1、 Item No. 24227 NACE International Publication 31205 This Technical Committee Report has been prepared by NACE International Task Group 075* on BiocidesOil and Gas Industry Selection, Application, and Evaluation of Biocides in the Oil and Gas Industry February 2006, NACE International This NACE Inte
2、rnational technical committee report represents a consensus of those individual members who have reviewed this document, its scope, and provisions. Its acceptance does not in any respect preclude anyone from manufacturing, marketing, purchasing, or using products, processes, or procedures not includ
3、ed in this report. Nothing contained in this NACE report is to be construed as granting any right, by implication or otherwise, to manufacture, sell, or use in connection with any method, apparatus, or product covered by Letters Patent, or as indemnifying or protecting anyone against liability for i
4、nfringement of Letters Patent. This report should in no way be interpreted as a restriction on the use of better procedures or materials not discussed herein. Neither is this report intended to apply in all cases relating to the subject. Unpredictable circumstances may negate the usefulness of this
5、report in specific instances. NACE assumes no responsibility for the interpretation or use of this report by other parties. Users of this NACE report are responsible for reviewing appropriate health, safety, environmental, and regulatory documents and for determining their applicability in relation
6、to this report prior to its use. This NACE report may not necessarily address all potential health and safety problems or environmental hazards associated with the use of materials, equipment, and/or operations detailed or referred to within this report. Users of this NACE report are also responsibl
7、e for establishing appropriate health, safety, and environmental protection practices, in consultation with appropriate regulatory authorities if necessary, to achieve compliance with any existing applicable regulatory requirements prior to the use of this report. CAUTIONARY NOTICE: The user is caut
8、ioned to obtain the latest edition of this report. NACE reports are subject to periodic review, and may be revised or withdrawn at any time without prior notice. NACE reports are automatically withdrawn if more than 10 years old. Purchasers of NACE reports may receive current information on all NACE
9、 International publications by contacting the NACE FirstService Department, 1440 South Creek Drive, Houston, Texas 77084-4906 (telephone +1 281/228-6200). Foreword The purpose of this technical committee report is to discuss the state-of-the-art considerations and methods for selecting, applying, an
10、d evaluating the use of biocides in oil and gas field operations. These field operations include stimulation, production, storage, transmission, hydrostatic testing, and water injection applications. This report is intended to be a resource for oil and gas professionals. In addition to providing inf
11、ormation on the selection, application, and evaluation of biocides, the report directs the reader to standard procedures, guidelines, textbooks, and regulatory documents for more in-depth information. This is achieved through the extensive use of references and an annotated bibliography. This report
12、 was prepared by Task Group (TG) 075 on Oil Industry Biocides. TG 075 is administered by Specific Technology Group (STG) 31 on Oil and Gas ProductionCorrosion and Scale Inhibition. It is published by NACE International under the auspices of STG 31. NACE technical committee reports are intended to co
13、nvey technical information or state-of-the-art knowledge regarding corrosion. In many cases, they discuss specific applications of corrosion mitigation technology, whether considered successful or not. Statements used to convey this information are factual and are provided to the reader as input and
14、 guidance for consideration when applying this technology in the future. However, these statements are not intended to be recommendations for general application of this technology, and must not be construed as such. _ * Chair Hartley H. Downs, Baker Petrolite, Sugar Land, Texas. NACE International
15、2 _ NACE International Publication 31205 Selection, Application, and Evaluation of Biocides in the Oil and Gas Industry Contents 1. Oil and Gas Field Microbiology. 4 Types and Classes of Bacteria in Oil and Gas Field Systems 4 Biofilms. 6 Factors Affecting Bacterial Growth Rate . 9 Problems Caused b
16、y Oil and Gas Field Bacteria 9 2. Oil and Gas Field Biocides . 10 Oxidizing Biocides 11 Nonoxidizing Biocides 13 Biocide Blends . 17 Alternatives to Chemical Biocides . 17 3. Monitoring and Surveying Oil and Gas Field Systems. 18 Typical Objectives for Monitoring and Surveying 18 Background Informat
17、ion Useful Prior to Field Work . 19 Sampling 19 Enumeration Methods 20 Typical Chemical and Physical System Parameters. 22 4. Implementing and Optimizing Biocide Treatment Programs. 23 Designing Biocide Programs . 23 Implementing Biocide Applications 26 Optimizing Biocide Treatments 28 5. Regulatory
