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Collaborating Authors
Molecular Deep Dive into Oilfield Microbiologically Influenced Corrosion: A Detailed Case Study of MIC Failure Analysis in an Unconventional Asset
Leach, David G. (Chevron Corporation) | Wang, Wei (Chevron Corporation) | Yan, Chao (Chevron Corporation) | Mattis, Dillon (Chevron Corporation) | MacLeod, Ron (Chevron Corporation) | Wei, Wei (Chevron Corporation)
Abstract This work details a microbiologically influenced corrosion (MIC) failure analysis case study for a produced water pipeline. A pipeline in a shale and tight asset experienced heavy corrosion and ultimate failure within a 7-month period, with estimated corrosion rate at 161 mils per year (MPY), or 4.1 mm per year (MMPY). Upon removal by the inspection team, heavy white deposit buildup (a suspected microbial biofilm) was observed directly associated with the corrosion failure on top of a black scale underlayer. Detailed assessments were performed using ATP photometry, qPCR speciation, and 16S rRNA gene sequencing to profile the microbial population present, which was dominated by high-risk anaerobic microbial strains such as sulfate-reducing bacteria and methanogens. Scale analysis confirmed iron carbonate and iron sulfides associated with microbial iron metabolism and corrosion, and scanning electron microscopy explored surface morphology. This study will lay out detailed root cause analysis and include best practices for MIC diagnosis and recommendations for future prediction and prevention in oilfield assets. Introduction Microbiologically influenced corrosion (MIC) is a key oilfield problem associated with microbial activity, and can be described as the accelerated corrosion of surfaces (usually concrete or iron/steel) by the biological action of naturally present or externally introduced microorganisms. MIC incidents can occur anywhere that a system is exposed to the environment, where microorganisms can enter often via fluid flow and colonize various surfaces for their own growth. MIC is a persistent concern in practically any upstream, midstream, or downstream system where water could be present for microorganism colonization, including topside, subsurface, aerobic (with oxygen), anaerobic (without oxygen), and at extreme temperatures and salinities. This includes subsurface reservoir and well tubing, oilfield separators, fluid pipelines, water dump lines, relief valves, treatment facilities, etc. MIC failures result in process upsets, loss of containment, lost production opportunities, and increased operating expenses.
- Well Completion > Well Integrity > Subsurface corrosion (tubing, casing, completion equipment, conductor) (1.00)
- Production and Well Operations (1.00)
- Health, Safety, Environment & Sustainability (1.00)
- Facilities Design, Construction and Operation > Pipelines, Flowlines and Risers > Materials and corrosion (1.00)
ABSTRACT The oil and gas industry has historically recognized sulfate-reducing and acid-producing bacteria as problematic microorganisms and tailored identification, monitoring and microbiocide programs around these key microbial populations. In the last decade, the adoption of nucleic acid based monitoring methods, such as metagenomics and qPCR, has allowed the industry to identify additional metabolic classes of bacteria and archaea that are involved in causing operational issues in oil and gas production system. As the DNA based testing has become more cost effective and accepted across the industry, a large amount of knowledge has been gained about the problematic microbial populations in each system. The expanded microbial population knowledge base may lead the operator to ask the following questions: 1) now that we know we have each of these different problematic organisms in our system, would we treat the system differently to control these microbial populations and the issues they cause; and 2) is there a biocide that consistently performs well against all problematic microbes? The kill efficiency of various oil and gas industry biocides was evaluated against pure cultures of a common oil and gas industry iron reducer, sulfate reducer, acid-producer and a methanogen. Biocides that performed well against each individual problematic species as well as the biocides that consistently performed well against all microorganisms were identified. INTRODUCTION The role of microorganisms as causative agents of fouling, corrosion, and reservoir souring in oil and gas operations is well-documented. Particular focus has been placed on the role of sulfate-reducing bacteria (SRB) and acid-producing bacteria (APB). SRB pose a particular threat to the industry due to their ability to reduce sulfates to sulfides, releasing sulfuric acid and hydrogen sulfide (H2S) as byproduct. H2S gas is not only extremely toxic and flammable, but it causes souring of the petroleum product, resulting in reduced quality and increased handling costs. Unrelated clades of bacteria are capable of sulfate reduction. Bacterial clades where sulfate reduction occurs include members of the Firmicutes, the delta subgroup of the Proteobacteria, Deferribacter, and Nitrospira as well as several archaeal clades. A hallmark of the SRB is that they encode the DsrA and DsrB dissimilatory sulfate reductase subunits, which can be used as a molecular marker. However, despite the focus on sulfate reducing bacteria, there are additional clades of sulfur and thiosulfate reducing bacteria that lack DsrA/B and yet still generate H2S through other pathways such as peptide fermentation. There is mounting evidence supporting a role for these non-SRB sulfidogens in generating problematic H2S in the oilfield. Bacteria capable of dissimilatory Fe(II) reduction (IRB) also belong to disparate clades of bacteria. Representative IRB, including Shewanella (a gamma proteobacteria) as well as members of the Deltaproteobacteria, including Geobacter, Desulfuromonas, and Pelobacter APB is the least defined metabolically. Many APB produce organic acids, such as acetic, lactic, and butyric acids. A few types of acid producing bacteria, the true acidophiles, produce highly corrosive inorganic acids, such as sulfuric acid.
