Progress of Microbial Enhanced Oil Recovery in Laboratory Investigation

This paper describes a simple, easy process for screening microorganisms, and introduces a laboratory simulation device and process of microbial enhanced oil recovery (MEOR) , which is a necessary research step for trial in oilfields. The MEOR mechanism and the influence of adsorption, diffusion, metabolism, nutrition, porosity, and permeability are analyzed. The research indicates that different microbes have different efficiencies in EOR and that different culture types play different roles in EOR. The effect of syrup is better than that of glucose, and larger porosity is favorable to the reproduction and growth of microbes, thereby improving the oil recovery. Using crude oil as a single carbon source is more appreciable because of the decrease in cost of oil recovery. At the end of this paper, the development of polymerase chain reaction (PCR) for the future is discussed.

Research on the Jilin Oilfield Field Trials of Microbial Enhanced Oil Recovery

This paper describes the experience of Jilin oilfield trials for Microbial Enhanced Oil Recovery (MEOR). A new technique to identify microbes with DNA for MEOR has been established, and useful microbes selected for use in field trials. Behaviors of bacteria activated in the reservoir, oil recovery and water cut, and the viscosity of crude oil produced through huff & puff testing and flooding with molasses-injection tests, have been investigated in situ. CJF-002, which produces biopolysaccharide, is the best among the microbes used for field trials, as it can use molasses as nutrient and produce a small quantity of CO2 and a mass of water-insoluble biopolymer. The metabolic behavior in the reservoir showed that CJF-002 had a good potentiality for MEOR.

Relationship between Microbial Community Characteristics and Flooding Efficiency in Microbial Enhanced Oil Recovery

Microbial enhanced oil recovery (MEOR) is the research focus in the field of energy development as an environmentally friendly and low cost technology. MEOR can bes divided into indigenous microbial oil recovery and exogenous microbial oil recovery. The ultimate goal of indigenous microbial flooding is to enhance oil recovery via stimulation of specific indigenous microorganisms by injecting optimal nutrients. For studying the specific rule to activate the indigenous community during the long-term injection period, a series of indigenous displacement flooding experiments were carried out by using the long-core physical simulation test. The experimental results have shown that the movement of nutrients components (i.e., carbon/nitrogen/phosphorus) differed from the consumption of them. Moreover, there was a positive relationship between the nutrients concentration and bacteria concentration once observed in the produced fluid. And the trend of concentration of acetic acid was consistent with that of methanogens. When adding same activators, the impacts of selective activators to stimulate the indigenous microorganisms became worse along with the injection period, which led to less oil recovery efficiency.

Study of a plugging microbial consortium using crude oil as sole carbon source

A microbial consortium named Y4 capable of producing biopolymers was isolated from petroleum-contaminated soil in the Dagang Oilfield, China. It includes four bacterial strains： Y4-1 （Paenibacillus sp.）, Y4-2 （Actinomadura sp.）, Y4-3 （Uncultured bacterium clone） and Y4-4 （Brevibacillus sp.）. The optimal conditions for the growth of the consortium Y4 were as follows： temperature about 46 ℃, pH about 7.0 and salinity about 20.0 g/L. The major metabolites were analyzed with gas chromatographymass spectrometry （GC-MS）. A comparison was made between individual strains and the microbial consortium for biopolymer production in different treatment processes. The experimental results showed that the microbial consortium Y4 could produce more biopolymers than individual strains, and the reason might be attributed to the synergetic action of strains. The biopolymers were observed with optical and electron microscopes and analyzed by paper chromatography. It was found that the biopolymers produced by the microbial consortium Y4 were insoluble in water and were of reticular structure, and it was concluded that the biopolymers were cellulose. Through a series of simulation experiments with sand cores, it was found that the microbial consortium Y4 could reduce the permeability of reservoir beds, and improve the efficiency of water flooding by growing biomass and producing biopolymers. The oil recovery was enhanced by 3.5% on average. The results indicated that the consortium Y4 could be used in microbial enhanced oil recovery and play an important role in bioremediation of oil polluted environments.

微生物提高油藏原油采收率进展

文章从油藏中普遍存在的采油微生物类群及其驱油机制、微生物采油技术的矿场应用、采油微生物的响应等方面对油藏微生物及其提高原油采收率进展进行综述.同时从营养剂在油藏储层中的分布、油藏环境下微生物生长代谢活性、油藏微生物定向调控等方面阐述了微生物采油技术发展的基础问题.