18、 Aspects of Biocide Use 28 United States of America. 32 Europe and Scandinavia 34 References 35 Annotated Bibliography. 42 Appendix A: Glossary . 43 Figure 1: Reactions possible under tubercles created by iron-oxidizing bacteria . 5 Figure 2: Model of a biofilm based on confocal scanning laser micro
19、scope images 7 Figure 3: Strata within a typical biofilm and possible reactions within the strata . 8 Figure 4: Approximate percentage of nonionized hypochlorous acid in water as a function of pH at 20C (68F). 12 Table 1: Examples of Operational Problems That May Be Caused by Bacteria. 10 NACE Inter
20、national 3 Table 2: Approximate Percentage of Nonionized Hypochlorous Acid in Water as a Function of pH and Temperature 12 Table 3: Compatibility of Common Biocides with Various Metals and Elastomers. 15 Table 4: Background Information Useful Prior to Conducting Surveys . 19 Table 5: Partial List of
21、 Potential Sampling Locations. 20 Table 6: Correlation of the Number of Positive Serial Dilution Vials with the Concentration of Bacteria in the Sample 21 Table 7: Partial List of Potential Compatibility Issues 25 Table 8: System Parameters That Typically Affect Biocide Demand 26 Table 9: Contacts f
22、or Competent Authorities . 29 Table 10: Useful Web Sites 32 _ NACE International 4 Section 1: Oil and Gas Field Microbiology A detailed understanding and thorough evaluation of several issues are used in implementing an effective biocide program. This report is intended to provide oil and gas profes
23、sionals with the background that can assist them in considering treatment alternatives, selecting the most cost-effective treatment program, applying the technology using practices that comply with governmental regulations, and continuously monitoring and optimizing the treatment program. Through th
24、e extensive use of references and an annotated bibliography, the reader is directed to standards, guideline documents, publications, and textbooks for additional information. A glossary of terms is also provided in Appendix A of this report. The use of biocides in refinery and other industrial appli
25、cations is outside the scope of this report. Types and Classes of Bacteria in Oil and Gas Field Systems Identification and naming (taxonomy) of bacteria is an exhaustive science. To date, more than 5,000 species of bacteria have been identified, isolated, and named.1,2In virtually all oilfield syste
26、ms, multiple strains of bacteria coexist in symbiotic relationships.3-6Classification of each strain of bacteria in a population is further complicated by the fact that no single test can be used to quantify all types of bacteria that might be present in oilfield populations. Different types of grow
27、th media, some with nonstandard formulations, are normally used to begin to quantify the numbers and types of bacteria in a single population. For ease of discussion, microbiologists often group bacteria according to the organisms tolerance of oxygen, shape, optimum growth temperature, or metabolism
28、. Bacteria that use oxygen in their metabolism are termed strict or obligate aerobic bacteria. In contrast, obligate anaerobic bacteria do not grow in the presence of oxygen. Facultative anaerobes function either in the presence or absence of oxygen, and microaerophiles use oxygen, but prefer low le
29、vels. It is common to find bacteria with different oxygen requirements coexisting in the same system and in the same deposits. In highly oxygenated systems, for example, anaerobic bacteria often survive in tiny crevices in pipe surfaces that are out of the direct flow of the oxygenated water. Furthe
30、rmore, as populations of aerobic bacteria deposit on a system surface, oxygen diffusion to the surface is suppressed. This creates a reduced-oxygen environment in which microaerophiles and anaerobes can thrive, shielded from the oxygen in the system by the aerobic bacteria.1,2Microbiologists typical
31、ly group bacteria according to the shape of the bacteriums cell body (morphology). Bacteria are shaped as rods (bacillus), curved rods (vibrio), corkscrew curved rods (spirillum), and spheres (coccus). Shape alone, however, is not normally a good indicator of a bacterial type because a single strain
32、 of bacteria can take on different shapes depending on growth conditions, and many different species may have similar morphologies. A third way that bacteria are grouped is by the optimum temperature at which they grow. Thermophilic bacteria have maximum growth rates at temperatures above 50C (122F)
33、. Mesophiles grow best in the middle temperature range of 20 to 37C (68 to 99F). Other organisms called psychrophiles only grow well near freezing temperatures of 4 to 10C (39 to 50F). While each species of bacteria grows at an optimum temperature, it can also adapt and grow at temperatures outside
