Publications

Permeability is a necessary parameter in the analysis of a reservoir yet to predict permeability is quite a complex task. Core data from wells at Bunyu Field show that porosity has a low correlation with permeability. The uncertainty of permeability prediction by the porosity-permeability relationship leads to the usage of the rock typing method in this field. The rock typing method classifies rock types based on core data that provide variation in pore geometry. The Hydraulic Flow Units (HFU) rock typing method is expected to enhance permeability prediction by determining rock type (RT) based on pore geometry, normalized porosity (_z), and Reservoir Quality Index (RQI). HFU rock typing analysis was carried out on four wells and 38 Routine Core Analysis (RCAL) data samples distributed across three formations, Bunyu, Tarakan, and Santul. The HFU rock typing analysis results delivered four rock types, namely RT-1, RT-2, RT-3, and RT-4, which were classified based on the Flow Zone Indicator (FZI) value. Each rock type exhibited a better correlation between porosity-permeability, and each correlation was used to predict the permeability based on the rock types. Predicted permeability based on rock type HFU produced a high correlation coefficient of 0.84, an improvement compared to the predicted permeability based on the conventional Timur method which has correlation coefficient 0.27. The permeability prediction method using HFU rock typing analysis enhances the permeability prediction results. Rock type RT-2, distributed primarily at Santul Formation, is shown to be an appropriate rock type in trasmitting fluids having the highest permeability value among the other RTs.