大庆卫星油田微生物驱油体系构建与评价

大庆卫星油田T区块存在大量的低效井及长关井,这类油井大多存在注水不受效、产量递减快以及含水率上升快等问题.针对T区块的油藏条件及微生物群落结构特征,通过细菌培养及物模实验,构建适合该区块的微生物驱油体系,有效提高原油采收率.研究表明:在构建微生物驱油体系时,需满足激活后总菌浓度大于108个/mL、烃氧化菌浓度大于106个/mL、表面张力小于45mN/m,且原油乳化效果良好;T区块内源菌激活效果较差,但外源菌枯草芽孢杆菌SL与油藏内源菌匹配性好,且具备良好的乳化效果;筛选得到枯草芽孢杆菌适用于T区块最佳营养剂配方为(NH4)2HPO42.0 g/L+NaNO3 3.0 g/L+糖蜜1.2g/L+玉米浆干粉3.0 g/L.该微生物驱油体系可降低表面张力至35.23 mN/m,可降低原油黏度88％,可提高采收率最高达12.21％,具备良好的现场应用潜力.     

复合驱油菌株提高安塞低渗透油田采收率实验

从安塞油藏环境中分离到两种高产生物表面活性剂的优良驱油菌株,经鉴定为铜绿假单胞菌DN001和枯草芽孢杆菌DN002. 通过室内和现场试验评价了驱油微生物及其复合菌株降低表面张力和界面张力的能力、对原油的乳化性能以及对当地油藏的环境适应性。结果表明,复合菌株发酵液可将水的表面张力从72 mN/m降低到25.1 mN/m,并且发酵液的油水界面活性较高,平衡界面张力为0.954 3 mN/m.筛选的微生物菌体在安塞油田油藏环境中可大量繁殖。室内驱油模拟实验表明,经复合微生物驱替作用后,采收率可提高17.38%,说明筛选的菌株驱油性能较强,微生物驱油室内评价结果为其在安塞油藏现场应用提供了可靠的试验依据。     

安塞油田微生物驱油提高采收率机理研究

通过室内实验对安塞油田在用的微生物驱油菌种铜绿假单胞菌、枯草芽孢杆菌进行生长活动规律研究、运移能力评价、降解原油机理分析和油层解堵能力研究,分析了微生物驱油提高采收率机理。数据表明绿铜假细胞单菌、枯草芽孢杆菌在安塞油田长6油藏中具有较好的繁殖能力和运移能力,浓度3%微生物溶液可有效地改善原油物性,使原油中轻质烃组分增加,重质烃组分减少,使油藏从亲油转变为亲水,提高洗油效率。并且微生物溶液的代谢产物还可有效地解堵油层无机和有机堵塞,提高油藏渗透性。     

辽河高凝油微生物采油菌剂研究及应用评价

针对高凝油含蜡高、凝固点高、流动性差及开采难度大的问题,选用铜绿假单胞菌配合嗜热脂肪地芽孢杆菌和嗜热脱氮地芽孢杆菌,采用四组分分析法和饱和烃气相色谱法等方法开展了微生物提高高凝油采收率菌剂研究和应用评价。结果表明:菌种对原油四组分存在选择性降解,降解率为23.0%~42.3%,同时菌种可以将高凝油中长碳链饱和烃降解为短碳链烃类,w(nC_(21))/w(nC_(22))值和w(nC_(21)+nC_(22))/w(nC_(28)+nC_(29))值增大0.33~0.57;铜绿假单胞菌发酵液表面张力从72.21 mN/m降低至26.81 mN/m;嗜热脂肪地芽孢杆菌与嗜热脱氮地芽孢杆菌2种芽孢杆菌乳化高凝油的E24值分别为70.6%和82.3%;基于嗜热脂肪地芽孢杆菌、嗜热脱氮地芽孢杆菌和铜绿假单胞菌3种细菌性能设计的兼容本源微生物的复合微生物采油菌剂可使高凝油黏度降低63.86%,凝固点降低6℃。物理模拟驱油实验表明:该微生物复合菌剂可在中渗(200 mD)及低渗(50 mD)条件下使高凝油采收率提高6.46%~8.48%。6口油井的微生物吞吐采油试验证明该微生物复合菌剂性能稳定,可使高凝油采收率大幅提高,具有良好的工业应用前景。     

