Establishing a regulation for the use and discharge of drilling and completion fluids in Brazil has been a challenge. The lack of specific procedures and limits for some of the environmental control parameters has been generating difficulties for the final approval of these fluids, requiring additional efforts and provoking discussions between the oil companies, suppliers and the Brazilian environmental authority.One of the most relevant control parameters required for the use and discharge of fluids in the environmental permitting processes is the evaluation of acute and chronic toxicity on marine organisms. Even though the limit required for acute toxicity using the mysid shrimp Mysidopsis juniae is well defined (96-hr LC 50 >30,000 ppm of SPP), there is not a limit established for the chronic toxicity using the larval stages of the sea-urchin Lytechinus variegatus, making the acute value the only established parameter used to define the approval of the fluids. Therefore, although chronic results are being generated for several fluid formulations, due to the lack of a specific limit, no direct use is being made of these results.The main purpose of this work is to contribute to the knowledge and proper use of toxicity results by comparing the values obtained for acute and chronic tests. For this evaluation, results obtained for different types of drilling and completion fluids will be used, both aqueous fluids (AF) and non-aqueous fluids (NAF). The results were analyzed by statistical tools to determine if a correlation between the two types of toxicity assays is feasible, considering the type of fluid evaluated.

This paper will discuss a mobile effluent treatment system, which was developed in Norway and recently deployed in offshore Brazil. The system is a specialized two-module slop water treatment unit deployable on any drilling environment. The treatment process uses a combination of chemical and physical processes such as demulsification, flocculation, settling, and filtration to separate SBM and SBM fractions from the slop water into their main components. Testing was conducted to ensure that the system would have the capacity to treat SBM-contaminated waste to comply with the Brazillian Resolutions for Effluents Discharge (Conselho Nacional do Meio Ambiente Resolutions - CONAMA n° 357/05 and 430/11). The tests involved adjusting the system to operate within the limits established by the local legislation, which establish very conservative concentrations of metals and hydrocarbons, amongst other parameters, that effluents must meet before being discharged in continental or oceanic bodies of water. The results presented in this paper show that, with minor adjustments, the system can produce an effluent that complies with all necessary parameters for discharge at an offshore location. This prevents significant risks in transport and disposal, as well as the costs associated with them. This study has shown that the use of such a system is not only environmentally advantageous, but also economically significant as it helps minimize waste and increases drilling fluids reuse and profit margins in drilling operations. In Brazil, the use of this technology has an innovative profile and it is a tool that can contribute to reducing the high volumes of drilling waste that are currently transported onshore for waste disposal. The next step, before operational use of this technology in Brazil, is the agreement of a monitoring plan with the environmental agency.

Establishing a regulation for the use and discharge of drilling and completion fluids in Brazil has been a challenge. The lack of specific procedures and limits for some of the environmental control parameters has been generating difficulties for the final approval of these fluids, requiring additional efforts and provoking discussions between the oil companies, suppliers and the Brazilian environmental authority. One of the most relevant control parameters required for the use and discharge of fluids in the environmental permitting processes is the evaluation of acute and chronic toxicity on marine organisms. Even though the limit required for acute toxicity using the mysid shrimp Mysidopsis juniae is well defined (96-hr LC50 >30,000 ppm of SPP), there is not a limit established for the chronic toxicity using the larval stages of the sea-urchin Lytechinus variegatus, making the acute value the only established parameter used to define the approval of the fluids. Therefore, although chronic results are being generated for several fluid formulations, due to the lack of a specific limit, no direct use is being made of these results. The main purpose of this work is to contribute to the knowledge and proper use of toxicity results by comparing the values obtained for acute and chronic tests. For this evaluation, results obtained for different types of drilling and completion fluids will be used, both aqueous fluids (AF) and non-aqueous fluids (NAF). The results were analyzed by statistical tools to determine if a correlation between the two types of toxicity assays is feasible, considering the type of fluid evaluated.