Integrated Petrophysical Evaluation and Reservoir Characterization of the Zarama Field, Offshore Niger Delta using Multi-Well Geophysical Log Analysis

Abstract

The paper will provide a detailed petrophysical study of the Zarama field in the Niger Delta, based on wireline logs from five wells. Porosity, permeability, shale content, and fluid saturations are the primary reservoir parameters in the study, used to analyse reservoir quality, heterogeneity, and producibility. Porosity is good to excellent (20-32 per cent), declining with depth in response to compaction, and quite diverse (7-781 mD), primarily determined by shale volume, not by its porosity. Reservoir thickness ranges from 6 m to more than 700 m, and lateral continuity has been found in the massive sands such as S1, S3, S14, and S16, which contain large hydrocarbon pore volumes and have high production potential. The solution of fluid contacts (gas-water, gas-oil, oil-water) was possible even in the absence of a density log anomaly due to the presence of gases. The field is rather gas-bearing, with minor quantities of oil and condensate. It thus has an estimated recoverable reserve of 2.85 million barrels of oil equivalent and 5.85 billion cubic feet of gas. Multi-well and multi-reservoir system petrophysical interwell correlations show no clear stratigraphic trap system, and these demands require integrated multi-well, multi-reservoir system interpretation to obtain adequate characterisation of the reservoir and development planning. All in all, the research indicates that integrated log interpretation improves dataset reliability, optimises petrophysical parameters with high confidence, and provides a robust framework for future exploration and development in this complex offshore deltaic setting.