原生地衣形芽孢杆菌和枯草芽孢杆菌在微生物提高采收率中的作用

微生物产生的脂肽被分离出来,用于微生物提高采收率研究.约60 g的活性细菌从被原油污染的土壤中分离出来,该土壤取自伊朗Tehran地区的Tehran炼油厂中原油储油罐附近.然而,大多数室内实验已经生产出了脂肽,这种脂肽是由一种纯微生物培养方法产生的.溶血测试表明,这些分离液中存在两种可产生表面活性剂的物质.菌株设计为C2和E1.通过生态学、生物化学及分子生物学测定(16 SrRNA),菌株被确定为地衣形芽孢杆菌和枯草芽孢杆菌.乳化活性和表面张力测试表明,这种分离液可产生大量表面活性剂.C2和E1的主要产物为脂肽,它可将界面张力从65 mN/m降到30 mN/m.C2、E1分别使原油乳化92%、90%.这是第一次报道原生地衣形芽孢杆菌和枯草芽孢杆菌具有产生表面活性剂的能力,而这两种菌均源自伊朗炼油厂被油污染的土壤中.     

微生物驱矿场采出液中生物代谢产物

检测微生物采油(MEOR)过程采出液中的有机物组成特征是研究微生物采油机理的重要方法。针对MEOR采出液中有机物组成复杂,生物表面活性剂组成分析困难的特点,采用傅里叶变换离子回旋共振质谱仪(FT-ICR-MS)对新疆六中区微生物驱油过程中3口采油井不同时期采出液中的含氧极性化合物组成进行研究。检测到样品中含氧极性化合物含量最高的为O2、O3、O4、O7、O9类化合物,在微生物驱替过程中,样品中的O7和O9类化合物含量升高,检测到的鼠李糖脂有C_(16)H_(30)O_7、C_(18)H_(34)O_7、C_(14)H_(26)O_7、C_(18)H_(30)O_7、C_(14)H_(26)O_7、C_(24)H_(44)O_9,主要为O7和O9类的单鼠李糖脂。结果表明研究区块微生物驱油过程中激活的内源微生物能够在地层环境中代谢产生鼠李糖脂,随着微生物驱油的进行,鼠李糖脂的种类变多。     

安塞油田驱油微生物多样性研究及筛选

利用微生物及其代谢产物作用于原油提高采收率,首先必须了解油藏本源微生物种类,进行油藏微生物菌种多样性分析。提取安塞油田油水样品,进行菌种分离培养、提取和纯化DNA,设计适合的引物进行目的基因PCR扩增、高通量测序,对序列结果进行生物信息学分析,得到安塞油田驱油微生物多样性研究结果。分析认为安塞油田本源微生物种类丰富,主要是芽孢杆菌纲、梭菌纲、α-变形菌纲及γ-变形菌岗等细菌,又以芽孢杆菌岗属占优势分布。在此基础上筛选出一株产生物表面活性剂微生物,发酵液稀释30倍后与原油的界面张力仅为1.727 6 m N/m,具有较强的降低油水界面张力的能力,筛选出一株产生物聚合物微生物,发酵液中生物聚合物含量高达800 mg/L,具有较强的产生物聚合物能力。最终由这两种微生物菌种构建微生物驱油体系。     

微生物与三元复合驱结合提高原油采收率探索研究

室内筛选的8株兼性厌氧菌以原油为唯一碳源在油层条件下能够很好的生长、繁殖,经合理复配,配伍菌可降解重组分原油,使轻组分增加28．4％,含蜡含胶量降低30％～50％,原油流动性变好,并产生生物表面活性剂、酸液,使原油酸值提高20倍以上,发酵液中有机酸含量提高19．5倍。作用后原油进一步降低了与三元体系间的界面张力。天然岩心驱油实验表明,发酵液稀释2倍,表面活性剂浓度为0．04％,先注微生物关闭模型5d,再进行发酵液配制的复合体系驱替,采收率比水驱提高20．25％(OOIP);若先注微生物,再用现有三元配方(大庆自行研制)驱替,提高采收率幅度平均在29％(OOIP),比单独三元复合体系驱油采收率增加9％左右。由此可见,应用微生物技术与化学驱结合的方法,能够进一步提高原油采收率。     

