Assessment of Natural Gas Resource Potential in Oil and Gas Geological Formations: An Overview of Selected Niger Delta Oil and Gas Field

Abstract

The Obagi OML 58 oil and gas field, located in the Niger Delta Basin, represents a significant source of hydrocarbon resources with considerable natural gas reserves. This study presents a comprehensive assessment of natural gas resources within the geological formations of the Obagi OML 58 fields, focusing on the evaluation of gas volume, reservoir characteristics, and production potential. Through advanced reservoir modelling techniques, including volumetric and decline curve analysis, this study examines the Original Gas in Place (OGIP) and production forecasts, incorporating reservoir dynamics such as pressure depletion and gas cycling strategies. An economic analysis of gas production was conducted with a baseline gas price of $5 per MMBtu, modelling both the daily and cumulative revenue from gas sales over time. The results indicate that the initial gas production generates a daily revenue of approximately $500,000 at the beginning of the year, based on a production rate of 100 MMscf/day. However, owing to the natural decline in production over time, the daily revenue decreases to approximately $111,500 by the end of the first year, reflecting the typical decline curve observed in gas fields. The cumulative revenue for the year totals approximately $50 million, with a slowing rate of revenue increase as production decreases. The application of gas injection strategies helps mitigate the decline and extend production, ultimately increasing OGIP and recoverable reserves. Economic modelling demonstrates that maintaining production through enhanced recovery techniques such as gas cycling can optimize long-term revenue, ensuring that the field remains economically viable. Our findings underscore the critical role of gas injection in maintaining pressure and maximizing long-term recoverable reserves, providing valuable insights for the sustainable development and economic optimization of the Obagi OML 58 fields. This study offers a framework for similar gas field assessments within the Niger Delta Basin, addressing both the technical and economic factors that influence the viability of gas production.