RESERVOIR CHARACTERIZATION IN “OGF” FIELD WEST NATUNA BASIN USING EXTENDED ELASTIC IMPEDANCE INVERSION AND MULTIATTRIBUTES ANALYSIS

• Main Author: GITA FREDERICA NIM: 12314053, OLIVIA
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/29880
• Institution: Institut Teknologi Bandung

<p algin="justify">The "OGF" field in the West Natuna Basin is a hydrocarbon producer field, especially in the Udang Formation. This formation consists of porous sandstone and intercalated sandstone and shale. The research target is a thin sandstone layer in the Udang Formation so that a method is needed to characterize this sandstone reservoir. To characterize the reservoir, elastic rock parameters that are sensitive to changes in lithology and areas with good porosity are needed. Then, sensitive parameters will be applied to the seismic area and it requires an equivalent reflectivity value of the parameters that can be obtained using Extended Elastic Impedance (EEI) method.<p algin="justify"> <br /> <p algin="justify">The parameter SQp and SQs are used in this research. The SQp is linear to gamma ray logs so it is sensitive to distinguish sandstone from shale, represented by EEI (-90°) and the SQs is linear to porosity logs and it is sensitive to identify areas with good porosity and the chance to be filled with hydrocarbons, represented by EEI (-9°). Then model based seismic inversion is used to determine the distribution of good porosity sandstones. Afterwards, the inversion results of each well are averaged and used as input to the multiattribute analysis to improve the dynamic range of seismic inversion results.<p algin="justify"> <br /> <p algin="justify">In this research, iterative multiattribute analysis has been proven to improve the quality of seismic inversion results and from that, the SQp cut-off is below 0,5 for sandstone and SQs is above 0,55 for good porosity sandstone. Potential good porosity sandstone zones are in the southwest of the SN-3 well, especially at the Udang-3 and Udang-4 horizons (zone D) which are associated with high areas and fault zones.<p algin="justify">