微生物—三元复合驱提高采收率技术的探讨

碱和合成的表面活性剂二元复合驱（AS）是一项带有方向性的廉价的提高采收率技术。在碱和表面活性剂的水相混合体系中再加入聚合物形成碱-表面活性剂-聚合物三元复合驱（ASP）可以进一步提高石油采收率。原油中的酸性物质与三元体系中的碱中和,在油水界面形成活性物质,降低油水界面张力（IFT）。本文所描述的三元复合驱和微生物技术的结合方法对单独三元复合驱不能起作用的原油应用该项技术是一项经济有效的创新技术。这项技术是基于微生物可以改变原油;产生酸性物质如羧酸,并在油水界面上被碱混合物中和。应用氧化烃类微生物;比如节杆菌（arthrobacter.sp）,在实验室摇瓶论验中发现原油样品中酸含量增加。测量微生物处理过的原油和碱／表面活性剂混合物之间的悬滴界面张力低于没有利用微生物处理原油的值。对于用节杆菌处理过的原油;界面张力从0.327mN／m（未处理）降到0.07333mN／m。为了优化该项技术,筛选了多种微生物。并开展了岩心驱替实验,定量确定原油采收率。应用微生物驱和三元复合驱技术进行的实验室岩心驱油实验表明,微生物驱和三元复合驱结合技术的原油采收率比单独微生物驱和单独三元复合驱的都高。经微生物预处理的采油方法,原油采收率的提高值与微生物处理的原理酸含量的增加     

微生物与弱凝胶复合驱油配伍性

为了推动宝力格油田巴19断块弱凝胶调驱和微生物驱复合驱油实验研究,对弱凝胶与微生物的配伍性进行了实验分析。芽孢杆菌Chang和Jian分离自巴19断块地层水,这两株菌对原油的降解率分别达到160 mg/d和138 mg/d、降黏率达到50.5% 和66.3%,形成的原油乳状液油滴平均粒径为38.22 μm和18.54 μm。经测定,两株菌均能代谢产生脂肽类表面活性剂,产量分别为682 mg/L和476 mg/L。微生物和弱凝胶的配伍性实验发现,菌株Jian对弱凝胶的成胶性能没有影响;在弱凝胶调驱的现场使用浓度内,Jian的生长代谢、乳化分散(表面张力为40.78 mN/m、乳化原油平均粒径为22.46 μm)、降黏(降黏率为132 mg/d)和降解(降解率为63.6%)能力也没有明显降低。弱凝胶和微生物复合驱油在弱凝胶驱的基础上可提高采收率7.26%,在微生物驱基础上可提高采收率12.67%,说明菌株Jian与该弱凝胶复合驱油具有良好的配伍性。     

Synthesis,interface activity and oil flooding experiment with an authentic sandstone microscopic model of cationic gemini surfactant

In this work, a series of cationic gemini surfactants with different hydrophobic tails were prepared and characterized by element analysis, IR spectra, and ¹H NMR spectra. The influencing factors of physic-chemical properties of these surfactants were carefully studied. The critical micelle concentration (CMC) of all the surfactants ranged from 3.87 × 10^?4 mol L^?1 to 8.97 × 10^?4 mol L^?1 and the values (γ_cmc) also ranged from 28.62 mN m^?1 to 34.07 mN m^?1 at CMC level by surface tension experiments. The consequences of the oil/water interface tension experiments indicated that all these prepared surfactants could lower oil/water interface tension to ultra-low with the combination of Na₂CO₃. C₁₂-2-C₁₂, and C₁₄-2-C₁₄ were chosen as the representative to evaluate the displacement efficiency in the oil flooding experiments using authentic sandstone microscopic model. The results showed that these surfactants could effectively improve the displacement efficiency by 10–20%.     

