宝力格油田微生物驱物理模拟实验研究

针对宝力格油田微生物驱过程中存在的问题,通过室内物理模拟实验对不同驱替介质提高采收率的作用、产出细菌浓度与注入细菌浓度的关系以及营养液浓度对维持产出液细菌浓度的影响进行了深入研究。结果表明,通过注入1%的菌液及营养液进行微生物驱时可提高采收率16.77%,当产出液经补充营养液及菌液并发酵10~12 h后再继续进行微生物连续驱时可进一步提高采收率5.74%,产出液细菌浓度达到108个/mL以上。但由于岩心对菌体的吸附作用以及岩心渗透率对微生物运移的影响,产出液细菌浓度始终要低于注入细菌浓度一个数量级以上。采用产出液回注并补充0.25%以上的营养液时,可使产出液细菌浓度维持在107个/mL以上。研究结果可为现场注入方案设计提供技术支持。     

特低渗油藏微生物驱影响因素数值模拟研究

采用数值模拟方法对影响朝阳沟油田微生物驱油效果的各项因素进行分析发现：微生物浓度对微生物驱油效果具有一定的影响；一定的微生物浓度下，存在合理的微生物用量；而相同微生物用量条件下，多段塞式注入优于单一段塞式注入；在注微生物1a以后，再注入一段营养液，可以提高微生物的驱油效果。数值模拟表明，微生物驱6a后较水驱提高采收率1．73％，并使含水率降低，最大降幅可达14．32％。     

驱油微生物营养组分在油藏中的消耗吸附及运移规律研究

基于对宝力格油田整体微生物循环驱过程中产出液的长期跟踪监测发现,从油井产出液中监测到的营养液浓度要远低于对应水井的注入浓度,尤其是葡萄糖的浓度始终检测不到,而且在油井产出液中监测到的微生物数量要比注入井低2个数量级左右。为了弄清楚注入的营养液组分在地层中的运移消耗情况,文章通过室内大型物模驱油实验及现场跟踪监测来深入研究微生物、营养液不同组分及代谢产物在油藏中的消耗、吸附及运移规律,结果发现,注入的葡萄糖在地层中有较强的吸附作用,而且由于代谢很快导致其难以进入到油藏深处,这也是目前制约现场微生物驱油效果的一个重要因素。代谢产物的分析表明葡萄糖主要被微生物代谢为有机酸,而葡萄糖及有机酸浓度对微生物的生长繁殖有着重要影响。氯化铵和磷酸二氢钾在地层中的吸附相对较小,但磷酸根在地层中的运移速度要比铵根慢,而且在pH较高的情况下很容易与地层水中的钙镁离子结合形成沉淀。该研究结果为微驱营养液的优化及注入工艺设计提供了重要的理论依据。     

芳6断块微生物驱油数值模拟

根据微生物在多孔介质中运移的规律，微生物在驱油过程中的生长与衰竭、深积、趋化性、扩散、对流弥散和培养基消耗以及微生物对原油的降解、乳化等特性，建立了适合微生物驱油的数学模型。利用该模型系统地研究了驱替过程中微生物浓度、注入段塞尺寸和注入方式对微生物驱油效果的影响。     

内源微生物采油技术在大庆油田南二区东部聚驱后油层中的应用

针对聚驱后油藏含水上升速度快、产量递减幅度大、剩余油开采难度逐渐增加的问题,在大庆油田南二区东部聚驱后的水驱区块开展了小区块内源微生物驱油现场试验,对试验过程中的注入方式、注入工艺及油藏动态变化情况进行分析,结果表明,加入保护段塞的注入方式能充分发挥营养液激活功效,有利于微生物驱油效果的发挥;内源微生物驱增加了原油的轻质组份,从而提高了原油流动性;油层剖面动用状况得到改善,提高了差油层采油量。试验的4口采油井最高增油13.4 t/d,综合含水最低下降2.2个百分点,表明聚驱后油藏仍然可以采用内源微生物驱油技术进一步提高原油采收率。     

