厌氧产表面活性剂微生物提高原油采收率的研究进展

微生物强化采油(microbial enhanced oil recovery,MEOR)是近年来在国内外发展迅速的一项提高原油采收率技术。微生物在油藏中高效生产表面活性剂等驱油物质是微生物采油技术成功实施的关键之一。然而,油藏的缺/厌氧环境严重影响好氧表面活性剂产生菌在油藏原位的生存与代谢活性;油藏注空气会增加开采成本,且注入空气的作用时效和范围难以确定。因此,开发厌氧产表面活性剂菌种资源并强化其驱油效率对于提高原油采收率具有重要意义。本文综述了国内外近年来利用厌氧产表面活性剂微生物提高原油采收率的研究进展,简述了微生物厌氧产表面活性剂的相关驱油机理、菌种资源开发现状以及油藏原位驱油应用进展,并对当前的研究提出了一些思考。     

超低渗油藏微生物吞吐技术的矿场试验

【目的】通过对渭北低渗油藏内源微生物的研究,考察分离纯化的内源解烃菌产生表面活性剂和降解原油的能力、岩心驱替增油效率,同时验证其在超低渗油田单井吞吐矿场实验的应用效果,探讨微生物采油技术在超低渗油田提高采收率的工艺和可行性。【方法】采集超低渗油藏的油水样,应用油平板进行产表面活性剂解烃菌的分离,通过生理生化特性和16S r RNA基因序列分析对菌株进行种属鉴定,评价其油藏环境适应性,利用内源-外源功能微生物复配体系进行原油降解,在填砂管和岩心物模上进行驱油实验,将优化好的微生物复配体系应用于现场实施单井吞吐工艺的实验。【结果】从渭北某区块超低渗油藏的原油样品中分离得到一株铜绿假单胞菌(Pseudomonas aeruginosa),命名为WB-001。该菌株可使发酵液的表面张力降至29.04 m N/m,使渭北原油蜡质含量降至8.48%。填砂管实验表明WB-001与外源枯草芽胞杆菌OPUS-HOB-001(Bacillus subtilis)复配后,驱油效率较单纯水驱提高了9.72%;岩心驱替实验较水驱提高12.54%。微生物单井吞吐措施后,平均日产油由措施前的0.42 t增加到0.89 t,累计增油44.47 t;原油降粘率为11.70%,降凝率为9.41%,采出水表面张力降低幅度为18.93%。【结论】通过详细的室内评估和成功的矿场实验,证明微生物采油技术在超低渗油藏有一定的应用可行性,并为后续规模化应用提供了理论基础和物质基础,为超低渗油田的高效精细开发探索一条新的途径。     

内源微生物驱油及其对油藏微生物活动的影响

【目的】新疆油田六中区为典型水驱普通稠油油藏，水驱效果较差，油藏具有丰富的内源微生物，本研究通过分析内源微生物驱油对油藏微生物活动的影响，确定内源微生物驱油技术在该类油藏的应用潜力。【方法】采用高通量测序及分析化学技术，系统研究实施内源微生物驱油技术后油藏细菌群落结构组成、细菌总数和功能菌群的浓度以及采出液的流体性质，总结内源微生物驱油对油藏微生物活动的影响。【结果】现场试验注入激活剂和空气后，内源微生物被显著激活，细菌群落结构发生明显变化，细菌总数及功能菌群浓度普遍提高了2–3个数量级；各种内源微生物代谢活动显著增强，与地层流体相互作用后，原油明显被乳化，最终石油采收率提高5.2%。【结论】对于内源微生物较为丰富的水驱普通稠油油藏，内源微生物驱油技术对油藏微生物活动的影响显著，具有显著的技术优势和较大的应用潜力，微生物群落结构、功能菌群浓度及其相关代谢产物可以作为评价内源微生物驱油现场激活效果的重要指标，为其他内源微生物驱油现场试验提供技术参考。     

