Sequence stratigraphy and structural analysis of the Emi field, offshore depobelt, eastern Niger Delta Basin, Nigeria

Abstract

3D seismic data, wireline logs from six wells, checkshot and biostratigraphic data were used to subdivide the stratigraphic section within the Emi Field, eastern   Niger Delta, into packages of sediments bounded by chronostratigraphically significant surfaces. The results revealed two sequence boundaries and three  aximum flooding surfaces, which subdivided the stratigraphic succession within the Emi Field into three depositional sequences. Highstand system tract and transgressive  system tract were identified within the depositional sequences. Marker shales, characterized by index fossils Haplophramoides-24 and Bolivina-46, were used to  date the key bounding surfaces with the aid of the Niger Delta chronostratigraphic chart. Ages assigned to the sequence boundaries were 5.6 Ma and 4.1 Ma. Based  on log motifs and biostratigraphic data, the siliciclastic successions penetrated by wells within the Emi Field were inferred to be deposited in a neritic    paleoenvironment. Two major faults, F1 and F3, ran across the study area and closures considered as good hydrocarbon prospects were identified and delineated.  Analysis of horizons within the sequences and individual system tract revealed that hydrocarbon was hosted both in the transgressive systems tract and highstand  systems tract.