Microbial Enhanced Oil Recovery (MEOR)

Abstract

Microbial enhanced oil recovery (MEOR) represents the use of microorganisms to extract the remaining oil from reservoirs. This technique has the potential to be cost-efficient in the extraction of oil remained trapped in capillary pores of the formation rock or in areas not swept by the classical or modern enhanced oil recovery (EOR) methods, such as combustion, steams, miscible displacement, caustic surfactant-polymers flooding, etc. Thus, MEOR was developed as an alternative method for the secondary and tertiary extraction of oil from reservoirs, since after the petroleum crises in 1973, the EOR methods became less profitable. Starting even from the pioneering stage of MEOR (1950s) studies were run on three broad areas, namely, injection, dispersion, and propagation of microorganisms in petroleum reservoirs; selective degradation of oil components to improve flow characteristics; and metabolites production by microorganisms and their effects.     

特重原油油藏微生物采油试验

辽河油田冷43块油藏所产原油含胶质沥青质37％－42％，含蜡5％，粘度9．6－43Pa.s(50℃），密度．960－0．975g/cm^3,已出了国外某些标准规定的微生物采油适应范围，用优选的适应温度范围为40－60℃的两种菌假单胞菌（Pseudomonas sp.)LH－18和短杆菌（Brevibacterium sp.)LH－21的等量混合物，培养基，分别与该区块5口油井所产原油在48℃摇床发酵48小时，使原油粘度降低26％－65％，发酵液表面张力下降10％－19％，pH值由中性变为弱酸性，表明在原油发酵过程中有表现活性物质和酸生成，在该区块蒸汽吞效果很差的同层位5口井的近井地带注入营养液和混合菌液，共7井次，单井一次注入菌液0．5－1．2t，注入后采用机械抽油，5口井中有3口井既增产油又减产水，1口井（间开井）连续生产，这4口特重油井单井微生物吞吐试验获得成功，另1口井产液量和产水量大幅度上升，增产油量极微，同一层位的5口井微生物采油效果相差很大，特别是微生物疏通出水层或通道，其原因有待研究。     

微生物采油技术与油田化学剂

微生物采油技术研究和现场应用范围不断扩大，前景良好。本专论叙述了微生物采油与油田化学剂之间的关系，共分6个部分；①影响微生物采油的油田化学剂简介；②化学剂对微生物的不良作用，包括对微生物呼吸作用，蛋白质、核酸、结构大分子合成及细胞壁功能的直接影响和通过改变环境介质渗透压、氧化还原位，pH值对微生物生长的间接影响；③化学剂影响的评价，包括测定最低影响浓度、作用持续时间，并考虑化学剂在地层内的变化；④化学剂不利影响的消除，包括筛选具有抗某种化学剂的菌种，培育具有特定性能的菌种，如可用于聚合物驱后油田的可降解聚合物的菌种。⑤微生物采油需要的化学剂：碳源、氮源、磷源等，利用内源微生物的驱油技术。⑥简短结论。     

PBS菌的趋化性与提高原油采收率机理

实验验证了PBS菌的趋化性,在物理模型上考察了PBS菌的驱油机理和效果.PBS菌为假单胞杆菌属,兼性厌氧,可利用原油为碳源生长,代谢产物主要为化学结构已确认的一种鼠李糖脂,以及少量脂肪酸、有机醇、气体等.菌液中PBS菌数105～106个/mL,培养温度51℃,实验原油51℃下粘度35.2 mPa·s,驱替水矿化度3.7 g/L.在显微镜载玻片上培养0.5天后,距油水界面10 μm以内的水相(菌液+营养液)中菌数达108个/mL,2天后更达109个/mL,而在10 μm以外的水相中仅为103个/mL.在玻璃盒内培养0.5天后,靠近油水界面处水相中菌数为109个/mL,pH值4.4,鼠李糖脂浓度2.87 g/dL,距油水界面10、20、30 mm处水相中,菌数分别为107、106、105～104个/mL,形成细菌浓度分布梯度.以上实验结果用细菌的趋化性解释.在仿真网络模型上,水驱油后注入1 PV菌液+营养液,51℃培养10天后再水驱,观察并记录了以下驱油机理①乳化-携带,启动剩余油;②剥离油膜或油团;③堵塞大孔道,液流转向.在渗透率1 μm2的板状填砂模型上水驱油采收率为48%,注入1 PV菌液+营养液,在51℃培养10天后再水驱,提高采收率13.6%.图12参6.     