微生物驱油数值模拟初探

为探讨微生物采油(MEOR)过程涉及的各种机理,初步建立一维三相的微生物驱油数学模型,用以描述细菌和营养液在油藏中的传输以及细菌的繁殖,为MEOR领域工程设计及评估提供依据。该模型考虑流体中携带的细菌量和细菌沉积速率,用Gruesbeck和Collins给出的考虑细菌沉积的方程描述细菌繁殖及传输情况,体积流速与所通过的多孔介质的绝对渗透率有关;选择Langmuir方程描述营养物质的吸附现象,并考虑营养液在饱和多孔介质的水中的分散和渗滤;用Monod方程表示细菌生长率与营养液浓度的关系。将该数学模型的偏微分方程组转化成有限差分方程组,然后通过将非线性系数项线性化得到线性代数方程组,从而求得所需求的未知量的分布及变化。取一口现场生产井的生产资料进行数值模拟,结果表明,所建立的数学模型可以基本上反映微生物驱油的基本机理。根据模拟计算出的结果认为,当微生物注入地层后:①油井产量前期变化不大,后期明显增加;②含油饱和度在前30d变化率最大(但产量并未增加),此后变化率越来越小;③含水饱和度随时间的增加而增加。图2参12(王孝陵摘)     

稠油油藏聚合物驱剖面反转现象室内实验

为探讨稠油油藏聚合物驱剖面反转规律,建立了与现场实际相似的非均质物理驱替模型,并用聚合物驱替模拟岩心,研究油层渗透率级差、注入浓度、注入时机对聚合物驱剖面反转的影响。实验结果表明:渗透率级差越大,剖面反转出现越早,反转程度越大,说明对于级差较大的稠油油藏用聚合物驱油效果较差;聚合物驱油过程中聚合物浓度越大,剖面反转越早,原油采收率升高,但增长速度变缓,说明在聚合物驱油时需要对聚合物的浓度范围进行界定;聚合物驱油注入时机越早,剖面反转出现越早,应结合生产实际情况选择适当注入时机。该研究成果对聚合物驱提高稠油油藏原油采收率具有指导意义。     

稠油油藏聚合物驱剖面返转现象室内实验

为探讨稠油油藏聚合物驱剖面返转规律,建立了与现场实际相似的非均质物理驱替模型,并用聚合物驱替模拟岩心,来研究油层渗透率级差、注入浓度、注入时机对聚合物驱剖面返转的影响。实验结果表明：渗透率级差越大,剖面返转出现越早,返转程度越大,说明对于级差较大的稠油油藏用聚合物驱油效果较差;聚合物驱油过程中聚合物浓度越大,剖面返转越早,原油采收率升高,但增长速度变缓,说明在聚合物驱油时需要对聚合物的浓度范围进行界定;聚合物驱油注入时机越早,剖面返转出现越早,应结合生产实际情况选择适当注入时机。该研究成果对聚合物驱提高稠油油藏原油采收率具有指导意义。     

S12区块内源微生物驱油技术现场试验

为了利用微生物技术进一步提高原油采收率,针对S12区块开发现状和地质条件,通过对油藏内部的微生物群落结构组成、地层流体的性质进行分析,确定了实施内源微生物驱油技术的可行性。通过大量室内试验筛选了可以激活油藏中利于采油细菌的营养配方,并通过物理模拟试验确定了激活剂的注入浓度,物理模拟试验结果表明,在进行水驱之后,实施内源微生物驱油技术可提高采收率9个百分点以上,在室内试验的基础上进行了现场注入试验。现场跟踪测试结果表明,注入筛选的营养剂配方以后,油藏中的细菌被激活,并代谢产生了有利于提高原油采收率的物质,起到了一定的增油效果。     

微生物与空气协同驱油的耗氧规律

微生物与空气协同驱油是一种新的驱油方法,其主要机理为利用空气中的氧气提高微生物生长代谢速率,同时微生物耗氧使空气驱变得更为安全。通过实验研究不同初始溶氧浓度下实验菌种的生长规律和耗氧规律,及溶氧浓度对微生物脱油效率的影响。结果表明:在增氧与未增氧的条件下,实验菌种生长均存在停滞期、对数生长期、稳定期和衰退期,初始溶氧浓度为4.5和5.5 mg/L时,微生物生长的最大浓度是未增氧时的3倍以上;对数生长期溶氧浓度呈对数降低趋势,稳定期和衰退期溶氧浓度呈线性降低趋势,油藏内耗氧主要为补偿微生物衰退时数量减少的生长耗氧;微生物脱油效率随初始溶氧浓度的增大而增大。在微生物耗氧规律和油藏渗流规律的基础上,建立了仅考虑微生物耗氧时油藏内氧浓度计算数学模型,计算了不同注入参数下氧浓度分布。结果显示,耗氧后,油藏内氧浓度随油藏半径的增加指数下降,油藏内有足够的氧供微生物生长;微生物耗氧可将空气中的氧浓度降到安全浓度,微生物耗氧到氧安全浓度的最小油藏半径约为145 m。     

