Sequence stratigraphic framework of ‘AKOS’ field, Niger Delta

Abstract

The aim of this study is to investigate the sequence-stratigraphic framework of a hydrocarbon prospect of ‘AKOS’ Field, Niger Delta, using well logs, and 3-D seismic data. To achieve this, the researchers identify the various sand/shale and seismic facies, build a sequencestratigraphic framework of the oilfield, and assess the petroleum play of identified system tracts. A fault analysis reveal twelve (12) fault sets (Fault 1-12) mapped across the seismic volume. These faults are picked on an increment of 50 and examined for consistency using time slice and variance attributes. Faults-1 and 2 are major faults. The other ten (10) are minor faults. The mapped faults are normal growth faults common in the Niger Delta, as most trend approximately E-W direction. Sequence-stratigraphic analysis of the prospect based on chronostratigraphic correlation reveal two (2) sequences. Sequence-1 is between Sequence Boundary (SB) 0 to SB-1. Sequence-2 is between SB-1 to SB-2. Results from interpreted and analyzed system tracts reveal all three (3) present in Sequence-1. However, the Lowstand System Tract (LST) is absent in Sequence-2. The Lowstand Systems Tracts (LST) identified by shallowing and coarsening-upward succession, and progradational and aggradational parasequence sets are major hydrocarbon-producing intervals within the oilfield. The Transgressive Systems Tract (TST) typified by dirtying-upward seal the Lowstand Reservoirs. The upper section of the Highstand Systems Tracts (HST) has reservoir potential.