热处理作用对含蜡原油流变性的影响

热处理技术是改善含蜡原油低温流动性的一种主要方法,以BH油田含蜡原油为例,通过一系列热处理试验对含蜡原油进行了流变性能研究,对实验数据进行了理论分析,并结合现场应用情况验证了试验结论的正确性。分析结果表明：温度是影响热处理效果的主要因素,中温段（50～60℃）的热处理会对含蜡原油的凝点产生恶化效果;高温段（70～95℃）的热处理可以大幅降低含蜡原油的凝点。冷却速度对含蜡原油热处理效果的影响至关重要,当冷却速度较小（0．5～1．0℃／min）时,油样热处理效果较好;冷却速度太快（1．2～1．5％／min）,将使热处理效果变差。剪切速率对热处理效果有一定影响,通常在较低速率的剪切作用下,原油热处理效果较好,随着剪切速率的增加,原油热处理效果变差。热处理后油样的稳定性对热处理效果的影响也不可忽视。     

延长定靖含蜡原油管线加热输送流动特性研究

针对延长定靖含蜡原油管线清管周期频繁的运行问题，以延长油田含蜡原油为研究对象，利用实验分析，测量原油组分、物理性质和流变性，确定了最佳热处理温度及流变特性；为准确分析管线的温降与压降，采用实验与理论分析相结合开展研究，以最佳热处理温度为首站管输温度进行分析。研究表明，原油最佳热处理温度为75℃、析蜡点为51℃、反常点为32℃,获得热处理后全线的温降、压降特性，确定管输最优热处理温度及在最优热处理温度下管输流动特性。研究成果为含蜡原油管道的安全可靠运行提供实验支撑与科学依据。     

江苏油田B1断块原油降凝剂研究

江苏油田B1断块原油属于高含蜡、高胶质、高沥青质原油,具有高凝、高黏特点,平均凝固点41.5℃、析蜡点59～60℃,温度敏感性强。针对该区块原油特性,开展井筒降凝、降黏工艺和配方研究,进行了降凝降黏剂的评价和配比,优选了合成的复配型降凝剂KD-50（Ⅳ）,确定合理添加浓度,考察在不同温度下对B1断块原油的降黏效果。室内实验结果表明：添加降凝降黏剂后,低温流动性明显改善,凝点、反常点和低温表观黏度均有较大幅度降低,在40℃加剂后的降凝降黏率达80%以上,具有较好的推广应用价值。     

旅大原油降凝剂的研究

针对旅大原油高含蜡特性,比较了本实验优选合成的EVA改性型降凝剂ZLX-01与市售7种降凝剂对旅大原油的降凝效果,并探讨了影响加剂效果的因素。实验结果表明,旅大原油最佳热处理温度为50～55℃,降凝剂ZLX-01最优加剂量为300 mg/L,原油凝点由加剂前的22℃降至9℃,反常点由加剂前的35℃降至30℃。在原油温度25℃、剪速12 1/s下,加入300 mg/L的降凝剂ZLX-01后,原油表观黏度由加剂前的420 mPa.s降至116 mPa.s,降黏率为72.4%。重复加热温度低于40℃时会恶化加剂原油的低温流变性,此外加有ZLX-01的原油还具有较好的静态稳定性。图2表4参2     

高凝油油藏自生热压裂液技术在河南油田的应用

河南油田高凝油油藏原油有含蜡高、凝固点高、低含硫的特征,压裂施工中,进入地层的工作液对地层有冷却作用,对于高含蜡、高凝固点的原油,工作液的冷却作用就会造成地层温度低于析蜡温度,使蜡、胶质沥青质析出,堵塞出油孔道,严重影响压裂增产效果。针对高凝油油藏注入流体易造成冷伤害的问题,开展高凝油油藏自生热压裂液体系的研究,研究出胶囊包裹催化生热压裂技术,现场应用2口井,取得较好的效果,可为类似作业提供参考。     

濮城原油热处理中加入降凝剂之研究

含蜡原油常温输送是迫切需要解决的问题.采用热处理和使用由降凝剂EVA与油溶性表面活性剂202B组成之复配剂的综合处理方法处理濮城原油,获得令人满意的结果.加入100～300ppm复配剂,原油的凝固点最佳时可降低23～27℃,表观粘度减小至200×10~(-3)帕斯卡秒(10℃,剪速24.3秒~(-1))以下,其低温流动性得到明显改善,加复配剂前后,原油的流变性变化较大.此外,对热处理温度、冷却方式、终冷温度以及添加剂溶液浓度等处理条件的影响进行了考查.在试验过程中发现"表面凝固"现象.     

