油田注水层杀菌解堵的综合处理

在注水采油过程中,微生物对注水油层的堵塞问题在50年代初就引起了注意。一些研究工作者在室内模拟试验条件下证实,注入水中的微生物菌体是造成地层堵塞的重要因     

微生物提高石油采收率(I)

原油深藏于地下,并不呈油河的状态,而是分散于含油岩层岩石的毛细孔隙中。当钻井至油层时,分散的原油在地层原始压力的躯动下汇集起来,从采油井中喷至地表。依靠地层天然能量（自喷）采油称为一次采油。随着能量的消耗,自喷的原油逐渐减少,乃至停止。为维持地层压力,广泛采用了注水驱油和抽吸并用的技术,称为二次采油。即使如此,也只能采出油层原始储油量的１／３左右,大部分原油仍滞留在荷油岩中,或位于水驱的扫油面积之外,有待于研究开发新的采油技术去索取。微生物提高石油采收率（ＭＥＯＲ）就是其中引起注意的高新技术之一…     

高温高盐油藏微生物驱技术研究

青海油田跃进油区尕斯油藏中浅层地层平均温度65℃,地层水矿化度高达10％～17％。为探索微生物采油的可行性,对尕斯油藏地层水进行微生物种类及数量的鉴定,在分析地层水组分的基础上,设计两种激活体系,并考证激活剂对本源微生物的激活效果以及作用原油的效果。在临近相同油藏条件的地层水中筛选到一株耐高温高矿化度的石油降解菌,该菌能够产生表面活性剂,降低菌液的表面张力,改变岩石的润湿性,从而确定出适于尕斯油藏的微生物采油方式。     

油层注水杀菌、解堵的模拟试验

我国玉门老君庙油田许多注水井受细菌危害而堵塞。胜利油田三区油层因注入水中含SO~(2-)_4和硫酸盐还原菌,注水进入地层后SO~(2-)_4完全消失,菌体大量增殖,对注水井造成危害,所以研究把注入水中的微生物基本杀灭,对维持稳定的注水能力、增加原油产量具有重要的意义。本文报道这方面的研究结果。     

渤海N油田油藏内源微生物群落结构分析

利用变性梯度凝胶电泳(denaturing gradient gel electrophoresis,DGGE)技术分析渤海N油田注水和未注水油藏中细菌和古菌群落结构组成及分布特征,试分析注水过程对油藏微生物群落丰度和种群的影响,为开展目标油田本源微生物采油试验提供技术支持。结果显示,注水采油井中细菌丰度和种类明显高于未注水采油井,其中注水采油井中的细菌主要为固氮螺菌属(Azospira sp.)、铜绿假单胞菌(Pseudomonas sp.)、陶厄氏菌属(Thauera sp.);注水井古菌的丰度和种类与未注水井也存在一定差异,主要为热自养甲烷热杆菌(Methanothermobacter thermautotrophicus)、甲烷鬃毛菌属(Methanosaeta)、嗜泉古菌(Crenarchaeote)。注水井和未注水井中的细菌、古菌种类分布有限,但丰度较高,主要为提高原油采收率有益的采油菌种,显示该区块具备开展本源微生物微生物采油技术实施的条件。     

胜利油藏不同时间细菌群落结构的比较

利用聚合酶链式反应-变性梯度凝胶电泳(PCR-DGGE)和构建16S rRNA基因克隆文库2种方法,对孤岛油田两口井(注水井G和采油井L)在相距9个月的2个时间点(A和B)所采集样品的细菌群落结构进行了比较。DGGE图谱聚类分析表明注水井在2个时间点的微生物群落结构相似性为48.1%,而采油井的相似性只有28.7%。16S rRNA基因克隆文库结果表明,A时间点样品G中的优势菌群为Betaproteobacteria、Gammaproteobacteria,还有Deferribacteres、Firmicutes、Bacteroidetes等;而样品L中,Gammaproteobacteria中的Moraxellaceae含量达到97%。B时间点G中除了优势菌Betaproteobacteria之外,Deferribacteres的数量显著增加,成为优势菌;而L在B时间点优势菌除Gammaproteobacteria外,还有Betaproteobacteria和Firmicutes。采油井中的微生物群落结构随时间发生了显著改变,而注水井变化不显著。这一结果部分揭示了微生物采油过程中地层微生物群落的变化规律,有助于进一步阐明微生物驱油的机理。     