34、the ranges listed above. In fact, most species have the capacity to grow over a 40C (72F) range of temperatures. System parameters such as the availability of nutrients, pH, salinity, and pressure can also alter the optimum growth temperature for a particular strain of bacteria. Finally, bacteria ar
35、e often grouped according to the nutrients that the organism uses for growth and reproduction, the biochemical pathways where the organism obtains energy, or the end-product chemicals that the organism eliminates. Examples of this classification method are sulfate-reducing bacteria (SRB), acid-produ
36、cing bacteria (APB), iron-oxidizing bacteria, sulfur-oxidizing bacteria (SOB), and manganese-fixing bacteria. If bacteria are identified, they are typically given a genus and species name.7-10These names occur together as two words, the first referring to the genus and the second to the species. As
37、an example, Desulfovibrio desulfuricans is a specific name of one type of SRB. Often, names of bacteria are intended to be descriptive of the main characteristic of the organism. Thus, the Desulfovibrio desulfuricans is a bacterium that is in the shape of a curved rod that acts to remove sulfate by
38、reduction to sulfide. Sulfate-Reducing Bacteria SRB are one of the most common and problematic type of bacteria in oil and gas field systems.11-16Although strictly anaerobic, SRB can persist and survive in systems containing dissolved oxygen.17Typically, they are found in quiescent water in dead leg
39、s of pipes, ratholes of wells, and under deposits of scale and other bacteria. They are also found as free-floating (planktonic) bacteria in turbulent waters. SRB tolerate a wide pH range of 5 to 9.5, but some oilfield brines reportedly are too saline to be conducive to active growth.18Most strains
40、of SRB grow best at temperatures between 25 and 35C (77 and 95F), but a few thermophilic strains function at temperatures higher than 60C (140F).4,19,20Desulfovibrio, Desulfobacter, and Desulfotomaculum are three common genera of SRB. Other genera have also been identified.17While SRB often differ i
41、n appearance or in the substances they metabolize, they all oxidize organic compounds to organic acids or CO2by reducing sulfate ions to sulfide ions through anaerobic respiration. In the absence of sulfate ions, SRB can also respire through reduction of sulfite and other sulfur-containing ions. Sul
42、fide ions that are produced during the respiration process can react with dissolved iron NACE International 5 to produce black deposits of iron sulfide, or with hydrogen ions to form poisonous hydrogen sulfide (H2S). The presence of either iron sulfide or H2S in field systems causes operational prob
43、lems (see section on Problems Caused by Oil and Gas Field Bacteria). When steel corrodes, a layer of atomic hydrogen builds up on the cathodic surface. If the hydrogen is not removed, it polarizes the surface and causes the corrosion rate to decrease. Using hydrogen in their anaerobic respiration pr
44、ocess, SRB remove the atomic hydrogen from the surface, causing the cathodic surface to depolarize and increasing the rate of corrosion.1,21-23As a result, pit formation is accelerated. This corrosion process has been termed microbiologically influenced corrosion (MIC) and is the subject of many exc
45、ellent reviews (see annotated bibliography for further information). Iron-Oxidizing Bacteria Iron-oxidizing bacteria are also known as iron-depositing bacteria and iron-related bacteria (IRB). These microaerobic bacteria belong to one of the genera Gallionella, Siderocapsa, Sphaerotilus, Crenothrix,
46、 Leptothrix, or Clonothrix. Iron-oxidizing bacteria are filamentous bacteria, usually found in hemispherical mounds, termed tubercles, over pits on steel surfaces.1,21The presence of rust-colored water and yellow-orange slime deposits usually suggest the presence of oxygen or oxidizing chemicals; ho
47、wever, these symptoms are sometimes caused by iron-oxidizing bacteria. In oilfield systems, iron-oxidizing bacteria are reportedly found in open ponds, supply wells, filters, lines, equipment, and in injection wells.24Iron-oxidizing bacteria derive their name from the fact that they respire by oxidi
48、zing iron(II) to iron(III). Many of these organisms can also derive energy by oxidizing manganese(II) ions to manganese(III) ions. In oilfield brines, the iron(III) forms ferric hydroxide and ferric chloride that accumulate in the tubercles (see Figure 1). In addition to being aggressively corrosive
49、 to austenitic stainless steel (SS) as well as carbon steel (CS), the ferric chloride deposits on the tubercle and establishes an anaerobic environment in which SRB can thrive. FIGURE 1: Reactions possible under tubercles created by iron-oxidizing bacteria.1 Acid-Producing Bacteria Many bacteria produce organic and inorganic acids during their metabolism. Examples of APB are the anaerobic Clostridium aceticu
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