江汉原油添加剂降凝及热处理降凝初步研究

本文介绍了含蜡原油添加剂及热处理降凝方法,用降凝剂EVA、Paradyne-70及Shellswirn-5T在适当的条件下可将江汉原油凝固点降低7～16℃,文中分别对添加剂及热处理降凝机理进行了论述,介绍了实验条件及影响降凝效果的因素,为工业应用提供了依据。     

降凝剂对中哈管输阿拉山口口岸多蜡原油流变性的影响

筛选了适合改善中哈管输阿拉山口口岸含蜡原油流变性的降凝剂,考察了加剂前后全黏温曲线的变化及重复加热、高速剪切对原油黏度和凝点的影响,并考察了静置稳定性。实验结果表明：在60 ℃处理温度下加入50 g/g乙烯-醋酸乙烯酯和丙烯酸接枝共聚物作为降凝剂,可使原油的凝点降低10~20 ℃以上,黏度、反常点、屈服值均有明显降低;重复加热温度低于60 ℃,随温度的降低原油改性效果变差;高速剪切对降凝剂降凝效果的影响与温度有直接关系,在析蜡高峰区温度附近降凝效果恶化严重;降凝剂对原油的静置稳定性表现较好。     

高蜡原油管输用高效降凝剂的筛选及降凝降黏性能评价

针对我国中部某油田高含蜡(31.60％)、高凝点(37℃)、高黏度原油,考察了原油降凝剂YG-1,YG-2,YG-3,YG-4,YG-5,YG-6,BEM,EVA2503,EVA28/150,EVA2803的降凝降黏性能,筛选出对该原油具有较好适应性的降凝剂YG-1,并考察降凝剂浓度、热处理温度及重复加热对YG-1降凝降黏效果的影响.结果表明,热处理温度65℃时,YG-1浓度50 mg/L下,原油凝点降低了15℃,原油黏度(30℃,50 s-1下测定)由1770.0mPa·s降至608.2 mPa·s;重复加热对该原油低温流动性影响较小,降凝剂稳定性较好,能实现原油在当地地温下常温输送.     

江汉原油热处理与降凝剂综合降凝的研究

本文考察了采用热处理和使用化学降凝剂EVA的综合处理方法对江汉原油的降凝、减粘效果。发现热处理时加入EVA200ppm即可降低凝固点15～16℃，表观粘度减少至51．0×10^3Pa·s（30℃，553．4s-1），流变性能得到明显改善。比外，还考查了降凝剂的加量、热处理温度，冷却方式及降凝剂分子量等因素对降凝、减粘效果的影响。确定了江汉原油综合处理时的最佳热处理温度及降凝剂的加量。     

关于我国含蜡原油热处理问题

本文就原油热处理技术在节能方面的作用和效果做了评价,并在以往实验研究工作的基础上,着重总结了含蜡原油热处理的一些规律性认识.     

LOW TEMPERATURE FLOW CHARACTERISTICS OF SOME WAXY CRUDE OILS IN RELATION TO THEIR COMPOSITION : PART II EFFECT OF WAX COMPOSITION AND CONCENTRATION ON THE DEW AXED CRUDE OILS WITH / WITHOUT ADDITIVES

In this part of the work the effect of wax concentrations on the rheologica! properties of the dewaxed Duliajan (Assam) and Lingaia crude oils have been studied. The dewaxing of the crude oil was done by removing n-paraffins from the crude oil by urea adduction. The urea adducted n-paraffins concentrate-the wax- was characterized by its carbon number distribution. The urea non adducted oil portion - the denormalized crude oil (DNO)- was characterized for its pour point. The wax in different concentration was then added in the DNO and the change in the rheological properties like pour point, yield stress and plastic viscosity were studied using a Haake Rota Viscometer. The effect of carbon number distribution, i.e. the composition of the wax, on these rheological properties was also investigated. Four different commercial pour point depressanl additives have been used to study their effects on the pour point, yield stress and plastic viscosity of the reconstituted (wax mixed DNO) crude oils.

