Biogenic Gas Reservoir Distribution Analysis Using AI Inversion and Seismic Attributes in The Nias Basin, North Sumatra

Abstract

Biogenic gas research in Nias and the surrounding area was performed using AI inversion and seismic attributes. The seismic data was acquired using Geomarine III for multi-channel seismic with a track length of 1740 km. Reservoir characterization was carried out to obtain the physical parameters of rocks affected by fluid and lithology. In the study area, there are hydrocarbon prospects in limestone lithology with a depth of around 1562 meters. Based on the results of sensitivity analysis, the cross plot between acoustic impedance and NPHI was sensitive in separating reservoir rock. The targeted reservoir in the limestone has physical characteristics of acoustic impedance values between 20,000 - 49,000 ((ft / s) * (g / cc)) and NPHI values in the range of 5% - 43%. The cross plot between the acoustic impedance and resistivity can separate the fluid-containing rocks with resistivity values in the range of 5 - 43 ohm-m. The results of acoustic impedance inversion using model-based methods show the potential for hydrocarbons in the "Singkel" well with acoustic impedance in the range 22938-277815 ((ft / s) * (g / cc)).