RESERVOIR SANDSTONE CHARACTERIZATION USING TRIGONOMETRIC APPROACH TO CURVED PSEUDO ELASTIC IMPEDANCE (CPEI) AND PSEUDO DENSITY ATTRIBUTES IN THE ROABIBA FORMATION, “XYZ” FIELD, BINTUNI BASIN

• Main Author: Rahadatul 'Aisyi, Ziqni
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/86259
• Institution: Institut Teknologi Bandung

This study focuses on the “XYZ” Field in the Bintuni Basin, specifically the Roabiba Formation which is a Jurassic age sandstone reservoir with significant hydrocarbon production in Eastern Indonesia. The Roabiba Formation is located in a very deep location with intensive structure and high relief and has a tendency to have low porosity values due to the tight sand lithology. Based on elasticity parameter analysis, MuRho and VpVs Ratio are sensitive parameters in separating lithology and fluid in this field. For further analysis, the Extended Elastic Impedamce (EEI) method with Linear Programming Sparse Spike (LPSS) inversion is used to produce a more accurate elastic parameter model with high resolution so that it will be more detailed in separating sand and shale and can predict fluid and lithology distribution. The volume VpVs Ratio obtained from the Extended Elastic Impedance (EEI) method has a higher correlation of 0.814 compared to the VpVs Ratio from AI/SI with a correlation of 0.597, so the EEI method is more effective for estimating the log VpVs Ratio. Since the variation of EEI angle (?) produces a linear curve trend, while the RPTs wet sandstones have a nonlinear trend, the concept of Curved Pseudo Elastic Impedance (CPEI) is used to analyze the fluid distribution through SW volume transformation with a correlation of 0.813. However, despite the high correlation, in this study the CPEI method is less effective in describing the fluid distribution. This is due to the poor far seismic amplitude, as the layer is at a considerable depth, so the seismic waves lose energy when passing through various overlying lithologies. In addition, the Pseudo Density attribute is also used which can analyze the distribution of lithology through porosity volume transformation. The analysis results show low VpVs Ratio, density, and water saturation values as well as high MuRho and porosity values. This indicates that in the “XYZ” field, the Roabiba Formation is a tight sandstone reservoir and is indicated to contain hydrocarbon fluids.