Publications

Geomodeling the South Belut gas field for the Arang and Udang Formation presents unique challenges to figure out the appropriate seismic attribute primarily due to the presence of gas in the reservoir. The challenge lies in generating the seismic attribute that best represents the underlying stratigraphical patterns, enabling accurate reservoir characterization. Additionally, the petrophysical complexities stem from the occurrence of cool shale, rendering the conventional gamma-ray log insufficient for VSh (volume of shale) calculations. This study presents a comprehensive methodology to address these challenges.

To overcome the gas-induced response in seismic data, extensive analysis of multiple seismic attributes was conducted. The ultra-far-angle seismic stack was identified as the most indicative of stratigraphical patterns, revealing the complex channel system within the formation. A customized methodology was developed to normalize the properties and effectively remove the gas effect, resulting in highly detailed geologic features of the South Belut gas field.

In petrophysics, the challenge of cool shale was addressed by combining gamma-ray logs with neutron density measurements. The resulting volume of shale (VSh) calculations were refined through a calibration of cutting data. Petrophysical data integration using gamma-ray and neutron density logs, calibrated with cutting data, enhanced rock typing. Cluster analysis and cut-off sensitivity further improved rock typing alignment.

By identifying the most informative seismic attribute and implementing an innovative approach for petrophysical analysis, including cluster analysis and cut-off sensitivity for rock typing, a comprehensive understanding of the subsurface characterization was achieved. This study successfully addressed the challenges posed by gas in the geomodeling of the South Belut Arang formation, leading to a better development strategy for the field.