贝莱斯芽孢杆菌B6强化驱油机制分析及在高矿化度油藏中的应用

【目的】筛选油藏内源功能微生物并探究其驱油机理,现场试验以确定油藏内源微生物提高原油采收技术应用的工艺和技术可行性。【方法】采集英东油田样品,利用原油平板筛选驱油功能菌,评价其环境适应性并优化培养条件,通过乳化性能、降黏防蜡和烃转化能力等评估其驱油性能并探索其潜在机制,并在油田现场进行微生物强化驱油试验。【结果】从油水样品中分离到的贝莱斯芽孢杆菌(Bacillus velezensis) B6,其乳化活性指数(emulsifying activity index, EI24)值为100.00%,降黏率为97.20%,防蜡率为86.90%,表明菌株B6具有良好的乳化降黏性能,具有提高原油采收的潜力,并且能够减少原油中的重质组分而增加轻质烃类,改善原油物性,提升原油品质。进一步在英东油田、跃进油田和花土沟油田进行微生物单井吞吐和清防蜡作业,共进行62井次现场试验,累计增油1 460.36 t,平均延长洗井周期47 d,经济效益为342.50万元,投入产出比为1:4。【结论】通过室内研究和现场试验,证实内源微生物Bacillus velezensisB6具有显著提高原油采收和油井清防蜡的效果,应用潜力巨大。     

大庆聚驱后油藏微生物群落结构分析

目的:进一步研究大庆聚驱后油藏微生物种类.方法:应用T-RFLP方法比较系统地分析比较了聚驱后油藏微生物多样性,分析了与采油功能相关的主要微生物组成,初步研究了聚驱后油藏微生物分布特点及规律.结果:利用聚驱后油藏细菌群落16S rDNA构建克隆文库,共挑取了49个阳性克隆,T-RFLP分型结果,共出现21个不同类型.所得的序列在Genbank中比对的结果表明细菌克隆可分为5个类群,分属于变形杆菌、拟杆菌、脱铁杆菌、厚壁菌以及未确定分类的类群;同时构建了聚驱后油藏古菌群落16S rDNA的克隆文库,共挑取了48个阳性克隆,根据T-RF分型结果共有5个类群,构建的古菌克隆文库的12个阳性克隆分属5个不同的类群,这些克隆和产甲烷菌亲缘关系很近.结论:该研究为大庆油田本源微生物采油技术的应用提供了可靠的理论依据.     

微生物提高原油采出率的室内研究

微生物采油技术是一种提高原油采出率的卓有成效的方法。本文通过在实验室条件下模拟江苏油田韦4区块的储层情况,进行岩芯的驱替实验,对微生物采油技术在韦4区块的运用作了一些研究和评价,并得出应用结论,为该技术在现场的实验奠定了理论基础。     

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.     

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…     

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。     

聚合物驱后油藏内源微生物驱油研究与试验

我国大多数陆上主力油田已进入"双高"(高含水、高采出程度)开采阶段。为进一步提高聚合物驱后油藏的石油采收率,本研究发现了一种促进油藏内源微生物生长代谢的高效激活剂,且该激活剂已通过室内产气和物理模拟驱油实验及岩心电镜观察和454(Pyrosequencing)焦磷酸测序方法的评价。结果表明激活剂在高压容器中静置培养60 d后产气增压达到2 MPa,用量0.35 PV,浓度为1.8%(W/W)的激活剂溶液在聚合物驱后的天然岩心上石油采收率可再提高3%,并在电镜观察到岩心内部激活的内源微生物菌体及其代谢产物。现场于2011年12月在萨南南二区东块的1注4采井组开展了试验,监测到4口有效生产井的甲烷和二氧化碳气体δ13C(PDB)含量产生明显变化,与萨南南二区东块对照试验区产油量增幅35.9%,含水稳定在94%,在3年半期间阶段累计增油5 957 t,为同类油藏进一步提高石油采收率提供了一条有效途径。     

