Öl- und Gasforschung

Abstrakt

A Case Study of Carbonate Deposition and Deformation in the Greater Ughelli Depobelt, Niger Delta, Nigeria

Izuchukwu I Obiadi

The growth and development of structural and depositional systems in the hydrocarbon-rich Niger Delta off Nigeria's Atlantic coast, West Africa, involves a complex interaction of extension, contraction, and subsidence, with up-dip extensional systems kinematically linked to down-dip contractional systems via a transitional zone at any given point in time. Local structural and depositional systems connected with individual extensional faults and thrust-cored folds, local subsidence and withdrawal associated with shale diapir formation are all shown on the regional tectonostratigraphic zonation. The study focuses on growing faults and accompanying deltaic sedimentation in the Niger Delta's Greater Ughelli Depobelt. A regional sequence stratigraphic framework of the study was developed using 3D seismic, a variety of well log suites, and biostratigraphic data, study area was produced. Six Flooding Surfaces at Maximum Levels Within the constraints of available data, MFSs and five Sequence Boundaries SBs were identified. A structural interpretation model and framework for the research area was also developed using these regional horizons/ markers (MFSs and SBs) and the events pattern in the seismic volume. Fault activity began well before 31.3 Ma and extended well beyond 20.7 Ma, according to structural study, and has had a significant impact on the development of accommodation space and sediment buildup. Stratigraphic thickness has increased in the basin ward direction as a result of structural deformation and structurally driven accommodation creation, and 'local depocenter' has migrated to the NW at various periods in the structural development of the study area and then to the SE resulting also in lateral changes in stratigraphic thicknesses in these directions.