Experimental measurements of water content in crude oil emulsions by terahertz time-domain spectroscopy

We measured the water content （0.01% 0.25% w/w） in crude oil emulsions using terahertz time-domain spectroscopy （THz-TDS）. To improve the precision and range of the measurements, we used 1 and 10 mm thick quartz cells. The experiments were performed at 20 ℃ and the THz wave was transmitted vertically to the samples and detected on the other side. The experimental results suggest linear relation for the THz absorption coefficient and the water content of the crude oil emulsions in the observed range. The linear dependence facilitates high-precision measurements of the water content of crude oil. This suggests the potential of THz-TDS in determining the water concentration in crude oil and borehole fluid identification.

Method of Predicting Water Content in Crude Oil Based on Measuring Range Automatic Switching

Water content in output crude oil is hard to measure precisely because of wide range of dielectric coefficient of crude oil caused by injected dehydrating and demulsifying agents.The method to reduce measurement error of water content in crude oil proposed in this paper is based on switching measuring ranges of on-line water content analyzer automatically.Measuring precision on data collected from oil field and analyzed by in-field operators can be impressively improved by using back propogation （BP） neural network to predict water content in output crude oil.Application results show that the difficulty in accurately measuring water-oil content ratio can be solved effectively through this combination of on-line measuring range automatic switching and real time prediction,as this method has been tested repeatedly on-site in oil fields with satisfactory prediction results.

Impact of emulsification of crude oil on normalized radar cross section

The emulsification of crude oil is caused by the oil flowing into the water,resulting in the increase of oil film tension,viscosity,water content,and volume,which brings great harm to the marine ecological environment and difficulties for the cleanup of marine emergency equipment.The realization observation of emulsification crude oil will increase the response speed of marine emergency response.Therefore,we set up crude oil emulsification samples to study the physical property in laboratory and conducted radar measurements at different incidence angles in outdoor.The radar is C band in resolution of 0.7 m by 0.7 m.A fully polarimetric scatterometer(HH,VV,and VH/HV)is mounted at 1.66 m(minimum altitude)height at an incidence angle between 35°and 60°.An asphalt content of less than 3%crude oil and the filtered seawater were used to the outdoor emulsification scattering experiment.The measurement results are as follows.The water content can be used to describe the process of emulsification and it is easy to measure.Wind speed,asphalt content,seawater temperature,and photo-oxidation affect the emulsifying process of crude oil,and affects the normalized radar cross section(NRCS)of oil film but wind is not the dominant factor.It is the first time to find that the emulsification of crude oil results in an increase of NRCS.

Terahertz-dependent evaluation of water content in high-water-cut crude oil using additive-manufactured samplers

The evaluation of water content in crude oil is of significance to petroleum exploration and transportation.Terahertz(THz) waves are sensitive to fluctuations in the dipole moment of water.However,due to the strong absorption of water in the THz range,it is difficult for the THz spectrum to determine high water content with the common sampler.In this research,micron-grade samplers for THz detection were designed and manufactured using additive manufacturing(AM) technology.Oil-water mixtures with water content from 1.8%to 90.6%were measured with the THz-TDS system using sample cells.In addition,a detailed analysis was performed of the relationships among THz parameters such as signal peak,time delay,and refractive index as well as absorption coefficient and high water content(>60%).Results suggest that the combination of THz spectroscopy and AM technique is effective for water content evaluation in crude oil and can be further applied in the petroleum industry.

The effect of water content in crude oil on the tribological behavior of screw pump's stator rubber

It is worthy of studying the effect of water content in crude oil on tribological behavior of stator rubber,because the different water content would affect the swelling and wear of rubber.Compatibility of dewatered crude oil and water was observed after mixture of dewatered crude oil and water(called oil-water mixture)was mechanical stirred and statically placed.Static etching experiment of samples in oil-water mixture was performed using hanging patch test.Wetting contact angle of oilwater mixture on rubber surface was measured by contact angle meter.Tribological behavior of samples in mixture was measured using a ring-on-block tester.The result shows that when the water content is less than 15%,water can blend with dewatered crude oil,and oil-water separation happens when water content was more than 15%.With the increasing of water content in crude oil,Wettability of mixture and swelling increment of samples decrease.The wear loss of sample increases after treated by swelling experiment,and FKM owns better wear resistance than NBR.

