Exploration of the environmental implications of ageing conventional oil reserves with relational analysis

A novel method based on relational analysis is presented for assessing the performance of conventional oil exploitation and its environmental implications, with a focus on the energy-water nexus. It considers the energy system as a metabolic network and integrates various factors relevant for technical, economic and environmental processes, thus avoiding some of the simplifications inherent in conventional approaches to the assessment of primary resource quality, such as economic cost-benefit analysis (CBA) and the energy return on investment (EROI). Relational analysis distinguishes between functional (notional) and structural (tangible) elements in the metabolic network, which allows a simultaneous characterization and geo-localization of the exploitation process across different scales and dimensions of analysis. Key aspects of the approach are illustrated with data from the Ecuadorian oil sector spanning the period 1972–2018. It is shown that by establishing a relation among the characteristics of the exploited oil fields (oil typology, age of field) and those of the exploitation process (requirement of energy carriers, labor, freshwater and power capacity and generation of greenhouse gases and oil-produced water), changes in the performance and environmental implications of the oil extraction system can be characterized at different points in space and time.