There is an extensive network of infrastructure in the oil and gas industry between hydrocarbon sources and their final consumers. One of the most important installations is in the upstream industry, which includes production, transmission, and storage. Disruption in any of these units not only stops its performance but also negatively affects the performance of downstream units.1
Carbon steels (CS) are the main materials in the oil and gas industry. The use of CS reduces capital costs, but it increases operating costs, because of requiring inhibition, inspection, monitoring, and staffing.
Utilizing corrosion inhibitors is one of the common methods for controlling internal corrosion of CS in the oil and gas industry (continuous or batch injection). Many commercial corrosion inhibitors are now available and new products are being introduced for use in more corrosive environments. With a proper corrosion management system, using CS materials can be workable in conditions with excessive corrosion.2-4 Corrosion management is a systematic, active, and continuous process that is technically sound, economically appropriate, and safe in terms of people, infrastructure, and the environment.1
Corrosion management includes different stages and different models have been proposed for their implementation in oil and gas companies, the most important of which is the NACE International 2016 model.5
One of the main challenges in corrosion management is to determine the key indicators for chemical management.5 Key performance indicators (KPIs) have been introduced to monitor corrosion management systems.6
This article is focused on a number of indicators that have been defined and implemented to measure the performance of corrosion inhibitor management in the upstream oil and gas industries of Iran. After the introduction of these indicators, the results of measuring KPIs in the onshore and offshore regions were measured and discussed.
Key Performance Indicators
Nowadays, the analysis of the performance of existing systems to achieve organizational goals is very important in many manufacturing processes. Through performance management, it is possible to identify the strengths and weaknesses of the management system and, as a result, move toward improving productivity by emphasizing the elimination of weaknesses. For this purpose, it is necessary to select indicators that can be calculated in a structured way and their results be used to improve the management process.7
Therefore, KPIs are a criterion for measuring the efficiency of the management system and determining strategies for controlling corrosion and maintaining integrity. In fact, the KPIs provide an early warning system against unexpected leaks and breakdowns that compromise mechanical integrity and performance as well as health, safety, and the environment.8-9 With the help of KPIs, any industrial complex can plan and implement decisions that affect the safety of people, improve production, improve operations, and reduce expenses.9
To evaluate the management status of corrosion inhibitors used in the upstream oil and gas industries, KPIs were defined at three levels. These levels are defined based on the use of indicators at different management levels. These three levels are described below.
The first level of these indicators is used for top managers and to make major decisions for the organization. To understand Level 1 indicators, there isn’t the need for a lot of corrosion information and the indicators are mainly financial. In fact, in this type of report, the purpose of presenting corrosion management data is to link risk sources to their potential future costs.
The second level of KPIs is defined for the middle managers and used for obtaining management strategies. At Level 2, the indicators are mostly defined to measure the degree of compliance of the activities performed with previous plans, and by observing these indicators, managers can evaluate the successful performance of the system.
The third level of these indicators is mainly used by operational unit managers and corrosion experts to modify existing procedures. Level 3 indicators are indicators that determine the degree of successful performance of the system in compliance with corrosion control criteria and are related to the technical factors of the facility being serviced.
The defined indicators for managing the corrosion inhibitors used in upstream oil and gas industries are presented in Table 1, Table 2, and Table 3 . Also, these KPIs can be used to manage other chemicals, such as scale inhibitors, biocides, oxygen scavengers, etc.
The KPIs of Levels 2 and 3 were evaluated in the two onshore and offshore oil fields in Iran in 2019 and 2020. The results are shown in Figures 1 and 2. The results of calculating the KPIs of Level 2 in onshore and offshore regions showed that except for the pigging index in the onshore location, which decreased in 2020 compared to 2019 and is in an unfavorable situation, other indicators in 2019 and 2020 are in good condition.
Regular pigging is one of the factors affecting the performance of corrosion inhibitors. In many oil and gas pipelines, factors such as sand deposition and microorganisms reduce the performance of corrosion inhibitors and affect their efficiency. Factors such as lack of installed pigging equipment in pipelines have reduced this index. Therefore, it is necessary to try to increase the value of this index by conducting appropriate studies.
Among the KPIs of Level 3, availability and corrosion rate indicators are the most important. The corrosion rate indicator is in sufficient condition for both oil regions, but the availability indicator is in a relatively sufficient condition for the onshore region and in an unfavorable condition for the offshore field.
The value of this indicator directly affects the performance of the injection system and with increasing the value of the availability indicator, the amount of corrosion in most cases decreases to a desirable level. Studies have shown that the lack of timely supply of corrosion inhibitors is one of the important factors in reducing the value of this indicator. Injection rate indicator is another important performance indicator from Level 3. Decreasing or increasing the injection rate relative to the acceptable range will increase the corrosion rate and costs, respectively, and will have negative effects on the downstream industries.
Depreciation of the pumps is the most important reason for not injecting the inhibitor properly in the specified dose. In both onshore and offshore regions, this index was in an unfavorable situation in 2019 and 2020. Due to the fact that the pumps directly affect the performance of the injection system and in the case of improper operation, they cause injection in an inappropriate range or non-injection of the chemical, it is important to pay special attention to this part of the injection system.
As can be seen from the index, a large amount of injection system repair activities are related to pumps. Therefore, since the performance of the pumps has a direct impact on the efficiency of the injection system, old pumps need to be upgraded or prevent them from malfunctioning by installing high-quality parts. Also, pumps should be prevented from failure by carrying out more rigorous preventive activities.
In order to monitor the corrosion rate, appropriate methods such as corrosion coupons and electrical resistance and linear polarization probes can be used. Using inappropriate methods can lead to incorrect results and subsequent wrong decisions. In the onshore field, the simultaneous use of corrosion coupons, probes, and measuring the amount of iron has caused the favorable situation of this indicator.
However, the amount of corrosion monitoring indicators in the offshore field caused an unfavorable situation.
The most importa3nt KPIs for effective management of corrosion inhibitors and injection systems of upstream oil and gas industries were introduced at three levels. The KPIs defined for the two operational areas onshore and offshore in Iran were examined. Among the defined indicators for the onshore operational area and offshore field, 12 and 10 KPIs were implemented and calculated, respectively.
In total, in both oil areas, the KPIs of Level 2 were in the desired condition, but the KPIs of Level 3 were in poor condition in most cases. By examining the KPIs, a relatively good view of the current state of corrosion inhibitors and injection systems in these fields was obtained. Also, by implementing and calculating other KPIs, a more favorable situation can be achieved in the management of corrosion inhibitors and injection systems and reduce the risk of corrosion.
The authors gratefully acknowledge management of research and technology of the National Iranian Oil Company (NIOC) for supporting the work.
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