Field testing of electrochemical noise monitoring has been conducted at the Simonette sour oil processing facility since August of 1997. Results from the installation at the Simonette sour oil processing facility are promising and have provided valuable insight into which process variables significantly affect corrosion rates and mechanisms in the system. Because electrochemical noise measurements allow monitoring of corrosion activity in real time, it has been possible to correlate specific changes in process conditions with corrosion events. Data from the electrochemical noise probe installed at the Simonette facility has been correlated to process changes as well as used to evaluate the chemical program in the stabilizer system, including measurement of the inhibitor film persistency. The electrochemical noise data was also used to define the effect of producing acid treatment fluids from wells into the battery on corrosion in the stabilizer system.
Electrochemical noise monitoring involves simply recording and analyzing the random fluctuations in potential and current between two identical electrodes. 1 Monitoring these minute fluctuations or 'noise' allows corrosion engineers to record corrosion events as they occur with a high degree of confidence that the electrodes (being the same material as the pipe or vessel being monitored) are corroding in a similar manner as the equipment of concern. This technique is particularly useful because one is able to recognize changes in system corrosivity in real time as well as to detect to localized corrosion events. 2 For the past 20 years, utilization of electrochemical noise monitoring has been largely limited to the laboratory 3 due to the vast amounts of data it generates, the sensitive instrumentation required to make the measurements and the expert data analysis that was essential to ensure accurate conclusions. The demand for equipment that would allow field application of this technique has been increasing over recent years and with improved instrumentation and software technology, an economic response to these demands is now possible. Bridging the gap from expert analysis in a lab environment to simple analysis at the field level while minimizing the loss of important information is difficult. It is a very gradual process that involves understanding the system being monitored, the corrosion mechanisms involved and how a particular probe will react in a particular system. Experiences presented here will illustrate the value of electrochemical noise as a field-level corrosion monitoring technique. This paper will present some of the data gathered from a stabilizer system in a sour oil processing facility. Also presented is an overview of how electrochemical noise data has been used to evaluate the chemical program and identify operating parameters critical to corrosion in this particular system.
SIMONETTE SOUR OIL BATTERY - PROCESS DESCRIPTION
The facility is designed to stabilize oil production from the Simonette A and B pools by removing light ends to produce a specification oil product. Associated solution gas is dehydrated and injected into a pipeline for processing at a nearby gas plant. The battery operates at the following conditions: 4 Inlet Pressure: 3450 kPa(g) Inlet Temperature: 45°C Daily Production: 1700 m 3 oil, 80 m 3 water, 600 103m 3 of gas The inlet stream to the battery contains approximately 1% H2S and 4% CO2.
Condensate Stabilizer System
A schematic of the stabilizer overhead system is shown in Figure 1. Oil is fed to tray 8 of the stabilizer from the inlet separators through the stabilizer feed heater where it is cross- exchanged with bottoms product from the stabilizer reboil
