Efficiency of Ionic Liquid 1-Ethyl-3-Methyl-Imidazolium Acetate ([EMIM][Ac]) in Enhanced Medium Oil Recovery

Chemical flooding is one of the most efficient methods for Enhanced Oil Recovery (EOR). This study demonstrates the efficiency of mixing different concentrations of Ionic Liquid (IL), 1-Ethyl-3-Methyl-Imidazolium Acetate ([EMIM][Ac]), with Weyburn brine to improve a medium oil recovery, Weyburn oil, from an unconsolidated sand pack sample at room conditions. Effects of Slug Size (SS), IL + brine slug initiation time, and combining IL with alkali on the Recovery Factor (RF) were investigated. This study showed that the optimum concentration of ([EMIM][AC]) was 1000 ppm and the most efficient injection time of the chemical slug was at the beginning of the flooding procedure (as secondary flooding mode). In addition, it was proved that the potential of injecting a slug of IL + brine is much better than that of introducing a slug of alkali + brine. Besides, the combination of IL and alkali (AIL) resulted in better RF than injecting either of them alone. Finally, the Surface Tension (SFT), pH, wettability alteration, and viscosity of the displacing phases were measured.

Lag times in toe-to-heel air injection(THAI)operations explain underlying heavy oil production mechanisms

From a time value of revenue point of view,it is preferred that the time between reservoir stimulation and oil production response is small.Heavy oil combustion processes have a lag time between air injection and liquid production,but the common practice in production data analysis uses simultaneous injection and production data when seeking a relationship between them.In this research,the time scales of production for the Kerrobert toe-to-heel air injection(THAI)heavy oil project in Saskatchewan,Canada,is analyzed by using cross correlation analysis,i.e.time delay analysis between air injection and oil production.The results reveal two time scales with respect to production response with two distinctive recovery mechanisms:(1)a short time scale response(nearly instantaneous)where oil production peaks right after air injection(directly after opening production well)reflecting cold heavy oil production mechanisms,and(2)a longer time scale(of order of 100-300 days)response where peak production occurs associated with the collective phenomena of air injection,heat generating reactions,heat transfer,and finally,heated mobilized heavy oil drainage to the production well.This understanding of the two time scales and associated production mechanisms provides a basis for improving the performance of THAI.

Performance and Combustion Characteristics of SINGLE Cylinder Diesel Engine Running on Karanja Oil/Diesel Fuel Blends

The present paper investigates the performance and combustion characteristic of single cylinder, natu-rally aspirated, water cooled, DI diesel engine running on karanja oil (K100) and blends with diesel K10, K15, and K20 and the experimental results were compared with that of diesel. The results showed that the fuel properties of K100, density, viscosity, flash point and carbon residue were found to be higher than that of diesel and calorific value is lower than that of diesel. Based on performance and combustion characteristics of the various blends, the optimum blend was found to be K15.

Research into polymer injection timing for Bohai heavy oil reservoirs

Polymer flooding has been proven to effectively improve oil recovery in the Bohai Oil Field. However, due to high oil viscosity and significant formation heterogeneity, it is necessary to further improve the displacement effectiveness of polymer flooding in heavy oil reservoirs in the service life of offshore platforms. In this paper, the effects of the water/oil mobility ratio in heavy oil reservoirs and the dimensionless oil productivity index on polymer flooding effectiveness were studied utilizing rel- ative permeability curves. The results showed that when the water saturation was less than the value, where the water/oil mobility ratio was equal to 1, polymer flooding could effectively control the increase of fractional water flow, which meant that the upper limit of water/oil ratio suitable for polymer flooding should be the value when the water/oil mobility ratio was equal to 1. Mean while, by injecting a certain volume of water to create water channels in the reservoir, the polymer flooding would be the most effective in improving sweep efficiency, and lower the fractional flow of water to the value corresponding to △Jmax. Considering the service life of the platform and the polymer mobility control capacity, the best polymer injection timing for heavy oil reservoirs was optimized. It has been tested for reservoirs with crude oil viscosity of 123 and 70 mPa s, the optimum polymer flooding effec- tiveness could be obtained when the polymer floods were initiated at the time when the fractional flow of water were 10 % and 25 %, respectively. The injection timing range for polymer flooding was also theoretically analyzed for the Bohai Oil Field utilizing which provided methods for effectiveness. relative permeability curves, improving polymer flooding

