Reservoir Characterization Using Seismic Attributes In W-Field, Onshore Niger Delta

Seismic attributes are very useful tools for reservoir characterization and prospect evaluation because they enhance visibility of features that are below the resolution of seismic data. This study utilized seismic attributes such as maximum amplitude, root mean square (RMS), average energy and sweetness for prospect, identification and evaluation in W-Field, onshore Niger Delta using seismic and well data. Three reservoirs were identified (A, B, C) and reservoir C was selected after thorough scrutiny of available well logs, sand thickness and hydrocarbon presence. Faults were enhanced using variance attribute and the result shows that closures on reservoir C surface are associated with collapsed crestal structures bounded by major faults responsible for hydrocarbon trap formation. The RMS and maximum amplitude attribute results shows the higher the RMS value, the brighter the amplitude anomalies, which coincide with the distribution of hydrocarbons in the reservoir and supported by Average energy interpretations. However, the anomalies are brighter and sharper using the Average energy seismic attribute. The result shows moderate to high sweetness zone (sweet spots) reveals bright amplitude anomalies within the zone of interest, indicating high amplitudes and low frequency of hydrocarbon bearing sand zone. Similarly, multitrace coblending (sweetness + variance) conducted on seismic volumes reveals that there is no significant difference in structure and bright amplitude anomalies with those recognized using the surface attributes. Seismic attributes offer complimentary tools to qualitatively and quantitatively characterize stratigraphic and structural features in a field, especially those features below the resolution of seismic data.