Comprehensive Approach for Tracing Back Potential Sources of Organic Chloride in Crude Oil

Abstract

Organic Chloride is organic compound that have chlorine atoms as part of its chemical composition. Over the last four years, there has been continuous increase of number of research papers addressing the corrosion impact of organic chlorides in processes that includes high temperature like distillation towers. Where chlorine atoms start to detach and form free radicals in moisture wetting metal surfaces and result in severe corrosion of distillation towers. The Fact that led regulatory agencies to set a threshold number for maximum allowable content of organic chloride in crude beyond which crude is either not accepted or depreciated. That puts pressure on oil producers to maintain acceptable levels of organic chloride content. Companies working in Refineries are more familiar with organic chlorides than upstream operators are. Having the regulatory agencies pushing on setting limits on maximum allowable content of organic chlorides in crude. Now many operators are looking for a way to keep monitoring OC within limits and to define potential sources. Organic Chlorides rarely naturally exist in crude oil. That means there should be external source to contaminate crude such as chemicals used during the extensive operations in the oil field from drilling chemicals, stimulation, production, process, ETC. A leading example from Gulf of Suez, late 2021 a concern was raised on organic chlorides levels in crude of one of the prolific fields and the risk was to have negative impact on crude oil pricing. The risk would be dramatic on the large scale since all crude from different fields gather at the processing facilities then goes to same storage tank. An integrated Multidisciplinary in house task force team was formed to investigate the root causes for OC levels. The team reviewed MSDS of all chemicals consumed in all operations, qualified a Lab from Local Market for testing OC in crude Following ASTM D4929. Developed a comprehensive sampling and tracing strategy to be able to trace back to root causes. Over 5 Months of Monitoring, tracing and correlation between ongoing daily operations and OC levels. In addition to testing chemicals for OC. It was concluded that batches of organic solvent from one supplier are contaminated by OC. Contaminated Batches were quarantined and not used for daily operations. Another supplier was qualified for temporary supply of this type of solvent. As a result of the deep investigation a set of lessons learnt and recommended practices were generated and communicated with different disciplines for awareness and compliance to maintain OC levels manageable. Which in return saved operator company from the risk of depreciation of Crude oil price. Testing Chemicals with organic components are key for eliminating OC in crude and this should be done in Batch basis.