同心双锥型高含水油水两相管式旋流分离特性

针对常规切向入口旋流分离器处理高含水采出液效果较差以及分离效率受入口流速影响较大等问题,率先提出中心细锥体和外筒倒锥体的同心双锥型油水两相管式分离构造。综合高含水率、大处理量等因素综合作用,建立油-水两相分离Mixture多相流模型和流场RNG k-ε湍流模型,并采用SIMPLE压力-速度耦合算法对模型进行求解,依据求解结果揭示同心双锥型管式分离腔室内旋流场的动态分布状况,量化分析中心锥角度变化对油水两相管式分离效率的具体影响程度,探究油滴粒径、入口流速等参数对管式旋流分离性能的作用机制。结果表明,随中心锥角度不断增加,同心双锥型管式旋流分离效率呈现先升高再降低的变化趋势,最佳中心锥角度为82°;增大油滴粒径能升高油池聚集性,有利于提升分离性能,当油滴粒径由0.3 mm增至0.6 mm时,分离效率由85.6%提至94.5%;入口流速对分离效率的影响相对较小,当入口流速由5 m·s^(-1)提至11 m·s^(-1),分离效率仅由93.3%升至96.9%,流速相差6 m·s^(-1)时,分离效率仅相差3.5%。

处理站间含水原油输送参数优化

“分水站+脱水站”是油田广泛应用的采出液处理模式之一,实现多站整体节能,需要对处理站和管道进行整体优化。基于进站温度对脱水和外输能耗的影响建立了含水原油输送热能损耗计算方法,在分水站、脱水站和管道的整个系统中,分析出含水原油处理及输送的能耗,研究了分水站外输原油含水、温度等参数对系统能耗的影响。结果表明:原油含水增加,原油输送热能损耗先增加后降低,油水反相点是热能损耗最大的含水工况;外输温度升高,原油输送热能损耗增加;在低温高含水时,原油输送热能损耗较低;原油含水增加,分水站原油外输压力降、压力能损耗和综合能耗先升高后降低,然后再升高,存在低含水和较高含水两个压力降、压力能损耗和综合能耗极小值,含水率70%时综合能耗最低;分水站低含水原油外输,或者反相点以上的高含水外输,都能达到节能降耗目的。当扩建受到限制或改造成本高时,分水站宜利用地层热能进行不加热油水分离,原油外输含水宜高于反相点含水。

低成本低油水比低土相油基钻井液技术研制与应用

油基钻井液的应用范围较广,为降低油基钻井液成本,通过优选低成本油类基础液,开展研发新型单剂高效乳化剂,降低油水比,降低有机土加量等研究,建立了新型低成本低油水比低土相油基钻井液配方,同时对其性能进行了室内评价。实验结果表明:该钻井液油水比在65∶35~85∶15范围可调,有机土加量小于等于2.0%,密度为1.4~2.2 g/cm^(3),抗温达200℃,破乳电压大于800 V,高温高压失水量小于3 mL,油基钻井液单方成本较3号白油配制的油基钻井液降低15%以上,适用于-25℃条件,可满足辽河油区冬季施工需求。在辽河油区页岩油、致密油地层进行了应用,现场应用结果表明,低成本低油水比低土相油基钻井液性能稳定,封堵防塌性能良好,乳化稳定性良好,耐低温效果好,单方成本明显降低。研究成果有利于油基钻井液应用规模的扩大,可满足非常规油气资源低成本、安全、高效开发的技术需求。

高含H_(2)S和CO_(2)环境下原油集输管道的腐蚀规律研究

原油中H_(2)S和CO_(2)会对管壁产生腐蚀破坏,研究其腐蚀规律可为现场人员制定防治措施提供指导。以长庆油田某原油管道为研究对象,建立了高含H_(2)S和CO_(2)原油管道腐蚀模型,分析了不同因素变化对管道腐蚀规律的影响。结果表明:在现场管道维护与巡检过程中,应着重注意入口端、出口端下降段、出口端爬坡段中部管壁的腐蚀情况;当原油H_(2)S和CO_(2)含量较高时,其含量变化对管道沿程腐蚀状况影响很小;随着原油输送流量的增加,管道沿程腐蚀速率均有一定程度的增大;流体温度在20℃至70℃区间变化对管道沿程腐蚀速率的影响较小,但温度升高至80℃后可有效降低管道的腐蚀速率;原油含水率(体积分数)在10%至70%区间内变化对管道腐蚀速率的影响很小,当原油含水率(体积分数)达到90%后,管道沿程各处腐蚀速率大幅降低。

