Environmental Risk Management of Discharges from E&P Activities in the North Sea

Abstract

Abstract In 1998 Norwegian oil industry, together with the authorities, initiated the "zero discharge" work. As a result of this co-operation, the target for the Norwegian offshore operators is set to achieve "zero harmful discharges" to the marine environment within 2005. The need for a system to quantify and document the potential harm of different discharges became evident as a result of this, and thus, the Environmental Impact Factor (EIF) for produced water discharges was developed in 1999 (presented at the SPE HSE 2000). This management tool, based on environmental risk assessment principles known from the EUs Technical Guideline Document (TGD) [14], has now been fully implemented in all Statoil's fields in the North Sea. The present paper outlines the utilisation of the EIF as a management tool and environmental performance indicator, and gives a number of practical examples of application of the system. The EIF has since 1999 also been developed further to cover discharges from drilling operations. Several pilot studies have been undertaken during this development, and the present paper gives the status of this activity and shows examples from drilling waste risk assessment in the Caspian Sea and the Faroe-Shetland channel. Further development of the EIF based risk management systems also includes linking air emissions and discharges to sea in a total environmental balance approach. The present paper will outline how this is handled in our present risk management system. Introduction Statoil's environmental impact management is currently based on the "Zero impact" mindset, meaning that the ultimate objective is to remove all potential environmentally harmful discharges [1]. In general, a number of technological approaches are being considered and developed to meet this challenge:Re-injection (cuttings and produced water)TreatmentWater shut offDown-hole separationRemoval or replacement of chemicalsTransportation to shore, deposition or recycling (Total fluid management) To meet the "zero impact" goal in a cost-efficient manner, a discharge management tool able to quantify the environmental benefit of implementing one or more of the above technologies for a specific field, is needed. Such a system should enable the operator of a specific field to identify and rank different discharge reducing measures on a cost/benefit basis, and also allow direct comparison with other fields within the actual area. The operator would, as a result of such considerations be able to present a strategy for reaching the state of "zero impact", and to identify the most important actions or milestones on the way. Through development and application of different environmental risk assessment systems the past years have provided the possibility to better understand and predict the potential environmental impact of discharges from offshore platforms. The development of the DREAM (Dose related Risk and Effect Assessment Model) [2] has resulted in a risk assessment tool to quantify and predict the potential long-term environmental effects, related to internal concentration (body burden) from biological uptake of produced water components, discharged to the water column. However, the present "body burden-related" version of the model is limited to only a number of polyaromatic hydrocarbons (PAHs) and alkylated phenols present in produced water.