高温油藏内源微生物及其提高采收率潜力研究

大港孔店油田油藏特征、流体和微生物性质分析结果表明, 属于高温生态环境, 地层水矿化度较低, 氮、磷浓度低, 而且缺乏电子受体, 主要的有机物来源是油气。油田采用经过除油处理的油藏产出水回注方式开发, 油层中存在的微生物类型主要是厌氧嗜热菌, 包括发酵菌(102个/mL~105个/mL), 产甲烷菌(103个/mL); 好氧菌主要存在于注水井周围。硫酸盐还原菌(SRB)还原速率0.002 mg S2-/(L·d) ~18.9 mg S2-/(L·d), 产甲烷菌产甲烷速率0.012 mgCH4/(L·d)~16.2 mgCH4/(L·d)。好氧菌能够氧化油形成生物质, 部分氧化产物为挥发性脂肪酸和表面活性剂。产甲烷菌在油氧化菌液体培养基中产生CH4, CO2为好氧微生物和厌氧微生物的共同代谢产物。这些产物具有提高原油流动性的作用。用示踪剂研究了注入水渗流方向。通过综合分析, 油藏微生物具有较大的潜力, 基于激活油层菌的提高采收率方法在该油田是可行的。     

用PCR-DGGE 方法分析渤海原油降解过程微生物群落结构变化

针对渤海油田原油粘度大、含水上升快、常规措施作用不明显的特点, 采用微生物采油技术开展提高稠油采收率研究。通过室内物理模拟实验, 结合变性梯度凝胶电泳(Denature Gradient Gel Electrophoresis, DGGE) 技术及原油粘度测定分析研究均质、非均质岩心驱替前后稠油采收率变化、微生物群落丰度结构变化、原油理化性质变化, 尝试分析微生物提高稠油采收率机理。物模结果表明: 微生物采油体系能够有效提高稠油采收率, 在均质岩心和非均质岩心驱替中, 微生物体系可分别提高采收率14.4%、29.4%; DGGE 结果显示: 微生物体系出口端丰度明显高于注入端;原油粘度测定显示: 出口端原油粘度明显下降。三者结合说明微生物体系能够利用稠油作为碳源, 在地层环境中生长,菌种在地层中有较强的适应性, 同时能够降低稠油粘度, 提高其采收率。     

采油微生物在微驱过程中的生长、运移及分布规律

[目的]深入了解现场微生物驱油机理、效果评价标准及影响因素.[方法]结合现场微生物驱油过程产出液的跟踪监测及室内物模实验对微生物在地层中的生长繁殖、运移及分布规律进行研究.[结果]结果表明,通过从水井注入的外源微生物在油藏中能够有效生长繁殖,而且注入的营养液也能够激活内源微生物,但由于地层渗透率及营养液浓度的影响,产出液菌浓要比注入菌浓低1-2个数量级;葡萄糖的快速降解以及地层对微生物的过滤及吸附作用使大量的微生物停留在近井地带,仅有部分微生物能够从生产井采出,而且其运移速度要比营养液慢.[结论]地层渗透率和产出液中营养物浓度是影响微生物数量及分布的两个关键因素,现场微生物驱油产出液中的菌浓一般很难达到106个/mL以上,该研究结果对微生物驱油技术的发展和应用具有重要意义.     

科技信息

1987—1988年微生物提高采油的概况1987年约有6项微生物提高采油的规划开始执行或继续执行,而1988年只有澳大利亚公布了一项新的大规模的试验规划。微生物提高采油是将微生物注入井下提高产油量的一种方法,该法的许多支持者长期地     

Anaerobic treatment of sulphate-containing waste streams

Sulphate-containing wastewaters from the paper and board industry, molasses-based fermentation industries and edible oil refineries present difficulties during anaerobic treatment, leading to problems of toxicity, reduction in methane yield, odour and corrosion. The microbiology and biochemistry of dissimilatory sulphate reduction are reviewed in order to illustrate the potential competition between sulphate reducers and other anaerobes involved in the sequential anaerobic mineralisation process. The theoretical considerations which influence the outcome of competition between sulphate reducers and fermentative, syntrophic, homoacetogenic and methanogenic bacteria are discussed. The actual outcome, under the varying influent organic composition and strength and sulfate concentrations which prevail during digestion of industrial wastewaters, may be quite different to that predicted by thermodynamic or kinetic considerations. The factors governing competitive interactions between SRB and other anaerobes involved in methanogenesis is discussed in the context of literature data on sulphate wastewater treatment and with particular reference to laboratory and full-scale digestion of citric acid production wastewater.     

