Application of Hydraulic Flow Unit (HFU) and Windland R35 Methods in Sand-5 Reservoir, Field ‘S’, Talang Akar Formation, Asri Basin, Indonesia

Abstract

The Sand-5 Reservoir in the Talang Akar Formation is the main oil and gas producer in the Field ‘S’, Asri Basin, Indonesia. Reservoir rock type (RRT) can be applied to optimize the performance of this reservoir. This study aims to compare the RRT methods between Hydraulic Flow Unit (HFU) and Windland R35 to find the best RRT method. Both methods utilized the porosity and permeability to classify the number of RRT, subsequently validated by the regression value (R2) of core permeability with predicted permeability. Four RRT values have been identified for both methods that are RRT-1 represent the very good reservoir quality, RRT-2 represents the good reservoir quality, RRT-3 represents the moderate reservoir quality and also RRT-4 represents the poor reservoir quality. The numbers of porosity and permeability for HFU method is 32-40% and 19.3-29.4 Darcy (RRT-1); 31-39% and 5.3-18.3 Darcy (RRT-2); 20-36% and 0.4-6.8 Darcy (RRT-3); 15-34% and 0.01-0.4 Darcy (RRT-4), while for Windland R35 method is 31-40% and 7.7-29.4 Darcy (RRT-1); 30-39% and 4-10 Darcy (RRT-2); 24-38% and 0.2-6.8 Darcy (RRT-3); 15-33% and 0.01-0.2 Darcy (RRT-4). Based on the relationship between core permeability and predicted permeability from each RRT, the result of the Winland R35 method is better than the HFU method.