- Asia > Middle East > Yemen (0.93)
- Asia > Middle East > Saudi Arabia (0.93)
- Africa > Sudan (0.93)
- (4 more...)
- Energy > Oil & Gas > Upstream (1.00)
- Water & Waste Management > Water Management > Constituents > Bacteria (0.69)
- Production and Well Operations > Well Operations and Optimization (1.00)
- Production and Well Operations > Production Chemistry, Metallurgy and Biology > Corrosion inhibition and management (including H2S and CO2) (1.00)
- Health, Safety, Environment & Sustainability > Health > Noise, chemicals, and other workplace hazards (1.00)
- Facilities Design, Construction and Operation > Pipelines, Flowlines and Risers > Materials and corrosion (1.00)
Abstract Microbiological risk evaluation of topside systems of four floating production storage and offloading in West Africa was carried out over a period of four years. Field samples were taken, and DNA analyzed using next-generation sequencing technology to identify and classify the microbial population present on the facilities. Several classes of bacteria and archaea were sequenced and identified from the samples, including those that have been shown to play key roles in biofouling, microbiologically influenced corrosion and biogenic hydrogen sulphide generation in oil and gas production systems. The classic microbial population according to metabolic classes associated with oil and gas production systems were identified. The study found that of the 137 microbial genera identified, 45.3% were associated with biofouling, 29.9% with microbiologically influenced corrosion, 29.1% with a H2S/MIC risk and a 2.9% population did not have a clear link to any of these risks. There was at least 98% relative abundance of bacteria population in the samples from all FPSOs, implying a significant exposure to the risks posed by microbial growth and proliferation. Introduction The incidence and proliferation of microbial population in oil and gas production facilities can have undesirable consequences on upstream, midstream and downstream production systems. Microbes thrive in the anaerobic conditions encountered in these systems and are supported by nutrients and metabolites found in produced water. Although the majority of process and water injection systems are susceptible to microbial fouling, the development of microbial activity is exacerbated by specific conditions such as stagnant fluids or the presence of deposits. Threats of microbiologically influenced corrosion (MIC) and other challenges associated with microorganisms have become valid as more cases are reported. While MIC, biofouling (BF), and reservoir souring are three of the most common problems associated with microbes, many other production issues can be attributable to microbial activity including: employee infections, filter plugging, loss of injectivity, and metal sulfide deposits.
- Africa > West Africa (0.61)
- North America > United States > Texas (0.29)
- Energy > Oil & Gas > Upstream (1.00)
- Water & Waste Management > Water Management > Lifecycle > Disposal/Injection (0.55)
- Reservoir Description and Dynamics > Improved and Enhanced Recovery (1.00)
- Production and Well Operations (1.00)
- Facilities Design, Construction and Operation > Pipelines, Flowlines and Risers > Materials and corrosion (1.00)
- Facilities Design, Construction and Operation > Offshore Facilities and Subsea Systems > Floating production systems (1.00)
Abstract Here, we coupled successive rounds of molecular microbial methods (MMM) to calibrate adenosine triphosphate (ATP) readings to trend Halanaerobium fouling in unconventional wells. ATP was then used to drive a biocide efficacy study, which resulted in selecting a glutaraldehyde/quaternary amine (quat) blend. This selection was partly supported by literature searches, which showed that quats have been effective on Halanaerobium. ATP monitoring was then used to direct the success of a downhole biocide treatment program for horizontal wells. Since sessile samples were not routinely available, planktonic samples were used. Over two years of reviewing the treatment results of approximately 30 wells in a single lease, where multiple sample points were available, we found that most treatments were successful in returning/or maintaining wells within KPIs. The operator has experienced reduced failures and currently relies on MMM supported ATP to monitor multiple leases where Halanaerobium is present. Introduction The development of shale plays has introduced large water quantities to diverse downhole environments. The most recent reduction in oil price has put more focus on produced water reuse since "clean" frack water sources (e.g. potable, municipal) tend to be non-economical. Compounding the problem, in some cases operators have used less effective, underdosed, or forgone a completion biocide treatment to save on cost. The downhole environment has been shown to act as a selection pressure on microbial diversity. Given time, this in turn leads to a higher biological load in unconventional wells. This reservoir entrenchment of microorganisms leads to souring, plugging by biomass or iron sulfide, and corrosion. These problems persist downhole, as well as in downstream production, creating a health and safety concern. The cost of poor biological treatment during the frack becomes poor return on investment during production in the form of workovers and producing well down time. Sulfate reducing bacteria (SRB) and acid producing bacteria (APB) are usually the suspected culprits in the oil patch for souring and corrosion. This is, in large part, due to their presence being readily and routinely accessible through culturing. Culture media, known colloquially as bug bottles, are known to only allow for the growth of ˂1% of organisms present and require 14-28 days for detection. However, recent studies have shown that a guar-utilizing acetic acid producing bacteria can lead to corrosion and, under the right conditions, souring. It was previously reported that this organism (at least in part) is not compatible to conventional culture media. Therefore, it is difficult to unambiguously detect this microbe without the use of molecular microbial methods (MMM). Historically, MMM typically required a 4 week turnaround period, and a high per sample cost (approximately 100X the cost of using culture media) which has limited widespread application. In the past few years, MMM market maturity in the O & G industry has resulted in these costs being reduced ten-fold and data can be returned to the customer in as soon as 2 weeks' time.
