Enhanced Oil Recovery Practices: Global Trend, Nigeria’s Present Status, Prospects and Challenges

Abstract

Enhanced oil recovery (EOR) techniques are considered due to unimpressive oil recovery, limited oil reserves, and non-applicability of primary recovery methods in some (heavy oil) fields. In Nigeria, preparation is in gear towards implementing EOR projects. This paper therefore reviews the global trend of EOR practices and discusses Nigeria’s present status, prospects, and challenges. Most EOR projects are employed in sandstone (high permeability) reservoirs; hence based on lithological considerations, all EOR methods are feasible in Nigeria. However, miscible hydrocarbon gas injection is found to be a very good EOR choice because it would drastically reduce the uneconomical practice of gas flaring; besides, transportation of carbon dioxide (CO2) and flue gas is virtually non-existent in Nigeria. Chemical (especially surfactant) flooding is costly; hence it would be feasible in Nigeria if oil price is high. At present, cost implications of heat treatment facilities may be an impedance to implementing thermal EOR for heavy oil in Nigeria. Though microbial EOR is the cheapest, it is not favorable in high temperature (above 85 oC), high salinity (above 100,000 ppm) and deeper (beyond 3,500m) reservoirs. For EOR practices to thrive in Nigeria, there should be an extensive economic evaluation and forecasting, effective research and development, effective training of technical staff for proper operation, surveillance and maintenance of EOR projects, implementation of health, safety and environmental (HSE) guidelines, low inflation rates, low interest rates on loans, general price stability, favorable tax policy, low import duties on machineries and equipment used for EOR, modified private market decisions and encouraging legal and regulatory framework.