空气辅助微生物驱油技术

为改善兼性厌氧微生物在高温、高压、厌氧油藏条件下的驱油性能,对微生物驱现场试验区油藏流体中筛选的兼性厌氧菌株开展优化研究,分别从模拟发酵系统和物理模拟试验2方面研究溶氧条件优化对厌氧环境条件下兼性厌氧菌株代谢及驱油性能的改善。研究表明,在适度溶氧条件下,发酵液菌体密度、代谢产物浓度明显增高,溶氧参数在4.0mg/L时,培养液相对最快达到对数生长期,进一步试验确定出兼性厌氧微生物BS36培养最佳溶氧量为4.2mg/L。物理模拟试验表明,空气辅助条件下微生物驱最终采收率比单一微生物驱提高5.5个百分点。现场实施工艺配套研究基础上,进入现场试验获得成功,进一步提高微生物驱现场试验效果。     

Comparison of in-situ and ex-situ microbial enhanced oil recovery by strain Pseudomonas aeruginosa WJ-1 in laboratory sand-pack columns

Microbial enhanced oil recovery (MEOR) applies biotechnology to improve residual crude oil production from substratum reservoir. MEOR includes in-situ MEOR and ex-situ MEOR. The former utilizes microbial growth and metabolism in the reservoir, and the latter directly injects desired active products produced by microbes on the surface. Taking biosurfactant-producing strain Pseudomonas aeruginosa WJ-1 for research objects, in-situ enhanced oil recovery and ex-situ enhanced oil recovery by biosurfactant-producing strain WJ-1 were comparatively investigated in sand-pack columns.The results showed that P.aeruginosa WJ-1 really proliferated in sand-pack columns, produced 2.66 g/L of biosurfactant, altered wettability, reduced oil-water interfacial tension (IFT) and emulsified crude oil under simulated in-situ process. Results also showed that higher biosurfactant concentration, lower IFT, smaller average diameters of emulsified crude oil were obtained in in-situ enhanced oil recovery experiment than those in ex-situ enhance oil recovery experiment. Similar wettability alteration was observed in both in-situ and ex-situ enhanced oil recovery experiment. The flooding experiments in sand-pack columns revealed that the recovery of in-situ was 7.46%/7.32% OOIP (original oil in place), and the recovery of the ex-situ was 4.64%/4.49% OOIP. Therefore, in-situ approach showed greater potential in enhancing oil recovery in contrast with ex-situ approach. It is recommended that the stimulation of indigenous microorganisms rather than injection of microbial produced active products should be applied when MEOR technologies were employed.     

施工因素对微生物驱油效果影响的物理模拟研究

为了提高微生物驱油效果,开展了施工因素对微生物强化采油效果影响的物理模拟试验。利用"四因素三水平"正交试验设计方法,将注入方式、注入量、关井时间及重新开井时的微生物驱替速度分3个水平进行微生物驱替试验。驱替试验按在水驱之后注入微生物关井一段时间、再利用微生物发酵液驱替的顺序进行。评价各因素在不同水平组合下的采收率,从而优选出各因素最佳水平。利用正交试验设计方法设计的驱替试验结果优化,采用无机培养基和接种活化的菌液按照1:1的段塞注入方式,注入量为0.6倍孔隙体积,关井2 d,重新开井时的驱替速度为3倍孔隙体积/h时微生物强化采油效果最佳,这一最优组合方式在水驱产水率达到95%的基础上,采收率可以进一步提高近32百分点。这表明微生物注入方式等施工参数对微生物强化采油效果有较大影响,在实际施工中应先进行参数优化,以取得最佳强化采油效果。      

微生物采油矿场应用研究进展

对国内外微生物采油（MEOR）矿场试验研究进展情况作了综述。分初期到中期（上世纪70世代以前）和中期到现在（70年代以后）,简述了全世界进行的MEOR矿场试验,列表介绍了1979年以后发表的21例MEOR的注入微生物,实验方式（单井吞吐或驱替）及结果,讨论并列表给出了MEOR的矿物应用条件,并与其他EOR方法作了比较,论述并讨论了MEOR矿场试验的一般程序,包括油田调查,注入微生物选择,对油 层的适应性,与油层本源微生物的竞争特性,提高采收率及添加的营养源,对MEOR矿场应用前景作了展望。     

Using biosurfactant producing bacteria isolated from an Iranian oil field for application in microbial enhanced oil recovery

