Abstract Microbial activity has a severe impact on corrosion of oil production facilities and reservoir souring. Bacterial growth and metabolic products significantly aggravating the corrosion of pipelines, manifolds, and separators which increases the risk of system failure. Microbiologically influenced corrosion (MIC) is caused by the turnover of hydrogen, sulfur and organic carbon driven by sulfate-reducing bacteria (SRB), sulfate-reducing Archaea (SRA) and methanogens. One important risk management tool is biocide dosage to control microbial activity in offshore oil production systems. To obtain a cost-efficient biocide treatment strategy it is important to determine biocide efficiency using microbiological assays (bioassays) that comprise quantitative measures of: Bacterial growth. Activity of specific bacterial groups related to MIC and souring. Accumulation rates of carbon dioxide, sulfide and methane. The bioassays presented in this paper investigate microbial activity in produced waters from an offshore platform where different biocides were tested. Based on molecular microbiology methods (MMM) it was evident that bacterial growth occurred in production water without addition of biocide at growth rates up to 0.46 1/d. Furthermore, active growth of both SRB and Archaea indicated that microorganisms that may be involved in corrosion processes were active in cell numbers of 105 cells/mL. Concurrently, depletion of sulfate and accumulation of total inorganic carbon, sulfide, and methane due to microbial activity was measured and maximum rates were used in combination with MMM to evaluate activity in bioassays with and without biocide. The results showed that addition of biocide in both injection and production waters decrease cell numbers and metabolic activity of SRB and methanogens. In general bioassay results can be used to evaluate the efficiency of biocides and nitrate at different dosage concentrations. The bioassays are most valuable when implemented in a risk assessment model for MIC and souring of oilfield reservoirs.
Abstract Operating offshore oil and gas production facilities is often associated with high risk. In order to manage the risk, operators commonly use aids to support decision making in the establishment of a maintenance and inspection strategy. Risk Based Inspection (RBI) analysis is widely used in the offshore industry as a means to justify the inspection strategy adopted. The RBI analysis is a decision-making technique that enables asset managers to identify the risk related to failure of their most critical systems and components, with an effect on safety, environmental and business related issues. Risk is a measure of possible loss or injury, and is expressed as the combination of the incident probability and its consequences. A component may have several associated risk levels depending on the different consequences of failure and the different probabilities of those failures occurring. Microbiologically Influenced Corrosion (MIC) is a degradation mechanism that has received increased attention from corrosion engineers and asset operators in the past decades. In this paper, the most recent models that have been developed in order to assess the impact of MIC on asset integrity will be presented and discussed. From a risk perspective, MIC is not satisfactorily assessed by the current models and the models lack a proper view of the MIC threat. Therefore, a review of known parameters that affect MIC is presented. The mapping and identification of parameters is based on the review of past models and an extensive up-to date literature study. The parameters are discussed and subsequently combined in a novel procedure that allows assessment of MIC in a RBI analysis. The procedure is sub-divided into one screening step and a detailed assessment, which fits the recommended approach to assess risk in a RBI analysis. To illustrate the practical application of the developed procedure a field case is presented.
ABSTRACT A real-time quantitative PCR (RTQ-PCR) method for measuring the abundance of Pseudoalteromonas species in marine samples is presented. PCR primers targeting a Pseudoalteromonas -specific region of the 16S rRNA gene were tested at three different levels using database searches (in silico), a selection of pure cultures (in vitro), and a combined denaturing gradient gel electrophoresis and cloning approach on environmental DNA (in situ). The RTQ-PCR method allowed for the detection of SYBR Green fluorescence from double-stranded DNA over a linear range spanning six orders of magnitude. The detection limit was determined as 1.4 fg of target DNA (1,000 gene copies) measured in the presence of 20 ng of nontarget DNA from salmon testes. In this study, we discuss the importance of robust post-PCR analyses to overcome pitfalls in RTQ-PCR when samples from different complex marine habitats are analyzed and compared on a nonroutine basis. Representatives of the genus Pseudoalteromonas were detected in samples from all investigated habitats, suggesting a widespread distribution of this genus across many marine habitats (e.g., seawater, rocks, macroalgae, and marine animals). Three sample types were analyzed by RTQ-PCR to determine the relative abundance of Pseudoalteromonas ribosomal DNA (rDNA) compared to the total abundance of eubacterial rDNA. The rDNA fractions of Pseudoalteromonas compared to all Eubacteria were 1.55% on the green alga Ulva lactuca , 0.10% on the tunicate Ciona intestinalis , and 0.06% on the green alga Ulvaria fusca .
This chapter describes the workflow of transportation, sampling, and documentation of topsides pipework that exhibited a leak on an offshore oil platform. The example is pipework of the water injection system from an offshore oil platform in the North Sea. The purpose of performing testing and failure investigation was to identify the direct and underlying causes for the leak. The reader is guided with several checklists and additional literature for studying this topic in more detail at the end of the chapter.
