ABSTRACT

CO2 dominated corrosion has been extensively studied under varying conditions and significant number of the corrosion inhibitors used in the industry today can provide adequate corrosion protection but corrosion mitigation for high shear and high temperature (HTHS) still remains a challenge. Recently, with the rise in "green" concept in O&G sector, customers are asking for products that can not only protect their assets but cause little or no harm to the environment in which they operate.

This paper emphasizes the development of low toxic, subsea umbilical certified corrosion inhibitors that provides excellent corrosion protection GCR (General Corrosion Rates) < 3mpy and localized corrosion performance (pitting depths <10 μm) under high shear and high temperature conditions with limited impact on the oil water separation. The products have been qualified under several test conditions with varying corrosivity in autoclaves. All the products qualified in this work earned a silver ranking using the Offshore Chemical Notification Scheme (OCNS) CHARM model, indicating low environmental impact.

INTRODUCTION

Terms such as (green, low toxicity, biodegradability, log Pow or environmentally friendly) are often used interchangeably for product classification, however, their definitions can be very vague.1 Regulatory agencies in various parts of the world employ different methods to classify chemical products and assess potential impacts from their discharge into marine environment. Some practice the hazard-based approach while others use the risk-based approach (Figure 1). Some use both hazard and risk based approaches, combining pre-screening of hazard data with a risk based assessment model for marine discharges called CHARM (Chemical Hazard Assessment and Risk Management)".

The hazard-based approach measures the toxicity, biodegradability, and bioaccumulation while the risk-based approach considers the dosage of the product and environmental conditions. In CHARM model, Hazard quotient (HQ) is calculated which is the ratio of the predicted environmental concentration (PEC) and predicted no effect concentration (PNEC)2,3 and signifies the degree of impact to the environment.

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