Sonja Richter

The Role of Asphaltenes in Inhibiting Corrosion and Altering the Wettability of the Steel Surface

Abstract Asphaltenes (heptane insolubles) from a variety of crude oils have been identified previously as contributors to inhibition of internal corrosion of mild steel pipelines. However, the mech...

How Do Inhibitors Mitigate Corrosion in Oil-Water Two-Phase Flow Beyond Lowering the Corrosion Rate?

Corrosion inhibitors are commonly used to mitigate corrosion in oil and gas pipelines, and the choice of inhibitor for a particular oil field depends on the conditions of the field (oil chemistry, water chemistry, temperature, etc.). To find the optimum formulation for each field condition, extensive laboratory tests are carried out, which include corrosion inhibitor performance, foaming, and emulsification, to name a few. However, corrosion inhibitors can have the additional advantage of altering the wettability of the steel surface from hydrophilic (water wet) to hydrophobic (oil wet) by forming a hydrophobic adsorption layer on the steel surface. In the current work, the ability of chemicals to alter the wettability of the steel is investigated by measuring the static contact angle in a goniometer, as well as the dynamic wetting with a small scale flow apparatus, called a doughnut cell, especially designed for this purpose. The doughnut cell makes it possible to measure the water and oil wetting of a s...

Model Compound Study of the Mitigative Effect of Crude Oil on Pipeline Corrosion

Internal corrosion of crude oil pipelines can lead to spills that can be very costly, both financially and environmentally. The corrosion is controlled mostly by mitigation methods, such as through design or by the use of corrosion inhibitors. However, it has been observed that some, but not all, crude oils can have an inhibitive effect on their own. There are different mechanisms for crude oils to mitigate corrosion, such as inhibition through the water phase by inhibitor-like molecules native to the crude oil, wettability alteration from water wet steel surface to oil wet, thereby limiting the access of the water to the surface, or by lowering the interfacial tension between oil and water and facilitating dispersion of water in oil, which reduces the likelihood of corrosion by keeping the water from being in contact with the steel surface. Model compounds representative of the naturally occurring surface-active compounds commonly found in crude oil were tested for their effect on corrosion inhibition, w...

Reliability of Electrochemical Techniques for Determining Corrosion Rates on Carbon Steel in Sulfide Media

Abstract Effects of film formation on carbon steel in hydrogen sulfide (H2S) media may corrupt corrosion rate monitoring by electrochemical techniques. Electrochemical data from H2S solutions, biol...