反硝化产气温和食酸菌G21及其在油田生产中的应用潜力

以反硝化产气菌在油田生产中的潜在应用为出发点,从油田产出液中分离到一株兼性厌氧反硝化产气菌G21,对菌株G21进行了16S rRNA基因和反硝化功能基因分析,并基于产气效果对最佳碳源及碳氮比进行优化,测定产生气体的组分,从G21与油藏产出液互配性角度探究了G21在油田生产中的应用潜力。结果表明:菌株G21与Acidovorax temperans PHL的16S rRNA基因相似性达到99.36%,属于温和食酸菌;菌株G21含有膜结合硝酸盐还原酶(Nar)、周质硝酸盐还原酶(Nap)、亚硝酸盐还原酶(Nir)、一氧化氮还原酶(Nor)和氧化亚氮还原酶(Nos)的编码基因;气体组分分析结果证实,菌株能够将硝酸盐氮还原为氧化亚氮和N_(2);糖类是其反硝化产气的最佳碳源,碳氮比为5∶1时(葡萄糖5000 mg/L(以化学需氧量COD计)、NaNO_(3)-N 1000 mg/L),产气量(气液比)达到1∶1;在油藏产出液中,G21产气性能良好,且能压制硫酸盐还原菌的生长。可见,反硝化产气温和食酸菌G21在防控油藏硫酸盐还原菌和产气提高原油采收率方面具有一定的应用潜力。

Brief Review on MEOR Technology

As one of the main oil production countries, China pays great attention to the study and application of new technologies to enhance oil recovery. Microbial enhanced oil recovery (MEOR), an advanced technology, is one of the focuses. This paper gives a brief review on the history of the MEOR development and of laboratory-based and field application programmes. Mechanisms of MEOR are presented. Microorganisms can produce gases, acids, surfactants, polymers, all of which are capable of an effective improvement on the hydrocarbon structure, decreasing viscosity and also flooding oil physically under an increased pressure. Early field trials were initiated to utilize microorganisms to recover residual oil or gas. The microorganisms and their reaction products critically have an effect on oil and gas production in many reservoirs in China. Concerning research on metabolites, several field applications in some oil fields indicate that it is very significant to accurately analyse and evaluate metabolites and further select the most suitable microbe. Moreover, the MEOR program is applied in extra-heavy crude oilfields with relatively good results.

绿色荧光蛋白标记在MEOR中的应用研究

为了充分认识目的优势菌种经油藏运移后在产出水中分布的规律与数量,准确分析和客观评价MEOR现场试验效果,利用绿色荧光蛋白(GFP)基因标记目的菌,通过绿色荧光蛋白跟踪监测目的菌的动态信息。构建含有GFP基因的质粒pET-30a(+)-EGFP,并将其成功导入JD中。对构建的JD(gfp)工程菌进行培养发现,该工程菌在含有Kan质量浓度50μg/mL的培养条件下,重组质粒在JD(gfp)工程菌体内传代稳定,绿色荧光的表达稳定。但是在没有选择压力的培养条件下,重组质粒在JD工程菌胞体内有丢失现象。与野生菌混合培养,JD(gfp)工程菌具有很好的配伍性和竞争性,并且不发生重组质粒的水平转移,因此在环境中释放是安全的。

XJ-21菌株在胍胶压裂液体系中破胶驱油的复合性能

在储层压裂改造过程中,胍胶压裂液体系低温破胶难,储层改造效果差,是新疆油田油藏开发亟待解决的关键技术难题。针对这一技术难题,将微生物强化采油技术应用于压裂液体系中,从新疆油田吉7井区烧房沟组采集到油泥,通过对样品中微生物的富集培养及分离,筛选得到一株能够高产生物表面活性剂的菌株,将其命名为XJ-21。结合菌落形态观察、革兰氏染色及16S rRNA序列分析结果,XJ-21菌株被鉴定为枯草芽孢杆菌(Bacillussubitlis)。FTIR分析确定XJ-21代谢产物中的生物表面活性剂与环脂肽类结构一致。XJ-21菌株与外源ZW-027菌株复配后,复配体系对油藏环境条件具有广泛适应性,不仅在温度为35~55℃的范围内可以产生物酶使胍胶冻胶破胶,还可在50℃下降低样品所在区块的原油黏度,降黏率可达95.45%。在水驱后,使用复配体系驱油与仅用水驱技术相比可以提高10.14%的驱油率。

“双碳”目标下绿色提高采收率技术路径与实践

“碳达峰、碳中和”目标下,油气生产行业在持续增产稳产、确保能源安全的前提下,需要加强负碳、零碳和低碳技术创新,促使产业转型升级。新技术、新工艺、新材料的研发赋予了绿色低碳提高原油采收率技术新的内涵。理论研究与矿场实践表明:CO_(2)驱油、CO_(2)压裂增产、空气(减氧空气或N_(2))驱油、生物质基驱油、微生物基驱油技术碳减排效应明显,为提高原油采收率领域碳中和提供了新路径。未来将继续优化绿色提高原油采收率技术路径,构建新一代绿色低碳提高采收率工程技术体系,开展全流程全生命周期碳减排潜力研究,探索绿色低碳提高采收率技术定量表征方法。

