Water Balance Assessment for Water Management in Oil & Gas Operations: A Methodological Approach

Abstract

The Water Balance Assessment is a methodological approach developed and applied by Eni for the identification of improvements in water management at site level. The approach is based on three steps. The following report describes each step and the application of the approach to a real case study in Tunisia. Water is a vital resource for our planet and for humankind. Biodiversity and ecosystems’ preservation, human health, and food security as well as energy production, industrial development and economic growth are all dependent on water. The consequences of climate change and the actual projections of increasing water demand will affect water availability and quality in the coming years. About the Oil & Gas sector, this industry consumes and produces significant volumes of water. For this reason, energy companies must consider sustainable options for the use of this resource, especially in water stress areas. This can be achieved through:A deep knowledge of the site water streams and of the context where the site is located.Identification of improvements and initiatives that could reduce the water risk of the site. About water safeguarding, Eni is committed to pursue the following practices:Water Conservation: Upstream Oil & Gas operations need significant quantities of water; a key element for its conservation includes the reduction of withdrawals and the efficiency in water use.Water Reuse and Valorization: Upstream Oil & Gas operations must manage large volumes of wastewater, mainly Produced Water. Design solutions shall introduce and maximize the recycle of water with the adoption of suitable treatments, to make discharges compatible with the reuse in the same production cycle or by third parties (e.g., other plants, local communities), and pursue the opportunity to reuse industrial water, instead of discharging it as wastewater. For their deployment, Eni has defined and applied a methodological approach to support the definition of improvement and optimization initiatives of water management at the site level. The approach represents an application of a "convergence approach" which, starting from an overall view of the site, identifies opportunities, further and more detailed areas of analysis, and design projects that can improve water use, management, and reuse. The methodological approach is based on the following steps:A country-based framework study on water resources, and water-related risks analysis at country and local level.A Water Balance Assessment, gathering water qualitative and quantitative information and site framework details.Definition of site initiatives for wastewater reuse and valorization, and for the optimization of water withdrawals, based on the above steps and considering local legislation. Through this approach, operational water risks exposure is analyzed in detail, allowing to address a wide range of opportunities for the improvement of water management, also through the development of new synergies with local communities.