生物竞争抑制作用对渤海J油田微生物降解驱油聚合物功能的影响

【目的】揭示可降解驱油用聚合物的油藏内源微生物群落组成,分析生物竞争抑制作用(bio-competitive exclusion,BCX)对微生物聚合物降解功能的影响。【方法】通过室内培养实验,观察BCX对驱油用聚合物黏度的影响,随后借助高通量测序技术分析渤海J油田中与聚合物降解相关的微生物菌种,并探寻样本中丰度较高的聚合物降解功能基因─酰胺酶、加氧酶、硫化氢生成酶基因。之后,比对测序结果,采用实时荧光定量法验证上述功能基因在样本之间的含量差异,最后进一步注释携带上述功能基因的微生物群落组成。【结果】BCX可有效地延缓驱油聚合物黏度的损失。油田中与聚合物降解相关的微生物有Acetomicrobium、 Tepidiphilus、Thermoanaerobacter、Fervidobacterium、Ralstonia、Halomonas、Roseovarius、Deferribacteraceae和Comamonadaceae等9类菌种。高通量测序分析得到样本中BCX可显著下调丰度的聚合物降解功能基因共计有7种,其中酰胺酶基因ansB、加氧酶基因ssuD在样本之间的含量经定量验证,发现...     

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。     

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。     

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。     

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.     

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。     

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。     

大庆油田微生物采油现场试验进展

本文介绍近十几年以来大庆油田利用具有产气、降解原油、产生物表面活性剂及堵调性能的菌剂,通过地下发酵,开展微生物采油现场试验取得的进展.分析了该项技术适用的油藏条件和应用特点.截止到2012年底,应用微生物采油技术增产原油达12×104 t.其中微生物单井吞吐518口,累计增油6.3×104t,实施微生物驱和调驱项目10项(45个井组),累计增油5.7×104 t,为大庆油田稳产发挥了重要作用.     

模拟油藏条件下内源微生物群落空间分布规律

【背景】油藏内源微生物群落是开展内源微生物驱油技术的物质基础,由于油藏多孔介质取样技术难度大、成本高,实施内源微生物驱油后从注入端到产出端多孔介质中的内源微生物空间分布规律尚不明确。【目的】通过室内长岩心连续驱替实验模拟油藏内源微生物驱油过程,分析实施后不同空间位点油砂上吸附的内源微生物群落结构,揭示从注入端到产出端内源微生物群落的空间分布规律。【方法】借助高通量测序技术及荧光定量PCR技术解析不同空间位点油砂原位微生物群落信息。【结果】注入端到产出端不同空间位点生态环境的差异及菌属间的相互作用造成油藏内源微生物群落空间分布差异,存在明显的好氧、厌氧空间演替变化规律。岩心前端主要存在一些好氧类的产生物表面活性剂类微生物如假单胞菌属,岩心中部主要存在兼性和厌氧类的微生物如地芽孢杆菌、厌氧杆菌属,岩心末端主要分布严格厌氧类细菌和产甲烷古菌,厌氧类微生物代谢产生的H2、CO2和乙酸分子可以为产甲烷古菌提供代谢底物。【结论】通过室内物模油砂研究,首次明确了内源微生物群落在多孔介质中从注入端到产出端的空间分布规律,证实油藏内源微生物的好氧、厌氧空间接替分布规律,深化了对油藏内源微生物的认识。     

Polymers for enhanced oil recovery: fundamentals and selection criteria

With a rising population, the demand for energy has increased over the years. As per the projections, both fossil fuel and renewables will remain as major energy source (678 quadrillion BTU) till 2030 with fossil fuel contributing 78% of total energy consumption. Hence, attempts are continuously made to make fossil fuel production more sustainable and cheaper. From the past 40 years, polymer flooding has been carried out in marginal oil fields and have proved to be successful in many cases. The common expectation from polymer flooding is to obtain 50% ultimate recovery with 15 to 20% incremental recovery over secondary water flooding. Both naturally derived polymers like xanthan gum and synthetic polymers like partially hydrolyzed polyacrylamide (HPAM) have been used for this purpose. Earlier laboratory and field trials revealed that salinity and temperature are the major issues with the synthetic polymers that lead to polymer degradation and adsorption on the rock surface. Microbial degradation and concentration are major issues with naturally derived polymers leading to loss of viscosity and pore throat plugging. Earlier studies also revealed that polymer flooding is successful in the fields where oil viscosity is quite higher (up to 126 cp) than injection water due to improvement in mobility ratio during polymer flooding. The largest successful polymer flood was reported in China in 1990 where both synthetic and naturally derived polymers were used in nearly 20 projects. The implementation of these projects provides valuable suggestions for further improving the available processes in future. This paper examines the selection criteria of polymer, field characteristics that support polymer floods and recommendation to design a large producing polymer flooding.     