微生物调剖技术的工程应用进展

注水开发目前是我国多数油田主要的开发方式。由于地层的非均质性导致注入水易沿着高渗透带发生窜流,降低吸水剖面,严重影响注水开发效果。常见的化学调剖剂通常有工艺复杂、稳定性差、污染严重和成本高等不足。近年来微生物提高采收率技术在国外迅速发展,逐渐受到国内学者的广泛关注。本文总结微生物调剖技术机理并综述了国内外微生物调剖技术的发展现状,最后提出未来微生物调剖技术应用的挑战与前景。

Application of thermotolerant petroleum microbes at reservoir conditions for enhanced oil recovery

Primary oil recovery is the first stage of hydrocarbon production in which a reservoir uses its natural energy to force hydrocarbon to its wellbore.Secondary oil recovery comes to play when hydrocarbons can no longer be further produced by natural means.The purpose of secondary recovery is to maintain reservoir pressure so as to displace hydrocarbons toward the wellbore.Both primary and secondary recovery processes cannot displace more than 50%of the available hydrocarbons in a reservoir.The remaining hydrocarbons are further recovered through Tertiary/Enhanced Oil Recovery techniques.According to literature,microbial enhanced oil recovery has been identified as a tertiary method used to improve the efficiency of hydrocarbon production from reservoirs.Microbial enhanced oil recovery is a feasible reservoir technology,which has not been widely used in the oil and gas industry owing to the attainment of the requisite reservoir conditions such as temperature within which microbes can thrive.Literature has shown that thermotolerant microbes can withstand optimum temperatures of 50e90℃,while deep and ultra-deep hydrocarbon reservoir temperatures are often above 100℃.This study identifies some isolated thermotolerant microbes from a sandstone reservoir that can withstand temperatures as high as 110℃via conventional methods and molecular analysis.The identified thermotolerant petroleum microbes:Bacillus amyloliquefaciens(A)and Bacillus nealsonii(B)were used to enhance oil recovery from a reservoir.The results showed that the microbial species A and B at a confined pressure of 3.0 MPa and temperature of 27℃,gave 46.4%and 48.6%oil recoveries,respectively,which is comparably higher than the value(26.9%)obtained for the water flooded samples.At temperatures of 80,90,100,110 and 120℃,the oil recovery results show that the recovery factor(55.2%e64.1%)of species B were higher compared to the range(46.7e57.5%)recorded for species A.At the onset of the core flooding experiments,there was an initial increment in oil recovery factor as the temperature increased from 80 to 110℃,whereas,it remained constant within 110e120℃.This trend coincides with the drop in the thermal resistance exhibited by the microbes when exposed to such conditions.The cumulative oil production from the commercial Eclipse simulation closely matched those of the experiment results,whereas,the slight difference can be attributed to the adjustment of the simulation input parameters.The experimental results show that species B can be used to enhance oil recovery at reservoir temperature conditions above 100℃.

The Selection and Breeding of a Novel Microorganism Strain I and Investigation of Core Model Experiment for MEOR

This paper introduces the results of selecting and breeding a micro-organism, Strain I, and its core model experiment investigation for microbial enhanced oil recovery (MEOR). Strain I was separated from the formation water of the Dagang oil field, with analytical results showing that Strain I is a gram-positive bacillus. A further study revealed that this strain has an excellent tolerance of environmental stresses: It can survive in conditions of 70℃, 30 wt% salinity and pH3.5-9.4. Strain I can metabolize biosurfactants that could increase the oil recovery ratio, use crude oil as the single carbon source, and decompose long-chain paraffin with a large molecular weight into short-chain paraffin with a small molecular weight. The core model experiment shows that Strain I enhances oil recovery well. Using 2 vol% of the fermentation solution of Strain I to displace the crude oil in the synthetic plastic bonding core could increase the recovery ratio by 21.6%.

Laboratory studies of rice bran as a carbon source to stimulate indigenous microorganisms in oil reservoirs

There is a great interest in developing cost-efficient nutrients to stimulate microorganisms in indigenous microbial enhanced oil recovery（IMEOR） processes.In the present study,the potential of rice bran as a carbon source for promoting IMEOR was investigated on a laboratory scale.The co-applications of rice bran,K2HPO4 and urea under optimized bio-stimulation conditions significantly increased the production of gases,acids and emulsifiers.The structure and diversity of microbial community greatly changed during the IMEOR process,in which Clostridium sp.,Acidobacteria sp.,Bacillus sp.,and Pseudomonas sp.were dominant.Pressurization,acidification and emulsification due to microbial activities and interactions markedly improved the IMEOR processes.This study indicated that rice bran is a potential carbon source for IMEOR.

