Managing offshore drill cuttings waste for improved sustainability

Drill cuttings are an important waste from drilling operations due to the generated volume and the potential for environmental impacts. Alternatives for treatment and final disposal of these residues are available, with performance differing in multiple aspects, each impacting overall sustainability of existing technologies. Although procedures for comparing sustainability of processes are not new, for end-of-pipe technologies the common approach in the literature is the use of indicators that express the benefit of adding a waste management step. In this scenario, the work presents a methodology for sustainability analysis of solid waste management, adapted to specificities of drill cuttings, illustrated by a case study in the offshore Brazilian pre-salt area. Performance of a given technology is evaluated by integrating environmental, economic, safety and technical aspects in an original multi-criteria analysis. The evaluated waste management technologies are: offshore discharge, onshore disposal, offshore cuttings re-injection and microwave treatment followed by onshore disposal. Process inventories are compiled and support calculation of the proposed Sustainability Degree index for ranking of alternatives, which points to offshore discharge as the most sustainable among the evaluated technologies, followed by Microwave Treatment, Onshore Disposal and Offshore Re-injection. The methodology can indicate opportunities for technical optimization and contribute to the decision-making process on drilling waste management. (C) 2017 Elsevier Ltd. All rights reserved.