Evaluation of a new alkaline/microbe/polymer flooding system for enhancing heavy oil recovery

The new alkaline/microbe/polymer (AMP) flooding system was first constructed and evaluated for enhancing oil recovery. The system is composed of 0.3?wt% Na₂CO₃, 2?wt% microbial cultures and 0.2?wt% polymer. Compared with the conventional alkaline/surfactant/polymer (ASP) system, the AMP system exhibits identical displacement properties. Chromatography analysis reveals crude oil is not negatively affected by the microbes in AMP system. Further comparative core flooding experiments using the AMP and ASP systems demonstrate that the AMP system possesses greater potential for enhancing heavy oil recovery, which shows the characteristic of two-stage additional oil increment with total additional oil recovery of 17.11%–19.91%.     

Distribution and treatment of harmful gas from heavy oil production in the Liaohe Oilfield,Northeast China

The distribution and treatment of harmful gas (H₂S) in the Liaohe Oilfield, Northeast China, were investigated in this study. It was found that abundant toxic gas (H₂S) is generated in thermal recovery of heavy oil. The H₂S gas is mainly formed during thermochemical sulfate reduction (TSR) occurring in oil reservoirs or the thermal decomposition of sulfocompounds (TDS) in crude oil. H₂S generation is controlled by thermal recovery time, temperature and the injected chemical compounds. The quantity of SO₄²⁻ in the injected compounds is the most influencing factor for the rate of TSR reaction. Therefore, for prevention of H₂S formation, periodic and effective monitoring should be undertaken and adequate H₂S absorbent should also be provided during thermal recovery of heavy oil. The result suggests that great efforts should be made to reduce the SO₄²⁻ source in heavy oil recovery, so as to restrain H₂S generation in reservoirs. In situ burning or desulfurizer adsorption are suggested to reduce H₂S levels. Prediction and prevention of H₂S are important in heavy oil production. This will minimize environmental and human health risks, as well as equipment corrosion.     

Optimization of the Production of Biosurfactant From Iranian Indigenous Bacteria for the Reduction of Surface Tension and Enhanced Oil Recovery

Abstract

The optimum conditions for biosurfactant production by Iran's isolates were examined. The Taguchi method was used to identify nutritional requirements in the medium using four parameters; that is, carbon source, nitrogen, phosphorous, and salt concentrations. The use of whey, oil, and sucrose as carbon sources; NaCl as salt source; (Na₂HPO₄, NaH₂PO₄) as phosphorous source; and (NH₄)₂SO₄ as nitrogen source was examined to determine bacteria optimum conditions. According to the Taguchi method using the sucrose source, the optimal conditions for Bacillus subtilis were 50 g/L NaCl, 13.53 g/L (Na₂HPO₄, NaH₂PO₄), and 1 g/L (NH₄)₂SO₄; for Bacillus cereus they were 25 g/L NaCl, 13.53 g/L (Na₂HPO₄, NaH₂PO₄), and 1 g/L (NH₄)₂SO₄; and for Pseudomonas putida they were 25 g/L NaCl, 13.53 g/L (Na₂HPO₄, NaH₂PO₄), and 1 g/L (NH₄2_SO. Oil displacement experiments in the micromodel at optimum conditions showed around 25% recovery of residual oil with added supernatant of Bacillus subtilis.     

Mechanisms of oil displacement by Geobacillus stearothermophilus producing bio-emulsifier for MEOR

This paper studies the Geobacillus stearothermophilus SL-1 that is widely distributed in oil reservoirs. We also carried out the emulsification stability experiment of paraffin. The particle size distributions of oil-emulsified droplets from the emulsified bacteria and their metabolites were determined by laser particle size analyzer. Using the glass model of the dimensional microscopic visualization, the oil displacement mechanism and effect of the emulsified bacteria on the remaining oil in the simulated reservoir environment were studied. The results show that the emulsified bacteria and their products can effectively emulsify the crude oil, and can form the large emulsion of a big viscosity with the crude oil during oil displacement, which is helpful to increase the flow resistance of the hyperosmotic channel, improve the ratio of oil to water, and enlarge the volume of the injected liquid. The microbial fermentation has a better effect to enhance the recovery than the metabolites or the microbial cell alone, and the oil recovery was enhanced by about 19%. This study has provided new insights and theoretical basis for microbial oil displacement.     