Distribution of thermophilic marine sulfate reducers in north sea oil field waters and oil reservoirs

The distribution of thermophilic marine sulfate reducers in produced oil reservoir waters from the Gullfaks oil field in the Norwegian sector of the North Sea was investigated by using enrichment cultures and genus-specific fluorescent antibodies produced against the genera Archaeoglobus, Desulfotomaculum, and Thermodesulforhabdus. The thermophilic marine sulfate reducers in this environment could mainly be classified as species belonging to the genera Archaeoglobus and Thermodesulforhabdus. In addition, some unidentified sulfate reducers were present. Culturable thermophilic Desulfotomaculum strains were not detected. Specific strains of thermophilic sulfate reducers inhabited different parts of the oil reservoir. No correlation between the duration of seawater injection and the numbers of thermophilic sulfate reducers in the produced waters was observed. Neither was there any correlation between the concentration of hydrogen sulfide and the numbers of thermophilic sulfate reducers. The results indicate that thermophilic and hyperthermophilic sulfate reducers are indigenous to North Sea oil field reservoirs and that they belong to a deep subterranean biosphere.     

Some aspects on the role of bacteria in deep water ecosystems

Summary Some remarks on the role of bacteria in deep lakes will be presented with an emphasis on their functioning in the carbon cycle in such ecosystems.The metabolic intensity of most lakes is regulated to a large extent at the primary producer level. Aerobic and anaerobic decomposition by heterotrophic bacteria of the unstable ultimate products of photosynthesis results in the production of carbon dioxide and methane. Bacterial growth occurs at the expense of energy released by the flow of electrons from donors to acceptors. Typical electron acceptors for bacterially mediated reactions are oxygen, nitrate, sulphate and carbon dioxide. When oxygen is used as electron acceptor, the highest amount of energy is released, while the lowest is released when carbon dioxide is used. These reactions are mediated biologically, and the chemical reaction sequence is paralleled by an ecological succession of microorganisms: aerobic heterotrophs, denitrifiers, fermenting bacteria, sulphate reducers, and methane producers. The presence of oxygen is inhibitory to the organisms mediating the last reactions (STUMM, 1966; McCARTY, 1972), and this explains the succession of micro-organisms concomittant with the decrease in redox potential.Both labile and refractory fractions of the pelagial dissolved organic matter can directly be utilized largely by heterotrophic bacteria. At the onset of the summer stratification of Lake Vechten a high concentration (numbers 10⁹ bact/L) of heterotrophic bacteria has been detected in the lower water layers (CAPPENBERG, 1972). The reason for this increase may be a release of nutrients from the mud. During stratification the water layers above the mud become anaerobic owing to the metabolic activity of the bacterial flora and the chemical oxygen demand of the mud. In summer time the highest numbers of heterotrophic bacteria are found in the metalimnion, where organic matter accumulates due to a lower relative rate of sedimentation caused by an increase in viscosity and density.Furthermore it was found that sulphate-reducing bacteria which are capable of reducing sulphates to sulphides using sulphate as terminal electron acceptor, were observed in the hypolimnion only at the time of maximal stratification. During stagnation, gradually decreasing sulphate concentrations are found in the hypolimnion, correlated with increaseing cell numbers of sulphate reducers. As no sulphate could be detected in the mud of Lake Vechten as well, we may conclude that the sulphate concentration limits the number of these bacteria, as can be predicted for similar aquatic environments.Usually the sulphate reducers are found in bottom deposits and are an important group of bacteria of the non-methanogenic populations in mud. Summarizing the biological methane production and its subsequent oxidation by methane-oxidizing bacteria, we may conclude that these processes can be important factors functioning in the carbon cycle in deep fresh-water ecosystems.     

A case study for late Archean and Proterozoic biogeochemical iron‐ and sulphur cycling in a modern habitat—the Arvadi Spring

