The monitoring program used in the Danish Sector of the North Sea to manage microbiologically influenced corrosion (MIC) risk assessment for seven pipelines. Quantitative data on microbial activity was obtained from pigging debris using real-time polymerase chain reaction of MIC-causing microorganisms.
Corrosion in modern paper mills accounts for 30+% of maintenance expenses. Molecular microbiological methods (MMM): • Quantitative polymerase chain reaction (qPCR) and QuantArray were employed to examine MIC at four paper mills each with unique process characteristics and construction materials in the affected areas.
Microbiologically influenced corrosion (MIC) is one of the leading causes of equipment and pipeline failure in oil and gas industries. Cost-effective MIC management requires routine monitoring of microbial activities, periodic assessment of microbial risks in various operational systems, and accurate diagnosis of MIC failure. Traditionally, MIC diagnosis has been dependent on cultivation-based methods by inoculating liquid samples containing live bacteria into selective growth media, followed by incubation at a certain temperature for a pre-determined period of time. The conventional culturing techniques have been reported to severely underestimate the size of the microbial populations related to metal corrosion, among many inherited weaknesses of these techniques. As a result, accurate diagnosis of MIC failure is challenging because the conventional techniques often fail to provide a critical piece of evidence required for a firm diagnosis, i.e., the presence of corrosion-causing microorganisms in the failed metal samples. In this paper, we described applications of molecular microbiology methods in diagnosing MIC in a crude oil pipeline and crude processing facility. Molecular microbial analyses have provided a solid piece of evidence to firmly diagnose the MIC in a crude oil flow line, a stagnant bypass spool, and a global valve bypass pipe. The presence of a high number of corrosion-related microorganisms in upstream pipelines poses a high risk to downstream crude processing facilities for microbial contamination and corrosion failure in these facilities. An effective MIC management program should include routine monitoring of microbial activities and risk assessment, and effective mitigation program, such as scraping and biocide treatments.
MIC-causing microorganisms were investigated in a 16” diameter and 9.6 km long injection water pipeline. Nitrate was added to the water and pigging debris from the pipeline showed that both sulfate-reducing bacteria (SRB), nitrate-utilizing bacteria, and methanogens were present in numbers of 105 – 106 cells/g.
Microbial contamination is a major concern in oil/gas system or industrial water operation where it can result in multiple major corrosion issues and efficiency losses. Chemical treatment is the primary means to control microbial contamination, but due to changes in temperature and water sources, this results in major shifts in the microbial levels and populations which can influence the efficacy of these treatments.
Due to the shifts in the number of bacteria and the change in the dominant microbial species, optimal dosage of biocide is very difficult. Inadequate dosage regimen will result in major losses, whilst excess chemical dosage will incur unnecessary costs whilst also increasing the environmental load. A quick, reliable microbial measurement will help identify critical control points in the process and will allow optimization of dosing of the treatment program.
Agar growth, ATP, and media bottle testing have long been the standard for microbial detection, but these can lack the specificity, sensitivity and response time needed to adequately address the changing conditions in the industrial system described. The molecular-based approach, quantitative polymerase chain reaction (qPCR), described in this article, provides a near real-time method to measure bioburden, allowing operational decisions to mitigate issues to occur more rapidly.