A study of the mechanism of enhancing oil recovery using supercritical carbon dioxide microemulsions

Supercritical carbon dioxide (scCO 2) microemulsion was formed by supercritical CO 2 , H 2 O, sodium bis(2-ethylhexyl) sulfosuccinate (AOT, surfactant) and C 2 H 5 OH (co-surfactant) under pressures higher than 8 MPa at 45 oC. The fundamental characteristics of the scCO 2 microemulsion and the minimum miscibility pressure (MMP) with Daqing oil were investigated with a high-pressure falling sphere viscometer, a high-pressure interfacial tension meter, a PVT cell and a slim tube test. The mechanism of the scCO 2 microemulsion for enhancing oil recovery is discussed. The results showed that the viscosity and density of the scCO 2 microemulsion were higher than those of the scCO 2 fluid at the same pressure and temperature. The results of interfacial tension and slim tube tests indicated that the MMP of the scCO 2 microemulsion and crude oil was lower than that of the scCO 2 and crude oil at 45 oC. It is the combined action of viscosity, density and MMP which made the oil recovery efficiency of the scCO 2 microemulsion higher than that of the scCO 2 fluid.     

Emulsifying action of Pseudomonas aeruginosa L6-1 and its metabolite with crude oil for oil recovery enhancement

Pseudomonas aeruginosa L6-1 was isolated from formation brine of Xinjiang Oilfield, China. Strain L6-1 showed perfect emulsification activity to crude oil and transformed mixture of crude oil and water into emulsion when crude oil was used as sole carbon source; thus, this method is a promising approach for emulsification and mobilization of residual oil in oil reservoirs and enhancement of its recovery. Average diameters of emulsified crude oil were between 1 and 8 µm. Interfacial tension of crude oil and water was reduced to 0.8 mN m^?1. Strain L6-1 produced 2.2 g L^?1 of rhamnolipid biosurfactant. Core flooding tests were carried out to investigate application potential of strain L6-1 for microbial enhanced oil recovery (MEOR). Enhanced oil recovery efficiencies ranged from 9.23% to 12.58% in both core models, with and without oxygen injection. These results revealed that strain L6-1 is a candidate functional microorganism for MEOR application.     

The application of nanofluids for recovery of asphaltenic oil

In the recent years, requirement of suitable enhanced oil recovery (EOR) technique as a more proficient technology becomes significant because of increasing demand for energy. Nanofluids have great potential in order to improve oil recovery. In our study, the effect of SiO₂, Al₂O₃, and MgO nanoparticles on oil recovery was investigated by using core flooding apparatus. Zeta potential and particle size distribution measurements were carried out to investigate the stability of nano particles and results showed SiO₂ has more stability than other ones. Interfacial tension and contact angle measurements between nanofluids and crude oil used to demonstrate that how nanoparticles enhance oil recovery. Experimental data reveals that SiO₂ nanoparticles introduce as the greatest agent among these nanoparticles for enhanced oil recovery. Lowest damage for SiO₂ nanofluids was observed and also it was observed that the concentration and injection rate have straight effects on permeability reductions.     

Optimization of petroleum crude oil treatment using hydrogen sulfide scavenger

Hydrogen sulfide scavenging is one of the preferred methods for minimizing the operational risks and corrosion in crude oil production facilities. This paper deals with the determination of the optimum values of retention times of scavenging hydrogen sulfide from the crude oil produced at different conditions in one of the Egyptian petroleum companies using EPRI H₂S scavenger solution (one of the chemical products of Egyptian Petroleum Research Institute). The retention time depends on several operating condition variables such as injection dose rate, pipe length, pipe diameter, crude oil velocity, pressure and inlet H₂S concentration. The hydrogen sulfide scavenger injected into the crude oil pipeline must be contacted with the crude oil for a suitable a specified time (retention time) to reduce the concentration of H₂S to the desired value which is usually less than 10 ppmv. The optimization results were obtained using the software program LINGO. It was found that the optimum values of H₂S scavenger retention time of the scavenging of hydrogen sulfide are increased by increasing the pipe diameter and the inlet H₂S concentration, while decreased by increasing the pipe length, gas molar mass velocity, injection dose rate, crude oil velocity and pressure.