稠油中沥青质在碱水体系中乳化性能的研究

考察了我国两个稠油区(辽河和克拉玛依九区)遘选的稠油中沥青质在碱水体系中的乳化性能。结果表明，所研究的稠油中沥青质都含有乳化活性组分，它与碱液间均形成低界面张力，有利于碱水驱油。     

乳化剂对超稠油四组分乳化性能的影响

通过乳状液透光率和界面张力考察胜利油田罗家超稠油极性四组分质量分数为2％的甲苯模型油加OP乳化剂前后与地层水、碱水的乳化性能，发现乳化荆对四组分都起到了强烈的乳化促进作用。加200mg／LOP乳化荆后，四纽分模型油透光率变化由大到小的顺序是：沥青质〉芳香分〉肢质≈饱和分；与地层水的界面张力降幅由大到小的顺序是：饱和分≈胶质〉芳香分〉沥青质：与碱水的界面张力降幅由大到小的顺序是：沥青质〉饱和分≈胶质〉芳香分。0P乳化荆使W／O型乳状液转变为0／W型，提高了稠油乳化程度，便于稠油的化学乳化开采和输送。     

大港孔店原油与碱水乳化性能的研究 Ⅱ.地层水矿化度的影响

本文研究了大港油田孔店原油在不同离子强度条件下的碱水溶液中自发乳化的性能;提出了用离子强度衡量乳化能力的经验标准;探讨了一价、二价离子及地层水矿化度对碱水驱油中乳化性能的影响;提出了碱水驱油的机理。     

CO2驱替过程中沥青质沉积及其对原油采收率的影响

针对CO2驱油过程中易造成沥青质等重有机质沉积,导致原油组分发生改变,影响驱油效果这一问题,考察了不同原油沥青质含量、岩心渗透率条件下沥青质的沉积量及CO2驱油效果,研究了CO2驱替过程中沥青质沉积和原油采收率的变化规律。实验结果表明,CO2驱油过程中引起的沥青质沉积与岩心渗透率、原油初始沥青质含量直接相关;相同条件下,低渗透岩心对沥青质沉积的影响更为明显;此外,随着沥青质沉积量的增加,CO2驱的采收率降低。     

海上稠油乳化堵塞解除技术研究

针对海上稠油油井乳化堵塞问题,室内分析了胶质、沥青质含量对原油油包水乳状液的影响,通过静态实验,考察了防乳破乳体系对稠油的防乳、破乳性能和油溶性降黏体系的溶沥青质能力、降黏性能;通过动态驱油实验,考察了两种药剂的解堵降压效果和驱油效果。实验结果表明,原油中的胶质、沥青质是稠油形成油包水乳状液的天然乳化剂,且含量越多,乳液越稳定。浓度为0.5%防乳破乳体系的防乳率为83%,破乳率为89%,具有良好的防止和解除乳化堵塞的能力;浓度为5%的油溶性降黏体系的降黏率为90%,溶沥青质速率为3.20 mg/(m L·min),可快速溶解稠油中的沥青质,降低原油黏度。动态驱油实验表明,油溶性降黏体系与防乳破乳体系可降低注入压差0.8 MPa,约为原压差的30%,驱油效果表明,两种体系的加入可使其驱油效率提升5%。化学体系可有效解除稠油乳化堵塞的问题,同时还可进一步提高洗油效率,加快采收速度,提高采收率。     

克拉玛依原油中各组分的乳化性质

用沉淀法和色谱分离法将克拉玛依原油分离成沥青质，极性物和抽余油三组分，红外光谱分析表明，沥青质和极性物中存在一些含氧官能团的羧酸类或酚类以及含氮化合物，而抽余油则主要为烃类物质，因而沥青质和极性物的界面活性大于抽余油，沥青质具有较强的油包水（W／O）乳化能力，是造成克拉玛依原油W／O乳化的主要组分，极性物具有较强的水包油（O／W）乳化能力，是造成克拉玛依原油O／W乳化的主要组分，抽余油的乳化能力很弱。     

孤岛原油正庚烷和正戊烷沥青质乳化能力研究

从孤岛原油中分离出正戊烷和正庚烷沥青质，元素分析和红外光谱分析结果表明，相对分子质量较大的正庚烷沥青质，含杂原子和极性基团较多。将两种沥青质溶于甲苯配制的模型油，分别与蒸馏水、模拟地层水、0～900mg／LHPAM溶液、0～500mg／L黏土液按1：10体积比充分乳化，测定静置时水相（水包油乳状液）透光率，据以考察沥青质的乳化能力，结果表明：正庚烷沥青质的乳化能力强于正戊烷沥青质；矿化离子使沥青质的乳化能力减弱；随聚合物浓度增大，沥青质乳化能力增强；黏土在浓度小于200mg／L时使乳化能力减弱，浓度大于200mg／L时使乳化能力增强。模型油与HPAM溶液间的界面张力，在聚合物浓度100mg／L时有最小值，在500mg／L时有最大值，正庚烷沥青质模型油的界面张力随聚合物浓度的变化较剧烈。正庚烷模型油在聚合物溶液中的乳化油滴直径分布范围较正戊烷模型油窄，聚合物浓度较大时，油滴直径分布范围较宽。正庚烷沥青质模型油与黏土液闸的界面张力，在黏土液浓度增至300mg／L时略有升高，浓度继续增大时大幅升高，而正戊烷模型油的界面张力在黏土液浓度300mg／L时有最低值。图9表3参7。     

