The Study of Reservoir Distribution Within the Stratigraphic Traps Using Seismic Attributes, Central Pattani Basin, Gulf of Thailand

Abstract

The study of reservoir distribution within stratigraphic traps is necessary to open up hydrocarbon resources and add more opportunity in hydrocarbon discovery. The study area is a mature exploration and development area where most of the structural traps have been tested and relevant hydrocarbon resources have been developed. In addition, the reservoir are dominantly thin-bed sands which are mainly undetectable using the original seismic volume. Therefore, this study integrates 3D seismic volumes, well log data, rock physics analysis, horizons interpretation and seismic attributes analysis to identify potential stratigraphic traps and improve the visualization of reservoir distribution. Crossplots analysis using ten well log data reveals that density, P-wave velocity and P-impedance can be used for lithology discrimination where sand has lower density and P-impedance as well as higher P-wave velocity compare to shale. Several seismic attributes including amplitude enhancement, edges detection and thin-bed detection were applied to the full-stacked and partial angle-stacked seismic volumes. The RMS amplitude extraction clearly imaged channelized features oriented in N-S direction and parallel to basement. The drilled well data proved that these chan-nelized features are associated with sands and hydrocarbons. Thus, the results indicate that the channel orientations and hydrocarbon traps are not influenced by basement and the seismic onlap onto basement does not always imply shoreline deposit. Moreover, the integration of imaged channels with known hydrocarbons at well locations and structural mapping can be used to identify reservoir distribution for predicting well locations. The high amplitude channelized features located within structural closures can identify stratigraphic traps forming lower risk exploration and development targets