A risk-based approach to produced water management in offshore oil and gas operations

Abstract

Produced water is a waste of significant concern due to its high volume being produced every day and complex chemical composition. In order to meet environmental regulations and standards, different techniques can be used to treat produced water. This paper first summarizes produced water composition, its related environmental impact, regulations, and standards, as well as a possible combination of different treatment techniques. This paper aims to develop a generic framework for a risk-based approach to produced water management. The proposed methodology considers the integration of environmental, technical, and economic risks in the decision-making process for produced water management. Environmental risk assessment is conducted by DREAM, Failure Mode and Effects Analysis is used to estimate technical risk, and cost-benefit analysis is performed to calculate economic risk. To integrate all the risk values, acceptable risk levels are set and compared to the calculated risk values. Experts assign weighting factors by using pair-wise comparison. The sum of the multiplied weighting factors to the ratio of calculated-acceptable risk values gives the final integrated risk. This framework can help to examine and select the most suitable treatment or reuse technique or identify potential areas for improvement in a specific site. The estimated risk can be used to justify the selection process. A case study on the produced water treatment in Thunder Horse Oil Field is presented to demonstrate the application of the proposed framework.