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。     

Application of microbial enhanced oil recovery technique to a Turkish heavy oil

Summary Microbial enhance oil recovery utilizes microorganisms and their metabolic products to improve the recovery of crude oil from reservoir rocks. In this study an anaerobic bacterium, Clostridium acetobutylicum was injected into a one-dimensional model reservoir containing a Turkish heavy oil (Raman oil) at 38° C. This injection was followed by water flooding after a suitable shut-in period. Comparison of oil recovery results of pure water flooding runs with experiments in which bacterial concentration and shut-in periods were varied indicated increases in oil recovery of about 12% of the original oil in place. This increase was attributed to changes in the viscosity and pH of the crude oil.Offprint requests to: T. Mehmetoglu     

Study on distribution of reservoir endogenous microbe and oil displacement mechanism

In order to research oil displacement mechanism by indigenous microbial communities under reservoir conditions, indigenous microbial flooding experiments using the endogenous mixed bacterium from Shengli Oilfield were carried out. Through microscopic simulation visual model, observation and analysis of distribution and flow of the remaining oil in the process of water flooding and microbial oil displacement were conducted under high temperature and high pressure conditions. Research has shown that compared with atmospheric conditions, the growth of the microorganism metabolism and attenuation is slowly under high pressure conditions, and the existence of the porous medium for microbial provides good adhesion, also makes its growth cycle extension. The microbial activities can effectively launch all kinds of residual oil, and can together with metabolites, enter the blind holes off which water flooding, polymer flooding and gas flooding can’t sweep, then swap out remaining oil, increase liquidity of the crude oil and remarkably improve oil displacement effect.     

青海油田微生物采油技术研究

从青海油田地层水中分离培养出4株微生物菌种,对其进行了耐温性、耐盐性等进行了探讨,分析了微生物处理前后原油组份及物性变化情况,并采用岩芯流动试验探讨了微生物的驱油效果。结果表明,这几种微生物菌种均能适应青海油田温度及高矿化度地层环境,作用于原油后对原油中的长链饱和烃类物质有较好的降解作用,能使其分子链变短,并产生有机酸或石油羧酸盐类表面活性剂等低分子物质,使原油的粘度、凝点及蜡含量均出现明显的下降,改善原油的流动性能。提高石油采收率。2口井的现场试验证明,微生物采油具有良好的提高石油采收率的效果和清蜡减阻效果。     

Evaluation of Slime-Producing Bacteria in Oil Field Core Flood Experiments

Epifluorescence microscopy and carbohydrate determinations indicated that the decrease in permeability of oil reservoir sand to reclaimed sewage water was partially the result of biological plugging. Filtration and biocide addition studies demonstrated that the increase in bacterial densities and slime concentrations in flooded oil field cores appeared to be due to both deposition from the reclaimed water and in situ microbial growth and slime production. Although these biological components increased throughout the cores during flooding, the region where the water entered the core exhibited the highest cell densities and slime concentrations. The approach described in this report should be useful in predicting the potential of a water source to induce biological plugging of oil reservoir sand.     

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.     

Alteration of the growth rate and lag time of Leuconostoc mesenteroides NRRL-B523.

Bacterial profile modification is an important enhanced oil recovery technique used to direct injected water into a reservoir's low permeability zone containing trapped crude oil. During water flooding, the use of bacteria to plug the high permeability water zone and divert flow into the oil-bearing low-permeability zone will have a significant economic impact. However, during the field implementation of bacterial profile modification, the rapid growth of bacteria near the injection well bore may hinder the subsequent injection of growth media so that profile modification of the reservoir occurs only in the immediate vicinity of the well bore. By slowing the growth rate and prolonging the lag phase, the onset of pore-space plugging may be delayed and the biologically active zone extended deep into the reservoir. High substrate loading, high pH values, and the addition of the growth inhibitors sodium dodecylsulfate and sodium benzoate have been used in combination to alter the growth characteristics of Leuconostoc mesenteroides NRRL-B523 grown in batch conditions. The highest sucrose concentration used in these studies, 500 g/L, produced lag times 12-fold greater than the slowest lag times achieved at low sucrose concentrations. When L. mesenteroides was grown in media containing 500 g/L sucrose, an alkaline pH value threshold was found above which bacteria did not grow. At this threshold pH value of 8.1, an average lag time of 200 h was observed. Increasing the concentration of sodium benzoate had no effect on lag time, but reduced the growth rate until the threshold concentration of 0.6%, above which bacteria did not grow. Last, it was found that a solution of 0.075 mM sodium dodecylsulfate in media containing 15 g/L sucrose completely inhibited bacterial growth.