Monitoring of Drilling Fluids and Cuttings as an Environmental Management Tool for Offshore Fluid Operations

Abstract

Abstract This study aims to present the comprehensive outcomes of drilling fluids and cuttings monitoring conducted in the Santos Basin, Brazil, during drilling operations. The research sheds light on the environmental implications and management strategies related to offshore drilling activities. These insights can support decisions guided by Life Cycle Assessment (LCA), aiding in informed choices to enhance efficiency and sustainability. The drilling fluids and cuttings monitoring project (DFCMP) encompasses data on drilling discharged into the sea. The monitoring took place during the drilling of 41 deep water wells in Santos Basin, Brazil. Samples were collected at various stages of drilling operations. Data includes discharge quantities, ecotoxicological profiles of the fluids, as well as determinations of metals and polycyclic aromatic hydrocarbons (PAHs) in the samples. These methods enabled the evaluation of environmental impacts throughout the drilling lifecycle. This comprehensive approach provides valuable insights into the effects of drilling activities, contributing to informed decision-making in line with Life Cycle Assessment principles. The monitoring of fluids and cuttings discharged into the sea from 41 drilling operations carried out between 2022 and 2023 in the Santos Basin, Brazil, generated representative samples of fluids and cuttings. These samples account for the offshore discharge of 16000 m³ of cuttings and apporximately142000 m³ of aqueous fluids. Chemical and ecotoxicological analyses conducted on these samples confirm the environmental compliance and quality of these discharges, affirming their adherence to the legal requirements established in Brazil. Regarding the waste generated for onshore disposal, the compiled results indicate an average annual generation of around1590 tonnes of waste, with about 56 % comprising liquid waste from fluid operations, primarily aqueous fluids. Despite fluid and cuttings characterization being present in scientific literature, few contributions emphasize samples collected prior to sea discharge. Many characterizations focus on terrestrial disposal routes and cater to relevant criteria for this purpose. Our study's findings enhance understanding of qualified fluid and cuttings discharged at sea, highlighting industry best practices that meet Brazilian regulations. These locally relevant data are crucial for life cycle analysis, aiding environmental profiles and impact assessment for different waste management routes.