International Journal of Scientific Research and Engineering Development-– Volume 3 Issue 3, May – June 2020 Available at www.ijsred.com ISSN : 2581-7175 ©IJSRED: All Rights are Reserved Page 735 Sequence Stratigraphy and Petrophysical Evaluations of the Miocene Sediments in the Eastern Niger Delta Basin, Nigeria *Fortune I. Chiazor and **Charles U. Ugwueze *Department of Geology, University of Port Harcourt, Nigeria. *Email: fortune.chiazor@uniport.edu.ng **Department of Geology, University of Port Harcourt, Nigeria. **Charles.ugwueze@uniport.edu.ng Abstract Miocene sediments from nine oil wells in the Eastern Niger Delta basin were subjected to both stratigraphic sequence analysis and petrophysical evaluation, which established a good relationship among reservoir properties with various depositional sequences. Three sequence boundaries (SB 8.5Ma, SB 10.35Ma and SB 10.6Ma) and three maximum flooding surfaces (MFS 9.5Ma, MFS 10.4Ma and MFS 11.5Ma) were important stratigraphic surfaces established within the field. These surfaces cut across various depositional settings from fluvial proximal marine to shoreface environments. Reservoir sand-A was interpreted as a channel sand within the fluvial setting and showed good reservoir properties with average net-to-gross ratio of 0.9, average porosity value of 19.23% and average permeability value of 540mD. Reservoir sands-B, C and E were interpreted as shoreface sands with good to excellent reservoir properties with average net-to-gross ratio ranging from 0.8 to 0.98, average porosity values ranging from 9.2 to 23% and average permeability values ranging from 189 to 996mD. At the top of the stratigraphic sequence was a transgressive shale sequence, which probably formed an excellent seal facies that perhaps trapped the observed hydrocarbon occurrence in the area. Key words: Sequence Stratigraphy, Petrophysical Evaluation, Depositional Environments, Reservoir Sand and Miocene Niger Delta Introduction Petroleum production from conventional reservoirs is on the decline globally. Exploration and Production companies are now developing complex reserves by focusing on the microscopic pore spaces of reservoirs that are filled with hydrocarbon. Thus, the need to relate the reservoir properties to high resolution sequence stratigraphic analysis to make a detailed predictions of specific intervals with optimum reservoir connectivity, distribution and stratigraphic trapping potential (Lang et al, 2002). Physical evaluation of reservoir properties is one of the most useful and important technique that helps define physical rock characteristics such as lithology, porosity, permeability that is used to identify productive zones, thickness and depths to hydrocarbon zones and estimate hydrocarbon reserves. (Asquith and Gibson, 1997). RESEARCH ARTICLE OPEN ACCESS