低渗砂岩油田CO_(2)驱化学机理及提高采收率研究

针对低渗砂岩油藏进行了CO_(2)驱开发技术研究,分析了CO_(2)驱油化学机理及主要影响因素。基于目标油藏流体特征进行了PVT拟合,确定其CO_(2)驱最小混相压力,明确了不同压力及注入时机对CO_(2)驱采收率、气油比、含水率及驱动压差等的影响规律,探究了CO_(2)泡沫驱在提高采收率方面的效用。结果表明:24.5 MPa为目标区域CO_(2)驱的最小混相压力,采收率会随着压力的升高而增加,28 MPa时CO_(2)驱提高采收率可达30.57%。气体突破时间、总采收率与CO_(2)注入时机密切相关,CO_(2)注入越早,越有利于采收率的提高,出口含水率为60%时注入可提高采收率39.13%。CO_(2)泡沫驱可以在一定程度上起到提高采收率的效用。

稠油开采注汽锅炉在线综合预警关键技术

为了对工作在高温高压下注汽锅炉的各项运行参数进行在线准确监测和异常预警,本文在对稠油开采注汽锅炉工况参数进行采集、处理、分析的基础上,提出对注汽锅炉显性故障和隐性故障进行检测的方案。采用长期短期记忆神经网络,利用锅炉的时序数据对系统进行分析和建模,完成锅炉显性故障检测和预警,并通过预测数据的方式缓解锅炉大时滞的特性;利用深度异常检测技术,将无故障判别标准的数据进行隐性故障分析和预警。本文提出的综合预警方案对克拉玛依油田注汽锅炉进行了实验验证,预测误差仅有0.08%,同时异常检测范围也在设定值范围内。

浅薄层特超稠油油藏冷热交替开采技术研究

针对浅薄层特超稠油油藏蒸汽吞吐开发初期面临的油层厚度薄、原油黏度高、蒸汽热损失大、吞吐有效期短等问题,提出了冷热交替大周期吞吐开发模式,有效改善开发效果。为此开展了浅薄层特超稠油油藏冷热交替开采三维物理模拟研究,结果表明:受顶底盖层热损失影响,蒸汽吞吐温度下降迅速,峰值产量较高,但单周期生产时间较短,约100 min;降黏吞吐可以降低吞吐井附近含油饱和度,提高产油速度,降低含水率,延长吞吐周期50 min以上;提高温度可以增强降黏剂的降黏效果,第二周期开始冷热交替改善效果优于第一周期,其生产时间延长60 min,含水率降低45%,周期采出程度提高1.7%。利用数值模拟方法优化了冷热交替的注入参数,建立了该技术的政策界限:最佳转冷热交替的时机为2~3周期,注入强度为0.02 t/m;适用的油层厚度小于8 m,原油黏度小于200000 mPa•s,含油饱和度大于0.6,渗透率大于1000 mD。

缆控智能分层注水一体化工艺的创新应用

缆控智能分层注水一体化工艺以井下智能测调配水器为核心,集成了流量计、控制电路、电机减速器、可调水嘴和封隔器验封等关键技术。通过实时监测和自动测调控制算法,系统能够精确控制各分层配水器水嘴开度,实现对油田分层注水的数字化和网络化管理。此工艺的关键技术涵盖了注水管柱的设计与功能、地面控制器的组成与功能、井下控制装置如智能测调配水器、高精度流量计和一体化可调水嘴的研发与应用,以及供电和通信电缆的密封与保护技术。实践证明,缆控智能分层注水一体化工艺在提高注水效率、降低人工干预、提升注水合格率等方面表现突出,已在多个油田项目中取得显著成效,大幅度降低了生产成本,提高了油田开发效益。