油藏微生物及其压力适应机制

目前我国油田开发主要处于高含水后期,微生物驱提高石油采收率技术(MEOR)以低成本、环境友好等独特的优势引起了石油工业界的重视。实际上,经过半个多世纪的发展,MEOR已经成为提高采收率的重要前沿技术。高压是油藏的主要环境特征,在影响油藏微生物生存与活性等方面具有重要作用。本文从油藏及其微生物的主要特征、微生物对高压环境的适应机制以及高压下微生物降解烃的代谢特征等方面进行了综述。介绍了对油藏微生物资源、群落结构、微生物在油水相中分布的认识,微生物乳化原油机制,以及微生物在油藏厌氧环境中协同代谢、受温度和压力影响的特点,并列举了MEOR的矿场应用。在高压适应机制上,微生物主要通过改变和调整细胞膜结构、增加胞内脂质组分和表达胞内特殊酶等作用来实现对压力的适应;在高压下烃降解微生物代谢速率低于常压,而且耐压菌和嗜压菌具有不同的烃降解效率。     

Response of microbial community structure to microbial plugging in a mesothermic petroleum reservoir in China

Microbial plugging, a microbial enhancement of oil recovery (MEOR) technique, has been applied in a candidate oil reservoir of Daqing Oil Field (China). The goal of this study is to monitor the survival of injected bacteria and reveal the response of microbial communities in field trial of microbial plugging through injection of selected microbial culture broth and nutrients. Culture-dependent enrichment and culture-independent 16S rDNA clone library methods were used. The results show that it was easy to activate targeted biopolymer-producing bacteria in a laboratory environment, and it was difficult for injected exogenous bacteria to survive. In addition, microbial communities in the oil reservoir also changed before and after the field trial. However, microbial communities, activated by fermentative medium for biopolymer-producing bacteria, appeared to show greater differences in the laboratory than in the natural reservoir. It was concluded that microbial populations monitoring was important to MEOR; results of response of microbial communities could provide a guide for the future field trials.     

Monitoring exogenous and indigenous bacteria by PCR-DGGE technology during the process of microbial enhanced oil recovery

A field experiment was performed to monitor changes in exogenous bacteria and to investigate the diversity of indigenous bacteria during a field trial of microbial enhanced oil recovery (MEOR). Two wells (26-195 and 27-221) were injected with three exogenous strains and then closed to allow for microbial growth and metabolism. After a waiting period, the pumps were restarted and the samples were collected. The bacterial populations of these samples were analyzed by denaturing gradient gel electrophoresis (DGGE) with PCR-amplified 16S rRNA fragments. DGGE profiles indicated that the exogenous strains were retrieved in the production water samples and indigenous strains could also be detected. After the pumps were restarted, average oil yield increased to 1.58 and 4.52 tons per day in wells 26-195 and 27-221, respectively, compared with almost no oil output before the injection of exogenous bacteria. Exogenous bacteria and indigenous bacteria contributed together to the increased oil output. Sequence analysis of the DGGE bands revealed that Proteobacteria were a major component of the predominant bacteria in both wells. Changes in the bacteria population in the reservoirs during MEOR process were monitored by molecular analysis of the 16S rRNA gene sequence. DGGE analysis was a successful approach to investigate the changes in microorganisms used for enhancing oil recovery. The feasibility of MEOR technology in the petroleum industry was also demonstrated.     

Microbially enhanced oil recovery from carbonate reservoirs

About half of the world's oil production is from carbonate formations. However, most of the research in microbially enhanced oil recovery (MEOR), a potentially important tertiary recovery technology, has focused on sandstone reservoirs because, in general, they are geologically simpler than carbonate reservoirs and easier to model in the laboratory. Carbonate formations have a wide range of pore geometries and distributions, resulting in complex flow dynamics. The low matrix permeabilities and the dual porosity characteristics of most carbonate formations, coupled with the chemistry of carbonates, have slowed implementation of enhanced oil recovery methods. A review of the data on carbonate reservoirs in Dwight's Energydata TOTL System indicated that 40% of the oil‐producing carbonate reservoirs surveyed in the United States have environmental, geological, and petrophysical conditions that would make them candidates for MEOR. A review of a number of MEOR field trials showed that rates of oil production could be increased by as much as 200%. Microbial activity in these trials was probably due to that of indigenous populations rather than the microorganisms injected for the trials. Detrimental effects such as loss of injectivity and increased souring were not reported. Based on analysis of the geology and petrophysical characteristics of carbonates, two common mechanisms of MEOR, microbial acid production and microbial gas production, are especially suited for application in carbonate reservoirs.     

