SEISMIC ANALYSIS OF THE TRANSGRESSIVE SYSTEMS TRACTS (TSTS) OF THE NIGER DELTA

Abstract

One way of identifying our MFSs is to look out for shale tops of high acoustic properties within a shale interval that corresponds to the lowest resistivity values and widest separation between neutron and density values. The TSTs culminate to a MFS as it comprises the deposits accumulated from the onset of coastal transgression until the time of maximum transgression of the coast, just prior to renewed regression (SepmStrata, 20). The seismic character of the shales within these TSTs could vary factoring the effect of depth trends, hence a need to understand the trend with increasing depth and thereby increased compaction. From generated synthetic, using the seismic responses at interfaces within the lithologies cut across by one of our HP well in the Central Swamp depobelt, a study integrating Reflectivity Pattern Analysis (RPA) and Sequence Stratigraphic analysis was carried out to understand the behavior of our shales within the TSTs. Key bounding surfaces which subdivide the strata into contemporaneously deposited sediment packages were identified from well log responses from a complete suite of logs which included Gamma Ray, Resistivity and Porosity logs. It was observed that shales in the TSTs were of higher acoustic properties compared to sales in the HSTs.

Keywords

• Reflectivity
• Seismic Analysis
• Transgressive Systems Tract