微生物+化学复合驱提高高凝油油藏采收率室内实验

针对高凝油油藏析蜡冷伤害、水驱采收率低的问题,运用微生物高通量测序分析、化学驱实验评价方法,利用岩心物理模拟与CT扫描等手段,提出了微生物+化学复合驱组合提高高凝油采收率技术,研制了微生物化学复合驱配方,该体系兼有化学驱大幅度提高驱油效率及微生物降低原油蜡质组分双重优点,最后通过物模实验优化了微生物与化学驱配方段塞组合。实验结果表明:微生物+化学复合驱较水驱提高驱油效率35.19个百分点,较单一化学复合驱可提高驱油效率7.27个百分点,单位质量聚合物增油量提高了1.16 t/t。该研究为高凝油油藏开发后期方式转换、提高采收率提供有效接替技术。

微生物提高采收率过程中促进原油动用的机制

随着石油需求的不断增长,提高采收率越来越重要。近年来,选择微生物及其代谢产物作为驱油材料,可以降低成本、减少环境污染且效果较好。已有不少学者通过渗吸、填砂管模型、驱替、数值模拟等实验方法对微生物提高采收率(microbial enhanced oil recovery,MEOR)的效率进行了研究。总结了微生物驱油的5个机制,并通过比较其对微生物驱油效率的影响,发现渗透率变化、改善岩石表面润湿性和界面张力降低在微生物驱油机制中占主导地位。参与MEOR的细菌能够适应不同条件的储层环境,并代谢出生物活性物质,其中生物表面活性剂应用效果最为明显。将有助于理解微生物与提高采收率的关系,并确定其在增加石油产量中发挥作用的机制,对于MEOR在油气行业的发展具有重要意义。

复杂油气储层微生物提高采收率研究进展

综述了微生物繁殖和驱油有关机理,总结不同微生物提高采收率工艺特点,并以此为基础,介绍了低渗透、高稠油、高温高压、高含水、高矿化度等复杂油气储层环境下微生物提高采收率的研究进展,并展望了不同油气储层下微生物驱油未来发展方向,为相关的研究工作者提供相应的理论基础和研究参考。

微生物与化学驱/气驱协同提高采收率技术研究进展

从物质协同、机理协同及时空协同三个角度阐述了微生物/化学驱/气驱协同提高采收率技术的概念和内涵,综述了微生物/化学驱协同驱油技术(微生物活化水驱、微生物/化学法调驱、微生物/化学驱复合驱油)及微生物/气驱协同驱油技术(空气辅助微生物驱油、微生物/CO_(2)协同驱油)机理、特征及发展现状,未来将继续在微观协同机理、绿色低碳工艺、拓展油藏适用范围方面深入探索。

A STREAMLINE-BASED PREDICTIVE MODEL FOR ENHANCED-OIL-RECOVERY POTENTIALITY

A pseudo-three-dimensional model of potentiality prediction is proposed for enhanced oil recovery, based on the streamline method described in this article. The potential distribution of the flow through a porous medium under a complicated boundary condition is solved with the boundary element method. Furthermore, the method for tracing streamlines between injection wells and producing wells is presented. Based on the results, a numerical solution can be obtained by solving the seepage problem of the stream-tube with consideration of different methods of Enhanced Oil Recovery（EOR）. The advantage of the method given in this article is that it can obtain dynamic calculation with different well patterns of any shape by easily considering different physicochemical phenomena having less calculation time and good stability. Based on the uniform theory basis-streamline method, different models, including CO2 miscible flooding, polymer flooding, alkaline/surfactant/polymer flooding and microbial flooding, are established in this article.

表面活性剂对采油菌生长的影响

为了研究表面活性剂驱油后储层微生物的适应性,本研究选择油田上广泛使用的表面活性剂:脂肪醇聚氧乙烯醚硫酸钠(AES)、十二烷基硫酸钠(SDS)和聚乙二醇辛基苯基醚(Triton X-100),确定采油菌在不同浓度的表面活性剂胁迫条件下的Gompertz模型,并通过拟合参数来衡量拟合度。结果表明,当AES和SDS的浓度高于4×10^(3)mg/L时,生长迟缓期明显延长,最大生长量降低。阴沟肠杆菌对Triton X-100表现出较高的耐受性,AES和SDS浓度低于4×10^(3)mg/L时,拟合效果良好。本研究阐明了微生物提高采收率(MEOR)中表面活性剂对采油菌生长和代谢的作用机制,为微生物驱油的研究提供了理论依据。