油藏微生物的代谢特征与提高原油采收率技术

油藏是一个高温、高压、少氧、寡营养和封闭的极端环境,油田经过多年注水开发后,在油藏内部形成了相对稳定的微生物群落体系,这些微生物以石油烃分解为起始,形成了一个复杂的食物链,对油藏碳、硫和金属离子的元素地球化学循环起着非常重要的作用。微生物提高原油采收率技术(MEOR)是利用微生物及其代谢产物与油藏和原油发生作用来提高原油采收率的一种新技术,具有成本低、适应性强和环境友好等特点,因此有望成为未来化学驱后油藏和高含水油藏进一步提高采收率的重要手段。对油藏内源微生物及其介导的生化反应,微生物采油原理、发展历程和现场试验进行综述,并提出了未来的发展方向。     

Impact of an indigenous microbial enhanced oil recovery field trial on microbial community structure in a high pour-point oil reservoir

Based on preliminary investigation of microbial populations in a high pour-point oil reservoir, an indigenous microbial enhanced oil recovery (MEOR) field trial was carried out. The purpose of the study is to reveal the impact of the indigenous MEOR process on microbial community structure in the oil reservoir using 16Sr DNA clone library technique. The detailed monitoring results showed significant response of microbial communities during the field trial and large discrepancies of stimulated microorganisms in the laboratory and in the natural oil reservoir. More specifically, after nutrients injection, the original dominant populations of Petrobacter and Alishewanella in the production wells almost disappeared. The expected desirable population of Pseudomonas aeruginosa, determined by enrichment experiments in laboratory, was stimulated successfully in two wells of the five monitored wells. Unexpectedly, another potential population of Pseudomonas pseudoalcaligenes which were not detected in the enrichment culture in laboratory was stimulated in the other three monitored production wells. In this study, monitoring of microbial community displayed a comprehensive alteration of microbial populations during the field trial to remedy the deficiency of culture-dependent monitoring methods. The results would help to develop and apply more MEOR processes.     

Exopolysaccharide production by a genetically engineered Enterobacter cloacae strain for microbial enhanced oil recovery

Microbial enhanced oil recovery (MEOR) is a petroleum biotechnology for manipulating function and/or structure of microbial environments existing in oil reservoirs for prolonged exploitation of the largest source of energy. In this study, an Enterobacter cloacae which is capable of producing water-insoluble biopolymers at 37 °C and a thermophilic Geobacillus strain were used to construct an engineered strain for exopolysaccharide production at higher temperature. The resultant transformants, GW3-3.0, could produce exopolysaccharide up to 8.83 g l⁻¹ in molasses medium at 54 °C. This elevated temperature was within the same temperature range as that for many oil reservoirs. The transformants had stable genetic phenotype which was genetically fingerprinted by RAPD analysis. Core flooding experiments were carried out to ensure effective controlled profile for the simulation of oil recovery. The results have demonstrated that this approach has a promising application potential in MEOR.     

N52等三株采油细菌的分离鉴定

从大庆油田被原油长期污染的水和土壤样品中,分离出8株三次采油细菌。用API ATB EXPRESS菌种分析仪和16s-rDNA分析的方法,对其中3个采油效果好的菌株进行了鉴定。结果3个菌株分别为：J41阴沟肠杆菌、982和N52蜡状芽孢杆菌。     

油藏微生物群落研究的方法学

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