porosity with sparry calcite and saddle dolomite have filled almost all the porous space. Based on thin section analysis and SCAL test, PRT-1 has the best porosity and permeability compare to other Rock Types. It has good-visible porosity with abundant of moldic and vuggy porosity as its dominant secondary porosity. Porosity and water saturation (Sw) were used as key parameter inputs for the PRT equation. PRT and permeability equations from the PGS method show that constantly increasing and the power of porosity decreasing from the best (PRT-1) to the worst (PRT-6). However, there is a limitation in applying the PGS method, which it cannot be applied in water saturated zones. Every zones that have high Sw would be determined as bad PRT even though some zones show good visible porosity in thin section. Further study and investigation are needed to solve this limitation.