定子喷油环结构参数对电机散热的影响

采用数值模拟和Pareto Optimality探讨定子中喷油孔数量与孔径对定子内部的流动特性和温度分布规律的影响.研究表明:当喷油孔数量从8个增加到30个时,进出口压降降低了80%,平均湍流度增长了160%,定子铁芯平均温度降低了15%,绕组平均温度降低了16%;孔径从2 mm降低到1.3 mm时,进出口压降增大了57.1%,平均湍流度增长了39.9%,定子铁芯平均温度降低了1.5%,绕组的平均温度降低了2.2%.优化分析得出电机散热效果最优的定子喷油环结构参数范围为:喷油孔数量在20~30个,孔径大小在1.45~1.6 mm.此研究结果对油冷电机散热提供理论依据.

Comparative Assessment of Low-Concentration Ethanol and Waste Fish Oil Biodiesel Blends on Emission Reduction and Performance Improvement in Variable Compression Ratio Engine

The costs of conventional fuels are rising on a daily basis as a result of technical limits,a misallocation of resources between demand and supply,and a shortage of conventional fuel.The use of crude oil contributes to increased environmental contamination,and as a result,there is a pressing need to investigate alternate fuel sources for car applications.Biodiesel is a renewable fuel that is derived chemically by reacting with the sources of biodiesel.The present research is based on analyzing the effect of fish oil biodiesel-ethanol blend in variable compression engine for variable compression ratio(VCR).The processed fish oil was procured and subjected to a transesterification process to convert fatty acids into methyl esters.The obtained methyl esters(biodiesel)were blended with ethanol and diesel to obtain a ternary blend.The ternary blend was tested for its stability,and a stable blend was obtained and tested in VCR engines for its performance,combustion,and emission characteristics.In the second phase,experiments are conducted in the diesel engine by fueling the fish oil methyl ester and ethanol blended with diesel fuel in the concentration of 92.5 vol%of Diesel+7.5 vol%of Fish oil+1.25vol%ethanol,92.5 vol%of Diesel+7.5 vol%of Fish oil+5 vol%ethanol,87.5 vol%of Diesel+12.5 vol%of Fish oil+1.25 vol%ethanol,87.5 vol%of Diesel+12.5 vol%of Fish oil+5 vol%ethanol,82.5 vol%of Diesel+17.5vol%of Fish oil+1.25 vol%ethanol,82.5 vol%of Diesel+17.5 vol%of Fish oil+5 vol%ethanol to find out the performance parameters and emissions.Because the alternative fuel performs better in terms of engine performance and pollution management,the percentage chosen is considered the best mix.The results showed that the use of a lower concentration of ethanol in the fish oil biodiesel blend improved the engine thermal efficiency by 5.23%at a higher compression ratio.Similarly,the engine operated with a higher compression ratio reduced the formation of HC and CO emissions,whereas the NOxand CO_(2)emissions increased with an increased proportion of biodiesel in diesel and ethanol blends.

Inhibition of asphaltene deposition by Al_(2)O_(3) nanoparticles during CO_(2) injection

Carbon dioxide flooding is of interest due to its high oil-sweep efficiency for enhanced oil recovery and contribution to the reduction of greenhouse gas emissions.However,when CO_(2)is injected into deep geological strata,asphaltene may precipitate.In this work,the effect of Al2O3 nanoparticles on the deposition of asphaltene was examined by assessing the variations of bond number and interfacial tension at different pressures and a temperature of 6℃.The asphaltene onset point and intensity were characterized using the bond number,which proved a better indicator of changes in oil droplet shape and interfacial tension with gravity.Synthesized mixtures of toluene and n-heptane that contained two different kinds of asphaltenes were used as M and D oil samples.A 0.06 mass%addition of Al_(2)O_(3) nanoparticles,which worked best for reduction of interfacial tension,was also applied at various pres-sures.Addition of nanoparticles to the oils prevented asphaltene precipitation in both synthetic samples by altering the slope of the plot of interfacial tension with pressure by 49.7% for the M sample and 9.0%for the D sample.The Al_(2)O_(3)nanoparticles were found to be more effective at inhibiting asphaltene precipitation for the M oil sample due to its lower H/C ratio and higher nitrogen content.