- Geology > Mineral > Sulfide (0.54)
- Geology > Petroleum Play Type > Unconventional Play > Shale Play (0.48)
- Energy > Oil & Gas > Upstream (1.00)
- Materials > Chemicals > Commodity Chemicals > Petrochemicals (0.35)
- North America > United States > Texas > Permian Basin > Yeso Formation (0.99)
- North America > United States > Texas > Permian Basin > Yates Formation (0.99)
- North America > United States > Texas > Permian Basin > Wolfcamp Formation (0.99)
- (28 more...)
Molecular Identification Of Mic Bacteria From Scale And Produced Water: Similarities And Differences
Larsen, Jan (Mærsk Olie og Gas AS ) | Skovhus, Torben Lund (Danish Technological Institute ) | Saunders, Aaron Marc (Danish Technological Institute) | Højris, Bo (Danish Technological Institute ) | Agerbæk, Mikkel (Danish Technological Institute )
ABSTRACT Culture-based methods of traditional microbiology applied to microbiological processes involved in reservoir souring and microbiologically influenced corrosion (MIC) pose a risk of yielding inadequate or contradictory results. Therefore, the industry calls for more accurate and faster techniques. The need for in-situ cultivation-independent methods has over the past ten years facilitated the development of several analytical methods for determination of bacterial identity, quantity, and to some extent function, applied directly to samples of the native population. This development has so far been limited regarding practical application and it has only recently been transferred to the oil industry. We have applied state-of-the-art molecular tools to monitor progressive corrosion attacks in an offshore oil facility in the Danish sector of the North Sea. We investigated the similarities and differences among MIC bacterial populations obtained from produced water and bacteria found in corrosion spots in a X-mas tree from a producing well. Molecular methods proved to be a powerful tool in identifying the involved microorganisms and the most likely corrosion process. The entire population of bacteria found in the corrosion deposit was characterised and found to consist almost entirely of sulfate reducing bacteria (SRB), of which the critical species were identified. Additionally, we determined that the bacterial populations that are present in the produced water are somewhat different to those found in the corrosion deposit. Many of the bacteria in the produced water are involved in souring processes and the production of H2S. Future research is focussing on the development of a direct and rapid method to specifically measure the critical SRB involved in MIC, both in deposits but also as a routine monitoring tool in the produced water. This new and improved microbiological approach is an important criterion in designing and testing remedial actions towards reservoir souring and MIC. INTRODUCTION In the oil industry, a great deal of the microbiological monitoring is still based on cultivation techniques which have an inherent bias regarding strain isolation and growth. While great advances have been made in cultivation techniques, it is now accepted that only 0.001-15% of the viable bacteria are culturable by these classical microbiological methods1. Thus, with culture-based methods only a fraction of the organisms are detected. Furthermore, the growth of many bacteria is slow and results are available only after 30 days for some types. Faster and more reliable microbiological monitoring techniques are required if specific bacteria are to be used as indicators for subsequent remedial action (e.g. adjusting biocide and nitrate chemical treatments), to assess risk of microbiologically influenced corrosion (MIC), or as an early warning regarding souring of oilfields. Direct analysis of environmental samples using culture-independent, DNA-based methods meets these requirements as they enable the rapid identification and quantification of all microorganisms ? including the vast majority that are not able to be cultured. In addition, the molecular analyses can be made directly on the sample resulting in a faster response time (within a few days) thereby minimizing changes in the bacterial population due to sample storage.
- North America > United States (1.00)
- Europe > Denmark > North Sea (0.50)
- Energy > Oil & Gas > Upstream (1.00)
- Water & Waste Management > Water Management > Constituents > Bacteria (0.35)
- Europe > Denmark > North Sea > Danish Sector > Central Graben > Block 5505/17 > Dan Field (0.99)
- Europe > Denmark > North Sea > Danish Sector > Central Graben > Block 5505/13 > Halfdan Field > Maastrichtian Formation (0.99)
- Europe > Denmark > North Sea > Danish Sector > Central Graben > Block 5505/13 > Halfdan Field > Danian Formation (0.99)
- (3 more...)
- Reservoir Description and Dynamics > Improved and Enhanced Recovery (1.00)
- Production and Well Operations > Production Chemistry, Metallurgy and Biology (1.00)
- Health, Safety, Environment & Sustainability > Environment > Water use, produced water discharge and disposal (1.00)
- Facilities Design, Construction and Operation (1.00)