From this study it has been found that wax concentration and its composition are primarily responsible for the variation in the pour point of the DNO, and the DNO composition has a small effect. However, as seen in the Part I of this paper, the response of the pour point depressant additive in effecting the change in the pour point is primarily governed by the composition of the DNO. The additives have shown better response in the DNO having more aromatic concentrate, as has been found in the case of Duliajan (Assam) DNO.     

环庆原油黏温曲线测定研究

为更好地研究原油黏温关系和蜡沉积状况,以环庆原油为研究对象,探讨分析了试验室热处理温度、剪切速率和升降温程序等因素对环庆原油黏温曲线、析蜡点及溶蜡点测定的影响。室内试验结果表明:热处理温度对环庆原油的析蜡点、溶蜡点有较大影响,高温可以显著改善原油低温流动性,但热处理温度过高、恒温时间过长时热处理效果变差;环庆原油溶蜡点比析蜡点高7~11℃左右;测定过程中,在析蜡高峰区附近要避免高速剪切和剪切时间过长;析蜡点测定中降温速率不易控制;溶蜡点在凝点之后的低温区测定结果不稳定。     

一种新型原油降凝剂的研究

由乙烯、醋酸乙烯酯和乙烯醇聚醚组成的三元共聚物(WHP)是一种新型高分子表面活性剂型原油降凝剂.这种原油降凝剂既具有聚合物的特点,又有一定的表面活性,与某些常用的降凝剂,如EVA、聚丙烯酸高碳醇酯等相比,这种降凝剂无论对含高碳蜡(C₃₇-C₆₃)的吐哈原油和新疆混合原油,还是含一般蜡的江汉原油、鲁宁线原油和中洛线原油均表现出良好的降凝效果.例如,对吐哈原油在加药量为50mg/l时,一般原油降凝剂没有降凝效果,而WHP可以将原油凝固点从17℃降至10℃;而对新疆混合原油,当加药量为20mg/l时,WHP可以将原油凝固点从11℃降至-15℃而一般最好的降凝剂只能降至-8℃,即使对凝固点比较高的江汉原油,当加药量为100mg/l时,一般降凝剂只能将原油凝固点从34℃降至22℃,而WHP则可降至14℃.此外,WHP对鲁宁线原油还有一定的降粘效果,在加药量为40mg/l时,在30℃测定的降粘幅度为25.2%,而一般降凝剂最大的降粘幅度为14%.在室内模拟鲁宁线原油流动的情况下,原油加入WHP后依次经过多次慢速(80r/min)和快速(1500r/min)搅拌剪切后,原油凝固点回升幅度有较大的降低,且粘度的回升幅度也有所改善.     

LOW TEMPERATURE FLOW CHARACTERISTICS OF SOME WAXY CRUDE OILS IN RELATION TO THEIR COMPOSITION : PART II EFFECT OF WAX COMPOSITION AND CONCENTRATION ON THE DEW AXED CRUDE OILS WITH / WITHOUT ADDITIVES

ABSTRACT

In this part of the work the effect of wax concentrations on the rheologica! properties of the dewaxed Duliajan (Assam) and Lingaia crude oils have been studied. The dewaxing of the crude oil was done by removing n-paraffins from the crude oil by urea adduction. The urea adducted n-paraffins concentrate-the wax- was characterized by its carbon number distribution. The urea non adducted oil portion - the denormalized crude oil (DNO)- was characterized for its pour point. The wax in different concentration was then added in the DNO and the change in the rheological properties like pour point, yield stress and plastic viscosity were studied using a Haake Rota Viscometer. The effect of carbon number distribution, i.e. the composition of the wax, on these rheological properties was also investigated. Four different commercial pour point depressanl additives have been used to study their effects on the pour point, yield stress and plastic viscosity of the reconstituted (wax mixed DNO) crude oils.

From this study it has been found that wax concentration and its composition are primarily responsible for the variation in the pour point of the DNO, and the DNO composition has a small effect. However, as seen in the Part I of this paper, the response of the pour point depressant additive in effecting the change in the pour point is primarily governed by the composition of the DNO. The additives have shown better response in the DNO having more aromatic concentrate, as has been found in the case of Duliajan (Assam) DNO.     

