INTEGRATION OF SEISMIC ATTRIBUTTE AND SEDIMENTATION CONCEPT FOR PALEOGEOGRAPHIC AND SAND DISTRIBUTION MODELING IN SENG-SEGAT FIELD, BENTU BLOCK, CENTRAL SUMATRA BASIN.

摘要

Reservoir occurrences and distribution drive strategy and development concepts for oil and gas fields. Therefore, it is important to identify the distribution of reservoir zones. For the B-6 and B-5 sand reservoirs in the Seng-Seat Field, Bentu Block, this was achieved with paleo-geographic and sand distribution modeling. The outputs of the study were depositional environment and sedimentation patterns, which were used to build the B-5 and B-6 sand geometry and distribution model. The Binio Formation is the main biogenic gas reservoir in the Bentu area, and the B-5 and B-6 sands are the main reservoirs. Regionally, the Binio Formation was deposited in a transitional coastal environment. Data available for this study are wire-line logs, 2D seismic data (attribute and coherence), and pressure survey data. The preliminary model was built based on amplitude attribute, because gas bearing zone creates bright-spots on the seismic image. Then inversion and instantaneous frequency methods were applied to identify B-5 and B-6 distribution and heterogeneity. Finally, integration of the sand distribution map, controlled with the seismic inversion boundary, the previous study of regional depositional environment, and sand-shale ratio analysis, allowed the creation of a detailed paleogeographic and sand distribution model of the B-5 and B-6 reservoirs. The models for the B-5 and B-6 reservoirs show different sedimentation patterns and sand distribution, including sand bars, tidal inlets and tidal flats. Better understanding of B-5 and B-6 reservoir heterogeneity will lead to a better estimation of hydrocarbon volumes, and therefore a fit-for- purpose field development scenario for the Seng- Segat field.