Smart Fluids for Detecting Internal Corrosion Locations in Oil and Gas Pipelines

Overview

Main Objective

Develop a sensor concept to detect likely locations of internal corrosion in a natural gas pipeline using corrosion marker chemicals in the flowing gas and demonstrate its feasibility.

Public Abstract

In the last few years, internal corrosion caused approximately 7 to 20% of the pipeline incidents. In line inspection (ILI) of pipelines is used at certain fixed time intervals. ILI has limitations in gas lines. For example, at lower pressures, sufficient contact is not established with pipe walls for measurements. Geometrical features such as sharp bends, partially shut valves, internal debris buildup can all prevent the use of ILI. Additionally, ILI is expensive and is used only at long time intervals. For pipelines that cannot use ILI, alternative approaches include direct assessment, ball-type sensors, and fixed sensors. However, these approaches have significant limitations. Direct assessment cannot always be used and may miss certain locations due to lack of knowledge of pipe inclinations. Ball type sensors have shown many implementation issues, including the tendency to get stuck and mechanical fragility. Fixed sensors require accurate flow modeling and pipeline inclination angles for appropriate location. We propose using the gas stream itself to detect potential locations of corrosion by adding marker chemicals that bind with dissolved iron from the corrosion and emit an optical signal. This signal can be detected by placing a light detector on a cleaning pig with position location sensors that is already being used by pipeline companies. The project consists of four major tasks: Task 1 will optimize the marker chemical that will bind to aqueous corrosion products and will possess fluorescent organic groups. Task 2 will identify the conditions necessary for optimal detection, such as flow, pressure, temperature, water content, corrosivity, etc. and will assess interference issues. Task 3 will focus on demonstrating the technique using a laboratory pipe flow system that can be configured to reflect various inclination angles. Task 4 will identify the pathways for practical implementation.

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