Sequence stratigraphy of the foraminiferal zones F9700 and F9800 in the Niger Delta: A comprehensive litho-sequence approach

Abstract

Understanding how variations in relative sea level affect reservoir structure requires a thorough understanding of sequence stratigraphy. A detailed sequence stratigraphic investigation was performed on the OML X field to uncover and establish links between concurrently originating hydrocarbon reservoir deposits. The analysis of major stratigraphic surfaces, such as maximum flooding surfaces and sequence borders, was made possible by the integration of well log and biostratigraphic data. The research region includes two palynological subzones, P850 and P860, discovered in the foraminifera zones F9700 (Haplophragmoides 24) and F9800 (Bolivina 46). The study discovered two distinct chronological limitations, which occurred approximately 6.7 million years ago (Ma) and 5.6 Ma, respectively. Furthermore, two maximum flooding surface events were discovered, estimated to have happened at 6.0 Ma and 5.0 Ma. When well log and biostratigraphic data were combined, it was simpler to identify sequences 1, 2, and 3, which correspond to the LST, TST, and HST. The implementation of this detailed methodology facilitated the identification and linking of hydrocarbon sources inside the high- and low-stand system tracts. The findings of the study demonstrated a good link between well-logged log data and biostratigraphy utilizing well-accepted primary stratigraphic surfaces and depositional histories. Furthermore, using fault interpretation and correlation approaches has enhanced our understanding of reservoir geometry and continuity in the field, making it easier to discover potential reservoirs.