As a consequence of Earth's surface oxygenation, ocean geochemistry changed from ferruginous (iron(II)‐rich) into more complex ferro‐euxinic (iron(II)‐sulphide‐rich) conditions during the Paleoproterozoic. This transition must have had profound implications for the Proterozoic microbial community that existed within the ocean water and bottom sediment; in particular, iron‐oxidizing bacteria likely had to compete with emerging sulphur‐metabolizers. However, the nature of their coexistence and interaction remains speculative. Here, we present geochemical and microbiological data from the Arvadi Spring in the eastern Swiss Alps, a modern model habitat for ferro‐euxinic transition zones in late Archean and Proterozoic oceans during high‐oxygen intervals, which enables us to reconstruct the microbial community structure in respective settings for this geological era. The spring water is oxygen‐saturated but still contains relatively elevated concentrations of dissolved iron(II) (17.2 ± 2.8 μM) and sulphide (2.5 ± 0.2 μM) with simultaneously high concentrations of sulphate (8.3 ± 0.04 mM). Solids consisting of quartz, calcite, dolomite and iron(III) oxyhydroxide minerals as well as sulphur‐containing particles, presumably elemental S⁰, cover the spring sediment. Cultivation‐based most probable number counts revealed microaerophilic iron(II)‐oxidizers and sulphide‐oxidizers to represent the largest fraction of iron‐ and sulphur‐metabolizers in the spring, coexisting with less abundant iron(III)‐reducers, sulphate‐reducers and phototrophic and nitrate‐reducing iron(II)‐oxidizers. 16S rRNA gene 454 pyrosequencing showed sulphide‐oxidizing Thiothrix species to be the dominating genus, supporting the results from our cultivation‐based assessment. Collectively, our results suggest that anaerobic and microaerophilic iron‐ and sulphur‐metabolizers could have coexisted in oxygenated ferro‐sulphidic transition zones of late Archean and Proterozoic oceans, where they would have sustained continuous cycling of iron and sulphur compounds.     

Regional distribution of water and glycosaminoglycan in immature articular cartilage

The distribution of water and glycosaminoglucan in different functional regions of bovine immature articular cartilage were studied. There was always more water in each articulating than in the corresponding growin zone, but there was less water in both zones in the areas of maximum contact. There was more hyaluronate and much more keratan sulphate in the articulating areas of maximum contact than in the minimum contact areas. In the growing zone the distribution of these two glycosaminoglycans did not vary as significantly but there was slightly more keratan sulphate in the area of maximum contact. Regional variations in chondroitin sulphate were also present although not as striking as those of keratan sulphate. The results suggest that some keratan sulphate may be synthesized as reaction to load.     

Bacteria Contribute to Sediment Nutrient Release and Reflect Progressed Eutrophication-Driven Hypoxia in an Organic-Rich Continental Sea

In the sedimental organic matter of eutrophic continental seas, such as the largest dead zone in the world, the Baltic Sea, bacteria may directly participate in nutrient release by mineralizing organic matter or indirectly by altering the sediment’s ability to retain nutrients. Here, we present a case study of a hypoxic sea, which receives riverine nutrient loading and in which microbe-mediated vicious cycles of nutrients prevail. We showed that bacterial communities changed along the horizontal loading and vertical mineralization gradients in the Gulf of Finland of the Baltic Sea, using multivariate statistics of terminal restriction fragments and sediment chemical, spatial and other properties of the sampling sites. The change was mainly explained by concentrations of organic carbon, nitrogen and phosphorus, which showed strong positive correlation with Flavobacteria, Sphingobacteria, Alphaproteobacteria and Gammaproteobacteria. These bacteria predominated in the most organic-rich coastal surface sediments overlain by oxic bottom water, whereas sulphate-reducing bacteria, particularly the genus Desulfobacula, prevailed in the reduced organic-rich surface sediments in the open sea. They correlated positively with organic nitrogen and phosphorus, as well as manganese oxides. These relationships suggest that the bacterial groups participated in the aerobic and anaerobic degradation of organic matter and contributed to nutrient cycling. The high abundance of sulphate reducers in the surficial sediment layers reflects the persistence of eutrophication-induced hypoxia causing ecosystem-level changes in the Baltic Sea. The sulphate reducers began to decrease below depths of 20 cm, where members of the family Anaerolineaceae (phylum Chloroflexi) increased, possibly taking part in terminal mineralization processes. Our study provides valuable information on how organic loading affects sediment bacterial community compositions, which consequently may maintain active nutrient recycling. This information is needed to improve our understanding on nutrient cycling in shallow seas where the dead zones are continuously spreading worldwide.     

Seasonal shifts in community composition and proteome expression in a sulphur-cycling cyanobacterial mat

Seasonal changes in light and physicochemical conditions have strong impacts on cyanobacteria, but how they affect community structure, metabolism, and biogeochemistry of cyanobacterial mats remains unclear. Light may be particularly influential for cyanobacterial mats exposed to sulphide by altering the balance of oxygenic photosynthesis and sulphide-driven anoxygenic photosynthesis. We studied temporal shifts in irradiance, water chemistry, and community structure and function of microbial mats in the Middle Island Sinkhole (MIS), where anoxic and sulphate-rich groundwater provides habitat for cyanobacteria that conduct both oxygenic and anoxygenic photosynthesis. Seasonal changes in light and groundwater chemistry were accompanied by shifts in bacterial community composition, with a succession of dominant cyanobacteria from Phormidium to Planktothrix, and an increase in diatoms, sulphur-oxidizing bacteria, and sulphate-reducing bacteria from summer to autumn. Differential abundance of cyanobacterial light-harvesting proteins likely reflects a physiological response of cyanobacteria to light level. Beggiatoa sulphur oxidation proteins were more abundant in autumn. Correlated abundances of taxa through time suggest interactions between sulphur oxidizers and sulphate reducers, sulphate reducers and heterotrophs, and cyanobacteria and heterotrophs. These results support the conclusion that seasonal change, including light availability, has a strong influence on community composition and biogeochemical cycling of sulphur and O₂ in cyanobacterial mats.     