丰深1低渗透凝析气藏反凝析污染特征及解除措施实验

丰深1低渗透凝析气藏具有低渗透、易出砂、特高含凝析油等复杂地质和相态特征,开发过程中反凝析污染不可避免,明确反凝析污染特征和建立污染解除措施十分重要。为此,开展了反凝析污染特征及解除措施实验。结果表明:当最大反凝析压力为19MPa时,长岩心气相有效渗透率降幅为90%以上,压裂能提高长岩心气相有效渗透率,但反凝析污染程度尚未明显改善。对于单一注入介质,注CO_(2)解除反凝析污染效果明显优于注甲醇和伴生气;甲醇与CO_(2)等比例混合介质解除反凝析污染效果好于单一注入介质,是最优注入介质。对于注入时机,在19MPa时注CO_(2)后裂缝长岩心渗透率恢复程度最高达61.18%,进一步衰竭至废弃压力时凝析油最终采收率可达36.2%,较5MPa时提高4.9%,较衰竭过程提高7.8%,是相对最优注入时机。

断溶体油藏应力敏感特征研究

断溶体油藏连通介质为裂缝、溶洞、孔隙,随着压力下降导致渗透力下降、导流能力降低,对油井产能产生不可逆的影响。根据断溶体油藏应力敏感特征,设计并开展了72组导流能力物理模拟对比实验,分析了不同连通介质应力敏感特征及其影响因素;基于物理模拟实验结果及和渗流力学理论建立了断溶体油藏流动数值反演模型,开展了储层压力下降导致的应力敏感效应对油井产能的研究。结果表明:压力下降对不同连通介质的导流能力、油井产能以及恢复能力具有较大影响。裂缝型、溶洞型及孔隙型压力拐点出现时机分为原始压力的5.3%、20.4%、35.1%,裂缝型、溶洞型导流能力损失分别为99.7%、45.0%,孔隙型测试范围内未出现走平端。压降拐点特征研究对合理控制产量和能量补充时机的确定提供了依据,对油井稳产具有重要的指导意义。

一次和二次聚合物驱驱替液与原油黏度比优化研究

研究了不同原油黏度原油油藏一次聚合物驱和二次聚合物驱时驱替液与原油黏度比对提高采收率的影响,并对合理黏度比区间进行了优化。研究结果表明:在相同原油黏度条件下,随着黏度比的增大,聚合物驱提高采收率幅度变大,但黏度比大到一定程度后采收率提高幅度的增加不明显;在相同黏度比条件下,二次聚合物驱采收率提高幅度明显低于一次聚合物驱,如果要达到一次聚合物驱时的采收率提高幅度,则需要较高的黏度比;二次聚合物驱时,聚合物注入时机越早越好。绘制了合理黏度比的理论图版,利用该图版可以检验矿场实施单元注入参数的合理性,且为一次聚合物驱及二次聚合物驱的合理注入参数设计提供了依据。

高含水阶段重新认识水驱油效率

通过实验和理论分析,从影响水驱油效率的主要内在和外在因素出发,分析高含水阶段水驱油效率变化的可能性。内在因素主要包括储集层的非均质性(尤其是微观孔隙结构的非均质性)、润湿性等;外在因素主要为水驱条件,包括注水孔隙体积倍数、注入速度及油水黏度比等。根据水驱油效率的定义、实验室测定及矿场应用情况,尝试分析水驱油效率变化的机理,提出了高含水阶段储集层润湿性及孔隙结构变化将导致临界毛管数的降低,使残余油饱和度减小,进而提高水驱油效率。水驱油田进入高含水开发阶段后应加强对水驱油效率的关注,从3个层次加深对水驱油效率的研究,首先是水驱油效率的实验取值,其次要研究不同储集层水驱油效率的经济界限,最后要从毛管数出发,着眼于经济有效地提高水驱油效率的技术研究方向。

