Seismic Attributes for Reservoir Characterization of a Field, Central Depobelt Sedimentary Basin of Niger Delta: A Qualitative Interpretation

Abstract

A seismic attribute is any measure of seismic data that helps us better visualize or quantify features of interpretation of interest. It could be described as a powerful aid to improve the accuracy of interpretations and predictions in hydrocarbon exploration and development. A qualitative seismic attributes analysis was carried out for the evaluation of subsurface geological features and hydrocarbon potential of an oil field in Niger Delta Basin. The Interpretation using geophysical software on the 3D seismic data presents a great opportunity for reservoir characterization, enhanced with attributes from seismic signal processing, complex seismic trace attributes, structural attributes, stratigraphic attributes and surface attributes. The seismic 3D cube data was investigated for potential structural and stratigraphic controls within the study area with surface attributes. Seismic attributes including reflection intensity, RMS amplitude, Time gain, Trace AGC, Sweetness, Envelope, Instantaneous Frequency, Instantaneous Phase, Quadrature amplitude, Ant tracking, Dip deviation, Gradient Magnitude, Local Structural dip, Chaos, Iso-Frequency, Local flatness were used for the interpretation of the 3D seismic cube, time and depth surface maps generated. The result shows moderate to high sweetness region (sweet spots) within the zone of interest, Envelope attribute results show acoustic impedance contrasts indicating discontinuities, lithology changes, possible presence of hydrocarbon (bright spots), Variance, Dip deviation, Gradient magnitude and Ant tracking attributes enhanced the signals to map out discontinuities caused by faults and fractures signature which enabled the delineation of the zone of interest. This study on the qualitative interpretation of seismic attribute validates the lithology discrimination using elastic rock properties from well logs and shows the effectiveness of the use of seismic attributes for the optimizing, understanding, improving, identifying, and unmasking hidden features of the reservoirs in the field. For successful exploration and production of hydrocarbons, it is imperative to characterize the hydrocarbon reservoir accurately in terms of its fluid properties and lithology using attributes extracted from seismic.