Microorganisms of the carbonate petroleum reservoir 302 of the Romashkinskoe oilfield and their biotechnological potential

Diversity, geochemical activity, and biotechnological potential of the microorganisms from oil bed 302 of the Romashkinskoe oilfield (Tatarstan, Russia) are reported. The microbial community contained almost no aerobic microorganisms. Sulfate-reducing (10³?10⁶ cells/mL) and fermentative bacteria (10²?10⁵ cells/mL) predominated in the oilfield. Sulfate reduction was the predominant process in formation water with the rates up to 26.6 μg S^2?L/day. The number of methanogens and methanogenesis rate in formation water did not exceed 10⁴ cells/mL and 8.19 μg CH₄ L/day, respectively. Analysis of the 16S rRNA gene clone library revealed the sequences of denitrifying bacteria of the genera Sulfurimonas and Thauera. The oil recovery technique combining the stimulation of fermentative bacteria and suppression of sulfate reducers in the oilfield was proposed for development of the bed 302. Fermentative bacteria could be activated by the traditional method, i.e., injection of molasses and nitrogen and phosphorus mineral salts through the injection wells. Introduction of high concentrations of nitrate will activate the growth of denitrifying bacteria, suppress the growth of sulfidogenic bacteria, and result in decreased sulfide concentration in formation water. The proposed biotechnology is technologically simple and environmentally friendly.     

DsrL mediates electron transfer between NADH and rDsrAB in Allochromatium vinosum

Dissimilatory sulphite reductase DsrAB occurs in sulphate/sulphite-reducing prokaryotes, in sulphur disproportionators and also in sulphur oxidizers, where it functions in reverse. Predictions of physiological traits in metagenomic studies relying on the presence of dsrAB, other dsr genes or combinations thereof suffer from the lack of information on crucial Dsr proteins. The iron–sulphur flavoprotein DsrL is an example of this group. It has a documented essential function during sulphur oxidation and was recently also found in some metagenomes of probable sulphate and sulphite reducers. Here, we show that DsrL and reverse acting rDsrAB can form a complex and are copurified from the phototrophic sulphur oxidizer Allochromatium vinosum. Recombinant DsrL exhibits NAD(P)H:acceptor oxidoreductase activity with a strong preference for NADH over NADPH. In vitro, the rDsrABL complex effectively catalyses NADH-dependent sulphite reduction, which is strongly enhanced by the sulphur-binding protein DsrC. Our work reveals NAD⁺ as suitable in vivo electron acceptor for sulphur oxidation in organisms operating the rDsr pathway and points to reduced nicotinamide adenine dinucleotides as electron donors for sulphite reduction in sulphate/sulphite-reducing prokaryotes that contain DsrL. In addition, dsrL cannot be used as a marker distinguishing sulphate/sulphite reducers and sulphur oxidizers in metagenomic studies without further analysis.     

THE TOXICITY OF ZINC SULPHATE TO RAINBOW TROUT

The toxicity of zinc sulphate to rainbow trout ( Salmo gairdnerii Richardson) has been investigated in waters of different chemical and physical properties.
Zinc sulphate was less toxic to rainbow trout in hard water than in soft water; when the log concentration of zinc was plotted against log median period of survival of the fish the dose response curve was linear in a very soft water, and curvilinear in a hard water, approaching an apparent threshold concentration. Solutions of zinc sulphate containing calcium chloride were less toxic than those containing an equivalent concentration of calcium as bicarbonate.
An increase in temperature decreased the survival time of rainbow trout in solutions of zinc sulphate in a hard water, but the threshold concentration was not appreciably affected by changes in temperature.
A reduction in the dissolved oxygen concentration of the water increased the toxicity of zinc sulphate, but the effect was reduced when the fish were previously acclimatized to the lower oxygen concentration of the test.
The cause of death of fish in solutions of zinc sulphate was not by the precipitation of mucus on the gills but probably by damage to the gill epithelium.