本源微生物驱提高采收率技术在大港油田的应用

分析了本源微生物驱油技术提高原油采收率的机理、特点、油藏适用条件。从区块选择、方案设计、现场实施、效果评价等方面详细介绍了大港油田孔店二断块及港西三区一断块本源微生物驱先导性矿场试验的情况。孔店二断块共进行了15次施工，22口受益油井中有9口井见效明显，含水平均下降2％～5％，累计增油11192t。港西油田三区一断块共实施2口井，受益油井5口，有效率100％。矿场试验表明，采用本源微生物驱油技术，能激活油层中处于休眠状态的好氧和厌氧微生物，这些微生物的代谢产物增加了原油的流动性，使油井原油产量增加，含水下降，从而达到了提高采收率的目的。     

稠油微生物开采技术现状及进展

综述了用微生物方法开采稠油的技术现状与进展，论题如下。①概述。②基本方法：异源微生物采油，包括微生物吞吐和微生物驱；本源微生物采油压大港孔店油田的实例。③主要机理，包括产表面活性剂，降解稠油中重质组分及其他。④技术研究，包括机理性、可行性及经济效益研究，列举了国内外6个实例。⑤现场应用，包括国外1个、国内6个实例。⑥该技术的优势及问题。参22。     

The Application of Microbial Enhanced Oil Recovery Technology in Shengli Oilfield

For the last 20 years Shengli oilfield has done research into the application of microbial enhanced oil recovery (MEOR). The authors summarize and analyze MEOR progress in mechanism research and field application in Shengli oilfield. The results indicate MEOR could improve oil recovery after water flooding and polymer flooding with multiple mechanisms. Cumulative oil increment of MEOR application on seven blocks was 212,366 t. The research and application of MEOR should concentrate on air assisted microbial flooding and indigenous microbial flooding in the future.     

以糠醛抽出油为原料制备三次采油用表面活性剂

以糠醛抽出油为原料,通过磺化制备了一种表面活性剂KOCS。界面张力测试结果表明,在强碱NaOH存在的条件下,当KOVS含量为0．2％,碱含量在0．6％～1．4％范围时,KOCS体系与大庆四厂原油可形成超低界面张力(-10^-3mN／m)。在无碱条件下,KOCS表面活性剂单独用于大港油田枣园1256断块原油时,油-水界面张力可达到10^-2mN／m。KOCS能够满足不同油田化学驱对表面活性剂的要求。     

MEOR的多学科挑战

介绍了筛选MEOR合适细菌的方法,评价其使原油流动的能力和确定原油流动的可靠机理.另外,研究了不同油藏参数对微生物生长的影响.在油藏条件下进行了驱替试验,以验证菌株使地下残余油流动的能力和检测菌株使原油流动的机理.给出了微生物采油的重要机理以及在油田应用MEOR的最重要筛选标准.项目也获得了成果,发现这些成果在很大程度上包括了其他学科的贡献,如微生物学、化学,当然还有石油工程学.形成的跨学科应用有助于进一步提高研究成果.     

