RESERVOIR CHARACTERIZATION USING EXTENDED ELASTIC IMPEDANCE INVERSION OF UDANG FORMATION, “SZF” FIELD, WEST NATUNA BASIN

• Main Author: Zikril Fazillah, Said
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/68762
• Institution: Institut Teknologi Bandung

The West Natuna Basin is one of the basins that produce hydrocarbon, especially gas, in Indonesia. The “SZF” Field is located in the West Natuna Basin and focusing on Udang Formation. The Lithology of this formation is an interchange of thin-layered shale and sandstone, so it needs a method that can separate the two lithologies well. In assisting the characterization process, elastic parameter that are sensitive to the lithology and fluid distribution in the target area is needed. Therefore, this study utilise the Extended Elastic Impedance (EEI) inversion method because of its ability to create reflectivity volume of various elastic parameters. Based on the sensitivity analysis, it was found that the parameter that are sensitive to differentiate between reservoir that contain hydrocarbon and non-reservoir in the target area are the Lambda-Rho and Vp/Vs ratio. The multiplication between Lambda-Rho and Vp/Vs ratio is expected to enhance the parameter ability to differentiate reservoir that contain hydrocarbon and non-reservoir. Then the reflectivity volumes of P-wave (Rp) and S-Wave (Rs) is created using the two-term AVO Ursenbach-Stewart equation. From the volumes of Rp and Rs, the EEI reflectivity volume of sensitive parameters are formed using the EEI equation. Then the volume of sensitive parameters was inverted using the Linear Programming Sparse Spike method. The result of this study shows that the target zones are located in the Udang 1, Udang 2 and Udang 3 formation. The parameter that generated by the multiply of Lambda-Rho with Vp/Vs ratio are quite good in mapping the distribution of the hydrocarbon reservoir with the cutoff at 60 GPa*(g/cc). Hydrocarbon reservoir potential is located at the high areas of Udang 1, Udang 2 and Udang 3 Formation.