聚合物驱后进一步提高采收率途径的研究

通过聚合物驱前、后钻取的密闭取心井资料,研究聚合物驱后油层剩余油的分布特征,分析其挖潜机理,探索聚合物驱后进一步提高采收率的途径,并研究其注入时机。研究结果表明,聚驱后剩余油饱和度在40%左右,在纵向上主要分布在沉积单元顶部和发育较差部位,在平面上主要分布在主流线两翼;泡沫复合驱和蒸汽驱是聚合物驱后提高采收率的主要途径和方法;水驱后直接泡沫驱或蒸汽驱和水驱后聚合物驱,然后再泡沫驱或蒸汽驱,虽然两者含水变化不一样,但采收率提高值相差无几。

一类典型油藏注聚时机研究

聚合物注入时机会影响水驱后提高石油采收率效果。针对中孔、中渗、强非均质性这一类典型油藏,运用数值模拟与物理模拟实验相结合的方法,研究了注聚时机对聚合物驱油效果的影响规律。结果表明,对于中孔、中渗、强非均质性油藏,在实际矿场生产时间内,注聚时机越早,原油采收率越高。在不同的含水率阶段,注聚时机对提高原油采收率效果影响不同;在极限开采情况下,采收率随注聚时机延迟,几乎呈单调递减趋势。早期注聚可以延长无水采油期。注聚时机越早,采油速度越大。

压裂-注氮原位裂解油页岩加热工艺及传热模拟

提出了一种油页岩地下原位转化的新方法,即压裂-注氮原位裂解油页岩技术.油页岩储层压裂后,在加热井内下入电加热器,然后向井内注入氮气,利用加热后的高温氮气原位裂解油页岩.介绍了该方法与传统的电加热法和对流加热法相比的优势,以及特别适用的地层,并且对加热氮气过程进行了传热模拟,优化了气体加热器的参数,确定加热器的最佳长度为30 m,其热流密度为11 k W/m2.针对本工艺方法特别适用的薄层油页岩地下原位开采,进行了地层加热时间的传热模拟,确定了80 d即可将井距15 m,矿层1.5 m厚的油页岩加热到裂解温度,较电加热法和对流加热法的加热时间明显缩短.

海上稠油油藏早期注聚压力与注聚时机研究

渤海油区属于典型的海上稠油油藏,目前水驱采收率不高,聚合物驱提高采收率潜力较大。鉴于海上油田开发平台寿命的时效性和开发投资的风险性,使得海上稠油油藏早期注聚时机和注聚压力特征不同于陆地油田中后期注聚。利用数值模拟手段和油藏工程方法,研究了渤海油区典型常规稠油油藏早期注聚压力特征、注聚时机及其影响因素;利用中心组合实验设计方法,建立了早期注聚压力变化与其影响因素之间的关系式。结果表明:海上稠油油藏早期注聚压力受5个因素影响,影响程度由大到小依次为聚合物溶液粘度、油藏渗透率、注入速度、注聚时机和原油粘度;注聚时机受原油粘度和油藏渗透率制约,原油粘度越大、油藏渗透率越低,注聚时机则越晚,渤海油区稠油油藏早期注聚的合理时机在含水率大于20%以后,极限注聚时机在含水率为10%。

稠油减氧空气泡沫驱注入参数优化及现场应用

针对鲁克沁稠油油藏泡沫驱开采存在的气锁、注入参数不合理等问题,通过物理模拟实验,对减氧空气泡沫驱注入参数进行了优化。研究表明:水驱突破时开展减氧空气泡沫驱,采出程度增幅最高,含水率明显下降;采用气液交替注入方式替代气液同注方式,可避免井筒内气液分离和腐蚀问题,且当减氧空气和发泡液的单次注入量为0.1倍孔隙体积时,驱替效果与气液同注效果相当。室内获得的最佳注入参数为:水驱含水率达70%时转泡沫驱,液和气交替注入,单次注入0.1倍孔隙体积,注入速率为0.3 mL/min。现场施工参数调整后,试验区日增油为42 t/d,含水率下降28个百分点,累计增油为1.4×10^4t,产水量降低2.65×10^4m^3。现场试验证明,减氧空气泡沫驱优化方案切实可行,该成果为鲁克沁稠油规模开发提供了重要技术支持。