激活内源微生物提高原油采收率技术

微生物采油技术可按微生物来源分为外源微生物采油和内源微生物采油两大类，本文综述了通过注入营养剂和混气水激活油层内本源微生物的采油技术，该项技术的工艺较简单，在俄罗斯已进入较大规模的矿场应用试验。综述的论题包括；绪言；基本原理，矿场试验及相关研究；矿场试验设计；矿场试验跟踪监测；对中国微生物采油技术发展的意义。     

石油磺酸盐表面活性剂在三次采油中的应用

根据国内外文献中石油磺酸盐合成和应用实例,对石油磺酸盐表面活性剂的制备、驱油机理、复配体系、国内外矿场试验的情况和存在的问题进行了概述,并对今后的发展方向及应用前景进行了展望。     

Pre-prepared Microemulsion Flooding in Enhanced Oil Recovery: A Review

It is evident that one of the important applications of microemulsions is in enhanced oil recovery (EOR) process due to its unique properties such as ultra-low interfacial tension. The injection of microemulsion slug reduces the interfacial tension between the crude oil and reservoir brine, which leads to mobilization of substantial fraction of residual oil. In general microemulsion flooding is classified into two distinct categories, pre-prepared and in situ prepared, depending on its preparation method. The authors present a detailed discussion of microemulsion preparation and summarizes major articles on pre-prepared microemulsion flooding in EOR processes. Their review opens new horizons for the future researches on pre-prepared microemulsion flooding in EOR processes by organizing the literature data and comparing them.     

The Synthesis and Performance of Sodium Methyl Ester Sulfonate for Enhanced Oil Recovery

Abstract

Due to the high cost of surfactant production caused by petrochemical feedstocks, much attention has been given to nonedible vegetable oils as an alternative source of feedstock. A new nonedible oil-derived surfactant based on the Jatropha plant is synthesized. A single-step route was used for synthesizing sodium methyl ester sulfonate (SMES) for enhanced oil recovery application. The performance of the resultant surfactant was studied by measuring the interfacial tension between the surfactant solution and crude oil and its thermal stability at reservoir temperature. The SMES showed a good surface activity, reducing the interfacial tension between the surfactant solution and crude oil from 18.4 to 3.92 mN/m. The thermal analysis of SMES indicates that 26.1% weight loss was observed from 70°C to 500°C. The advantage of the new SMES is the low cost of production, which makes it a promising surfactant for enhanced oil recovery application and other uses.     

微生物采油技术

该文综述了微生物采油技术的优点、微生物提高原油采收率的机理、微生物采油工程的油藏筛选标准和筛选程序、菌种的选择、营养液的配制以及微生物采油技术的现场应用。并对微生物采油技术在胜利油田的应用前景提出了看法和建议。     

Studies on the Production of Biosurfactant for the Microbial Enhanced Oil Recovery by Using Bacteria Isolated from Oil Contaminated Wet Soil

Abstract

There are obvious advantages of biosurfactants over chemical surfactants. The developing shortage of oil and rapid increase of oil prices is putting pressure on oil companies to recover as much oil as possible from the wells to sustain the oil economy. Therefore, there is a need to research some “super bugs,” which can produce active and stable biosurfactants in good yields. Five bacterial strains presently isolated from the oil-contaminated soil were selected for the screening for biosurfactant production, via three different methods: surface tension measurements, drop-collapsing test, and emulsification index (EI₂₄) test. Two thermophillic isolates coded as SGI and LFA were found to be the suitable candidates for biosurfactant production. In fact, the biosurfactant produced by the isolate SGI led to the reduction of surface tension up to 26 m/N/m; thus, SGI was selected for the further studies. Biosurfactant production by the thermophillic isolate SGI was found to be growth-associated in all conditions tested. Biosurfactant production using different cheaper carbon substrates was studied. The production of biosurfactant was also studied using isolate SGI, under different conditions of high temperature, NaCl concentration, pH, carbon source, and initial nitrogen concentration. The biosurfactant was found to produce a relatively stable emulsion with hydrocarbons at a wide range of pH. It was also found to be stable at various pH ranges (7.0–14.0) for SGI and was also found to be thermostable for 1 hr at 125°C, based on the value of surface tension. There is a wide array of further studies in the area of microbial enhanced oil recovery (MEOR) including further boosting the activity of the isolate by using adaptation, enrichment, and nutrient enrichment techniques.     