油田老化油处理工艺研究及应用

随着海上油田群滚动开发,南海西部某陆岸终端老化油逐步增多,老化油不仅占据大量罐容,还影响外输销售原油产品质量。针对老化油含水率高、乳化程度高和机械杂质含量高特点,因地制宜通过新增一套蝶式离心机并利用现有设备设施进行工艺流程适应性改造,采取离心机离心分离预脱水、事故罐热化学沉降再脱水和原油稳定塔高温蒸馏精脱水三段处理工艺进行处理。通过该处理工艺,已累计处理老化油3万m3,处理后原油含水率≤0.5%,满足原油外输销售标准,应用效果良好。

Experimental research on oil fi lm thickness and its microwave scattering during emulsifi cation

Synthetic Aperture Radar(SAR) plays a major role in identifying oil spills on the sea surface.However,obtaining information of oil spill thickness(volume) is still a challenge.Emulsification is an important process affecting the thickness and normalized radar cross section(NRCS) of oil film.Experiments of crude oil emulsification with C-band fully-polarized scatterometer were conducted combining airborne hyperspectral imaging spectrometer and 3 D laser scanner observation data,to provide experimental parameters and method to support accurate remote sensing monitoring on marine oil spill.It is further proved that through quantitative homogeneous emulsified oil spill experiments,to a certain extent,the NRCS of oil film increased during the emulsification process of crude oil.The backscattering mechanism of crude oil emulsification was explored using a semi-empirical model(SEM);the change of oil film NRCS was modulated by its dielectric constant and surface roughness,in which the dielectric constant showed a dominant effect.The relationship between thickness and NRCS of oil film was studied under two experimental conditions.The differences of NRCS between oil film and adjacent seawater(Δσ~0) and the damping ratio(DR) were found to have a linear relationship with oil thickness,which were best in the vertical polarization mode(VV) at 45° incident angle during the quantitative crude oil homogeneous emulsification process.In the natural emulsification process of continuous oil spill in which oil film was mixed with both crude oil and emulsified oil,an empirical equation of oil film thickness is preliminarily established.The Δσ~0,DR,and the empirical equation of oil film thickness were applied to the marine continuous oil spill incident on a 19-3 oil platform with spaceborne SAR image and successfully explained the distribution of the relative thickness of the oil film.

基于Vivaldi天线的原油含水率测量仪设计

微波透射法原油含水率测量仪设计的关键点是微波传感器的小型化,即要求微波传感器的辐射口径面必须小于油管的内径。为解决这一技术难题,一种辐射口径面为70 mm×2 mm的Vivaldi天线被提出,由于该天线的2 mm厚度远小于油管内径,因此可应用于任意尺寸油管进行含水率测试,非常符合微波透射法含水率的测试需求。通过测试结果可以看出:所设计的Vivaldi天线工作频带为2.5~8 GHz(工作带宽为110%)。将所设计的Vivaldi天线应用于微波透射法原油含水率测量仪作为微波传感器,分析传输系数与含水率之间的变化关系。测试结果表明:Vivaldi天线在0~100%范围内测试的绝对误差小于7%,而在10%~85%范围内绝对误差小于5%。该实验结果,为以后测量系统实现含水率的高精度测量和在线测量提供理论依据和实际参考。

毂辐式多点油品采样器的研制与应用

在原油管输交接计量过程中,如何持续监测原油含水率,并确保测量数据的准确性是一项技术难题.根据原油取样代表性要求和管道截面含水率不均匀的情况,研发了毂辐式多点油品采样器,介绍了该采样器的结构和工作原理,通过实际应用表明,该采样器可均匀获取输油管道截面各位置的原油试样,所收集数据能够客观反映流体分布状态,值得推广应用.

新型原油含水率及密度智能在线分析系统应用总结

新型原油含水率及密度智能在线分析系统基于微波共振原理,配置在线组分自动修正功能,适用于进口原油和国产原油,免维护,无周期性清洗需求。首套分析系统将含水分析仪安装在主管,后为了提升油水混合效果,改为旁路安装。在确保油水混合均匀的前提下,当含水率低于1%时,测量不确定度小于±0.05%;当含水率在1%~20%时,测量不确定度小于读数的±5%;当含水率在20%~50%时,测量不确定度小于±1%;当含水率在50%~100%时,测量不确定度小于±5%;密度测量不确定度为±0.2 kg/m^(3)。应用表明,该系统在管输原油的计量交接或监督、电脱盐进料和常减压进料的实时监控等方面具有良好的应用前景。