Rapid Determination of MIC in Oil Production Facilities with a DNA-based Diagnostic Kit Torben Lund Skovhus; Torben Lund Skovhus 1 Danish Technological Institute, DTI Oil & Gas Center, Kongsvang Allé 29, DK-8000 Aarhus C, Denmark Search for other works by this author on: This Site Google Scholar Ketil Bernt Sørensen; Ketil Bernt Sørensen 1 Danish Technological Institute, DTI Oil & Gas Center, Kongsvang Allé 29, DK-8000 Aarhus C, Denmark Search for other works by this author on: This Site Google Scholar Jan Larsen; Jan Larsen 2 Maersk Olie og Gas AS, 50 Esplanaden, DK-1263 Copenhagen K, Denmark Search for other works by this author on: This Site Google Scholar Kim Rasmussen; Kim Rasmussen 2 Maersk Olie og Gas AS, 50 Esplanaden, DK-1263 Copenhagen K, Denmark Search for other works by this author on: This Site Google Scholar Michael Jensen Michael Jensen 2 Maersk Olie og Gas AS, 50 Esplanaden, DK-1263 Copenhagen K, Denmark Search for other works by this author on: This Site Google Scholar Paper presented at the SPE International Conference on Oilfield Corrosion, Aberdeen, UK, May 2010. Paper Number: SPE-130744-MS https://doi.org/10.2118/130744-MS Published: May 24 2010 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Get Permissions Search Site Citation Skovhus, Torben Lund, Sørensen, Ketil Bernt, Larsen, Jan , Rasmussen, Kim , and Michael Jensen. "Rapid Determination of MIC in Oil Production Facilities with a DNA-based Diagnostic Kit." Paper presented at the SPE International Conference on Oilfield Corrosion, Aberdeen, UK, May 2010. doi: https://doi.org/10.2118/130744-MS Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll ProceedingsSociety of Petroleum Engineers (SPE)SPE International Oilfield Corrosion Conference and Exhibition Search Advanced Search Abstract The use of culture-based microbiological methods is slow and can only measure the few sulfate-reducing Bacteria (SRB) that can be cultivated. Faster and more accurate techniques for the diagnostics of microbiologically influenced corrosion (MIC) are therefore required.This paper demonstrates the benefits of applying state-of-the-art molecular microbiology methods (MMM) to the identification and quantification of the microorganisms contributing to corrosion in oil production facilities. For quantification of troublesome microorganisms MMM can be applied directly to solid samples from the oil field without the need for culture media.The corrosion mechanism was investigated in two different cases: (i) a piece of piping with high corrosion rates from the water outlet of a separator from the Halfdan oil field, and (ii) a similar piece of piping from the Dan oil field with much lower rates of corrosion. The chemical distribution of elements was analysed using X-ray diffraction and the levels of MIC causing microorganisms were determined with qPCR (a DNA-based quantification method).The results showed that corrosion in the piping from Halfdan was caused by MIC. The results also showed that not only SRB were involved in the observed MIC. High numbers of sulfate-reducing prokaryotes (SRP) and methanogens were measured in material from the Halfdan separator with high corrosion rates. The methanogens were particular abundant close to the metal/scale interface. The data indicates that the high level of microorganisms in the Halfdan separator speeds up the corrosion process by efficiently consuming hydrogen released during dissolution of iron.Finally, the paper discusses the strength of applying qPCR as a standardized, high-throughput routine monitoring tool for MIC diagnostics when developing more reliable integrity management programs in the future. This study has shown that the improved molecular microbiological approach to MIC is important when designing and testing remedial actions towards MIC in oil field systems. Keywords: microorganism, halfdan hp separator, deposit, qpcr technique, larsen, corrosion rate, materials and corrosion, upstream oil & gas, oil field system, oil production facility Subjects: Pipelines, Flowlines and Risers, Materials and corrosion Copyright 2010, Society of Petroleum Engineers You can access this article if you purchase or spend a download.
Abstract Oilfield systems are a multifaceted ecological niche which consistently experience microbiologically influenced corrosion. However, simulating environmental conditions of an offshore system within the laboratory is notoriously difficult. A novel dual anaerobic biofilm reactor protocol allowed a complex mixed-species marine biofilm to be studied. Interestingly, electroactive corrosive bacteria and fermentative electroactive bacteria growth was supported within the biofilm microenvironment. Critically, the biotic condition exhibited pits with a greater average area which is characteristic of microbiologically influenced corrosion. This research seeks to bridge the gap between experimental and real-world scenarios, ultimately enhancing the reliability of biofilm management strategies in the industry. Importance It is becoming more widely understood that any investigation of microbiologically influenced corrosion requires a multidisciplinary focus on multiple lines of evidence. While there are numerous standards available to guide specific types of testing, there are none that focus on integrating biofilm testing. By developing a novel dual anaerobic reactor model to study biofilms, insights into the different abiotic and biotic corrosion mechanisms under relevant environmental conditions can be gained. Using multiple lines of evidence to gain a holistic understanding, more sustainable prevention and mitigation strategies can be designed. To our knowledge, this is the first time all these metrics have been combined in one unified approach. The overall aim for this paper is to explore recent advances in biofilm testing and corrosion research, to provide recommendations for future standards being drafted. However, it is important to note that this article itself is not intending to serve as a standard.