Evaluation of Surfactants for the Cost Effective Enhanced Oil Recovery of Assam Crude Oil Fields

Based on a hierarchial methodology, the article presents the comparative efficacy of Vim commercial detergent for the purpose of surfactant enhanced oil recovery of Assam crude oil in Indian reservoirs. Suitable technical and economic indices were defined to explore the economic competence with other surfactants such as sodium dodecyl benzene sulfonate and sodium dodecyl sulfonate. It was evaluated that the detergent formulation provided the following performance characteristics: I_C = 13.43 mN/m.g/L surfactant solution, surfactant sustainability index = 3.88 × 10^?3 mN/m.$/L surfactant solution, cost ratio = 0.32 ? 0.52 $ surfactant/$ crude oil recovered and 14.7–15.1% tertiary recovery with respect to original oil in place. Further ultralow interfacial tension formulations were also achievable with the commercial detergent.     

Numerical Simulation of Enhanced Oil Recovery by Alkali-surfactant-polymer Floodings

In the present study numerical simulation of sand pack flooding with alkali–surfactant–polymer for enhanced oil recovery has been studied using an advanced compositional simulator named STARS available from the Computer Modeling Group. The flooding experiment shows that the chemical formulations are able to recover additional oil more than28% with proper formulation. Therefore, the main motivation of the work is simulation and comparison of results. Different chemical slugs such as alkali, surfactant, and polymer were taken and their effects on water cut, oil cut, cumulative recovery and additional recovery were simulated by the software using experimental data. The results obtained using the simulator has been compared with the available sand packed flooding laboratory experimental data.     

The Characterization of Natural Surfactant and Polymer and Their Use in Enhanced Recovery of Oil

Abstract

Studies have been done to examine the applicability of natural surfactant and polymer for enhanced oil recovery. A detailed investigation has been made on interfacial and rheological properties of natural guar gum polymer and surfactant obtained from extracted soapnut shell. Based on the physicochemical properties of the surfactant and polymer solutions, optimum compositions were designed for flooding experiments. Three sets of experiments were performed to study enhanced oil recovery by injecting the same pore volume of polymer, surfactant–polymer, and alkaline–surfactant–polymer slug after brine flooding. Significantly higher additional recovery (~24% original oil in place) was obtained by alkaline–surfactant–polymer flooding compared to the other two methods over waterflooding (~50% original oil in place).     

Microemulsions in Enhanced Oil Recovery: A Review

Abstract

Microemulsions have recently made advances in enhanced oil recovery processes in which chemicals, especially surfactants, are used to recover the oil from natural oil reservoirs. This technique relies on the knowledge of interfacial properties among oil, water, and solid rock reservoirs in the occasional presence of natural gas under extreme conditions. Surfactant-based chemical systems have been reported in many academic studies and their technological implementation is a potential candidate in enhanced oil recovery (EOR) activities. For instance, it was determined that a mobilized buffer (polymer) with viscosity either equal to or greater than the mobilized oil enhanced the recovery efficiency considerably. However, EOR based on chemicals like alkaline–surfactant–polymer (ASP) is a complex technology requiring a high level of expertise for its industrial implementation. The surfactant–polymer interaction is a rapidly growing research area for efficient oil recovery by improving slug integrity, adsorption, and mobility control. This review article evaluates the injecting fluid system to highlight some recent advances in the use of chemicals in EOR, especially with microemulsions. It further reveals the current status and future outlook for EOR technology in oil fields and describes the opportunities for strategic utilities and load growth in petroleum industry.     

三次采油技术的发展

国内主要油田三次采油技术有很大的发展,三次采油这个系统工程在组织管理和技术攻关上具有许多成功做法。三次采油作为注水开发后期的主要接替技术已经形成共识,大庆油田已在北二区、北一中块、喇北东块等６个区块开展面积达５０ｋｍ~２的注聚采油,１９９７年三次采油年产油量已达５００×１０~４ｔ,占总采油量的８．８％;胜利油田１９９７年已投注８个化学驱试验项目,化学驱面积达３０．７ｋｍ~２,１９９７年三次采油量为１００× １０~４ｔ以上;大港油田注聚面积近１２ｋｍ~２。