原油含水率增加对海上油田注汽锅炉运行的影响

受原油含水率增加的影响,海上油田注汽锅炉经常出现排烟温度升高、燃烧器结焦和换热管路腐蚀加剧等问题。为了保障海上油田注汽锅炉的运行性能,本文对锅炉积灰物和原油含水率进行了化验分析,本文以详细的计算和运行数据为依据,揭示了原油含水率升高对锅炉运行性能的影响规律。研究发现原油含水率增大后,Na^(+)离子和Cl^(-)离子含量增多。盐分在换热管路上凝结后,加速了换热管道的腐蚀过程,并降低了换热管道的换热效率,进一步引起注汽锅炉排烟温度升高。当原油含水率增加至10%时,其低位发热量降低了9.7%,粘度增加了1.39倍,注汽锅炉排烟热损失增加了16.9%。

大型原油站库控制外输原油含水措施

华北油田任一联合站日外输量6000 t,总储油能力22.5万m 3,负责接收处理冀中地区原油,是华北油田公司规模最大的储油站库。随着原油外输交接质量日益严格,之前降低原油外输含水操作不能满足生产运行要求。为此,对大型原油库平稳生产运行和外输原油质量把控进行了研究分析。针对冬季任一联合站出现的高含水采取了应对措施,实施后取得了良好效果,外输净化油质量得到提升,日外输平均含水下降了0.2%,降低了生产成本,实现了安全平稳输油。

油管钢在饱和二氧化碳模拟油田液中的腐蚀研究

利用自制压力釜 ,通过失重法 ,分别研究了静态及动态条件下不同原油 /水介质含量 (体积 )比对油管钢在CO2 饱和的模拟油田液中的腐蚀影响 ,并通过环境扫描电镜、能谱、X -ray衍射及X射线光电子能谱对腐蚀产物膜的形貌、结构及组成进行了分析 .结果表明 :原油 /水介质含量比对阴极析氢反应有显著影响 ,与CO2 腐蚀速率的关系是 :动态条件下 ,水介质含量为 70 %时 ,腐蚀速率出现波谷 ;动、静两种条件下 ,水介质含量为 5 0 %时 ,腐蚀速率各自出现一个波峰 .腐蚀产物膜中含有复盐 (Mn ,Fe)CO3 、(Ca,Mn)CO3 及 (Ca ,Mn ,Fe)CO3 ,腐蚀产物为FeCO3 ,在空气中不稳定 ,发生分解 ,最终生成Fe2 O3 .

原油储罐油水界面动态检测系统的研究

设计了油水界面动态检测系统.利用数控执行机构带动微波探头在原油储罐内作垂直匀速运动,通过对原油储罐含水率的动态检测,准确地反映出油水乳化带的状态和位置信息,测量出储罐内油水界面的位置,从而确定储罐内原油、水和乳化液层的位置和体积.采用400 MHz激励信号的微波探头,可实现0～100%原油含水率的动态测定,含水率测量误差≤±2%.在20 m范围内,油水界面的位置测量误差小于±10 mm.

乳化剂HC-5的性能及驱油效果

针对国内老油田的开发现状,对设计的乳化剂配方体系进行了基本性能评价和乳化驱油效果研究,探讨了乳化驱油的可行性和驱油机理。研究结果表明,优选的乳化剂配方体系HC-5(氨基磺酸型两性活性剂20%,OP系列非离子表面活性剂8%,稳定剂0.8%,助溶剂2.5%,其余为水)具有良好的耐盐抗盐性能,在室温数85℃范围内、盐度超过120 g/L的混合盐水中的溶解性良好;HC-5能在高、中和低盐度的盐水中有效乳化原油,并具有良好的乳化稳定性;HC-5乳化体系的乳状液类型与盐度和含水率有关,盐度增加时,发生W/O型乳状液向O/W型转变的临界含水率增大,矿化度为15350 mg/L、40650 mg/L和120670 mg/L的体系的临界含水率分别为48%、57%和68%。室内模拟乳化驱油试验表明,乳化驱对于低渗透驱替介质有明显增压和调剖作用,波及系数增大,原油采收率提高;而对于较高渗透率的驱替介质,乳液的调剖机理和表面活性剂驱油机理共同作用实现了原油采收率的提高。

原油含水率测量技术现状与发展

原油含水率是原油的一项重要指标,目前对于原油含水率的测量方法有很多。主要介绍国内外原油含水率测量的主要方法,测量原理,适用环境,各自的优缺点,方法的改进措施,以及原油含水率测量的发展趋势,为含水率测量方法的选择提供参考。