Microbial enhanced oil recovery (MEOR) is a useful technique to improve oil recovery from depleted oil reservoirs beyond primary and secondary recovery operations using bacteria and their metabolites. In the present study, the biosurfactant production potential of Bacillus licheniformis microorganisms that were isolated from oil samples of Zilaei reservoir in the southwest of Iran was explored under extreme conditions. Growth media with different temperatures of 40, 50, 60, and 70°C; salinities of 1, 3, 5, and 7 wt%; and yeast extract concentrations of 0.5, 1, 1.5, and 2 g/L were used to find the optimum growth conditions. The results demonstrated that bacteria grown in a mineral salt solution with temperature of 50°C, salinity of 1 wt% and yeast extract concentration of 1 g/L has the highest growth rate and therefore, these conditions are the optimum conditions for growing the introduced bacterium. This isolate was selected as the higher biosurfactant producer. The obtained biosurfactants by bacteria isolated in a medium with these conditions could reduce the interfacial tension of crude oil/water system from 36.8 to 0.93 mN/m and surface tension of water from 72 to 23.8 mN/m. The results of the core flooding tests showed that the tertiary oil recovery efficiency due to the injection of microorganisms was 13.7% of original oil in place and bacteria could reduce the oil viscosity by 41.242% at optimum conditions. Based on these results, the isolated microorganism is a promising candidate for the development of microbial oil recovery processes.     

油田水中细菌群落分析

油田水中细菌群落分析，对于外源性和内源性微生物采油技术的研究和开发都是必要的。介绍了油田水中常见的7类细菌对微生物采油的有益和有害作用。采用三管平行MPN或绝迹稀释法和浇注平板法对胜利油田S12块回注污水和5口油井产出水中有益菌(石油烃降解菌HDB，脱氮菌DNB，产甲烷菌MPB)和有害菌(硫酸盐还原菌SRB，铁细菌IB，硫细菌SB，腐生菌TGB)群落进行了计数分析，求得了最大可能含菌量，结果表明胜利S12块油藏内源微生物群落较丰富，3种有益菌和4种有害菌普遍存在，在各水样中各类菌的含量有所不同，含量总体较低。认为S12块油藏可以注入合适的营养物质，选择性地激活微生物采油有益菌，抑制有害菌，提高油藏采收率。表2参21。     

Dynamic investigation of microbial activity in microbial enhanced oil recovery (MEOR)

The activity of reservoir microorganism is essential to Microbial enhanced oil recovery (MEOR). This present paper investigates the relationship between the microbial activity and production performance by means of long-scale & long-term experiments. The six rounds of nutritional injection was carried out in 135 days. During the microbial flooding experiment was performed recovering additional oil (10.44% Original Oil in Place, OOIP) after first water flooding. There is a positive correlation between water content and shannon index. And the fourth round of nutritional injection causes a considerable reduction in water content, while the concentration of Methyl-coenzyme reductase subunit alpha (mcrA) reaches peak value. In microbial flooding and reference water flooding, the concentration of mcrA maintained higher level with the low concentration of acetic acid. There are intimate correlation between water content and mcrA concentration & bacterial diversity (shannon index), which can be consider the symbol to guide the MEOR filed test.     

Modelling of microbial enhanced oil recovery application using anaerobic gas-producing bacteria

Microbial enhanced oil recovery （MEOR） methods apply injection of bacteria to depleted oil reservoirs to produce oil, which had remained unrecovered after the conventional methods of production. The ability ofthermophilic anaerobic bacteria to produce gas as the main mechanism in potential MEOR in high salinities of 70-100 g/L was investigated in this study. Maximum gas production of up to 350 mL per 700 mL of salty solution was produced at a salinity of 90 g/L stably during 2-4 days of experiment. The experimental results were upscaled to the Snorre Oilfield, Norway, and simulated using ECLIPSE software for 27 months. The best scenarios showed that the increase in oil recovery on average was at 21% and 17.8% respectively. This study demonstrated that anaerobic bacteria used in biogas plants could be an attractive candidate for MEOR implementation due to their ability to withstand high temperature and salinity, and produce gas in large volumes.     

吉林油田微生物提高原油采收率现场试验研究

本文介绍了吉林油田现场试验研究的历程.建立了采用DNA鉴定用于微生物提高原油采收率的微生物的新技术.筛选出了用于现场试验的有用的微生物.通过就地注入糖蜜微生物单井吞吐与驱替试验,考察了油藏中被激活细菌的行为,原油收率,含水率及原油的粘度.代谢生物多糖的CJF-002用于现场试验中的微生物中最好的菌种.因为它可以使用糖蜜作为营养源,产生少量的CO2及大量的水不溶性的生物聚合物.它在油藏的代谢行为表明CJF-002具有微生物提高原油采收率良好潜力.