胺解聚合物型原油降凝剂的合成及应用

通过丙烯酸高碳酯与马来酸酐、醋酸乙烯酯、苯乙烯共聚后进行不同系列胺解得到一系列新型高蜡原油降凝剂。考察了该类降凝剂对大庆高蜡原油和尼尔阿曼混合原油的降凝效果。结果表明，胺解聚合物型原油降凝剂具有较好的原油降凝性能，降凝幅度最高达到27℃；同时，测定了加剂温度对降凝剂降凝效果的影响，结果发现，当加剂温度高于原油析蜡温度时，降凝剂的降凝效果才能充分显现出来。     

超临界CO2处理对长庆原油添加降凝剂效果的影响

利用超临界CO2(scCO2)与原油混相处理装置,模拟地层条件对长庆原油进行超临界CO2混相处理,通过对处理前后油样的四组分(SARA)、沥青质稳定性、蜡析出曲线、凝点、流变性分析及微观显微观察,从沥青质缔合状态与蜡结晶层面分析了超临界CO2处理对乙烯 醋酸乙烯共聚物(EVA)降凝剂添加到长庆原油作用效果的影响。结果表明,超临界CO2处理加剂原油相比未处理加剂原油具有更好的低温流动性能。超临界CO2处理会增加未加剂原油体系极性,增强沥青质缔合程度,使低温下蜡晶形貌更细小,恶化原油低温流动性,而超临界CO2处理后添加EVA降凝剂却使得蜡晶形貌向更加紧密的团簇转化。由于超临界CO2处理有利于EVA降凝剂进一步改善蜡晶形貌,故超临界CO2处理可以促进EVA降凝剂对长庆原油低温流动性的改善效果。     

Correlations Between the Pour Point/Gel Point and the Amount of Precipitated Wax for Waxy Crudes

The amount of precipitated wax is one of the key factors that governs the flow properties of waxy crudes. Experimental results of 24 crudes have shown that approximately 2 wt% precipitated wax is sufficient to cause a virgin waxy crude gelling. Accordingly, a correlation between the pour point and the temperature at which 2 wt% of wax has precipitated out from a crude oil; i.e., T_c(2 wt%), and a correlation between the gel point and T_c(2 wt%) have been developed. The proposed correlation of the pour point is in accordance with the correlation developed by Letoffe et al. (1995) on the basis of 14 crudes from eight countries. The development of the gel point correlation and further verification of the pour point correlation indicate that there is a relationship between the gelling of virgin waxy crudes and the amount of precipitated wax. According to these correlations and the amount of precipitated wax, which can be determined only with a little sample by thermodynamic models or Differential Scanning Calorimetry (DSC) experiment, the gel point and pour point of virgin waxy crude can be predicted even if the oil sample is very limited. Heat treatment and chemical treatment can greatly improve flow behavior of waxy crudes, and more precipitated wax is present when the beneficiated (thermally beneficiated or PPD-beneficiated) crude oils gel. Experimental results showed that approximately two or three times the amount of precipitated wax presents at the gelling temperature when the oils were in their beneficiated (thermally beneficiated or PPD-beneficiated) conditions.     

热处理对添加防蜡剂长庆原油流动性及蜡沉积特性的影响研究

基于流变性测试和蜡沉积实验研究了热处理温度对添加EVA/PAMSQ复合防蜡剂的长庆原油的流动性和蜡沉积特性的影响。研究发现加剂原油依然具有热处理效果,50℃热处理条件下加剂原油的流动性改进效果较差,随着热处理温度升高至60、70和80℃,加剂原油的流动特性(如凝点、黏度、小振幅振荡剪切特性)显著改善。80℃热处理条件下,加剂原油的凝点已低于0℃,表明热处理与EVA/PAMSQ复合防蜡剂具有良好的协同效果。同时,随着热处理温度的升高,加剂原油的蜡沉积速率逐渐降低,但蜡沉积物的含蜡量逐渐升高,这可能不利于蜡沉积物的剥离。蜡沉积物呈现出非均质结构,表层蜡沉积物为凝油状,底层蜡沉积物具有比表层蜡沉积物更高的析蜡点和屈服强度。