碱水驱油原油中乳化活性组分的研究

本文用综合分离分析方法对大港、胜利、玉门油田某些原油的碱驱乳化活性组分进行了探讨。研究确定有机酸是可乳化原油中的乳化活性组分,其余则尚须进一步研究,原油中的不乳化组分会影响原油-碱水乳状液的性质;在所研究的原油中,大港 YL 原油最适于碱驱。     

二氧化碳驱过程中沥青质对储层渗透率的影响

二氧化碳驱过程中的沥青质沉淀与岩心初始渗透率、孔隙度、合油饱和度以及原油初始沥青质含量等有关。为了确定二氧化碳驱中各因素导致的沥青质沉淀以及对储层渗透率产生的影响,利用自行设计的岩心驱替实验设备,模拟油藏的二氧化碳驱过程,有针对性地研究了各影响因素与渗透率变化的关系,并根据实验结果进一步回归出各因素与渗透率变化的计算公式。将模型实验值与计算值对比发现,该渗透率变化模型计算结果均与实测结果较接近,两者的平均误差为9.6％。     

胜利孤东原油中酸性组分的分离,分析及界面活性

用溶剂萃取法从胜利孤东原油中萃取、浓缩出含有机酸的活性组分，用柱色谱分离成窄馏分并进行了波谱鉴定。考察了胜利孤东原油及萃取出酸性活性组分的剩余油与碱水溶液的乳化性质和界面张力性质。结果表明，萃余油失去了原油所具有的与碱水间的良好乳化性质和低界面张力性质，但与复合驱油体系间仍能产生明显的乳化作用     

原油沥青质絮凝初始点的测定——以渤海绥中36-1油田稠油为例

沥青质在原油中的稳定性主要取决于原油对沥青质的溶解能力。当溶解能力下降到某一临界值后 ,沥青质就会从原油中絮凝析出 ,该临界值即为沥青质絮凝初始点。采用透光率法、粘度法和显微镜法对常压下渤海绥中 3 6 1油田稠油沥青质的絮凝初始点进行了测定。结果表明 ,粘度法和显微镜法测定结果比较准确、合理 ,而透光率法因受原油色深和分光光度计光源条件的限制而使沥青质絮凝初始点滞后 ;在给定压力下 ,温度升高会使原油沥青质絮凝初始点提前     

Study of Asphaltene Precipitation Using Refractive Index Measurement

The measurements of the refractive index of crude oils were utilized in this work to enhance the understanding of the behavior of asphaltenes in crude oil, specifically, their tendency to precipitate from crude oil. The onset of asphaltene precipitation was measured in eight crude oil samples, which were titrated with either heptane or pentane in order to induce precipitation of the asphaltenes. The refractive index of each sample was measured to find its relationship to asphaltene precipitation. The assumption that refractive index of a mixture is a linear combination of the refractive indexes of the individual components was verified. It was also found that mixtures of heptane or pentane and crude oil also followed this same behavior. However, as asphaltenes began to precipitate from the solution, the refractive index no longer followed this linear mixing rule. Careful analysis of the refractive index data for each of the crude oil samples revealed many interesting relationships between the refractive index data and the content of the different polar asphaltene fractions present. The refractive index of asphaltenes was predicted from the refractive index data of crude oils. The results suggest the possibility predicting the properties and characteristics of the asphaltenes contained in a crude oil simply by measuring the refractive index.     

Study of Asphaltene Precipitation Using Refractive Index Measurement

Abstract

The measurements of the refractive index of crude oils were utilized in this work to enhance the understanding of the behavior of asphaltenes in crude oil, specifically, their tendency to precipitate from crude oil. The onset of asphaltene precipitation was measured in eight crude oil samples, which were titrated with either heptane or pentane in order to induce precipitation of the asphaltenes. The refractive index of each sample was measured to find its relationship to asphaltene precipitation. The assumption that refractive index of a mixture is a linear combination of the refractive indexes of the individual components was verified. It was also found that mixtures of heptane or pentane and crude oil also followed this same behavior. However, as asphaltenes began to precipitate from the solution, the refractive index no longer followed this linear mixing rule. Careful analysis of the refractive index data for each of the crude oil samples revealed many interesting relationships between the refractive index data and the content of the different polar asphaltene fractions present. The refractive index of asphaltenes was predicted from the refractive index data of crude oils. The results suggest the possibility predicting the properties and characteristics of the asphaltenes contained in a crude oil simply by measuring the refractive index.     

Deasphalting of crude oils using supercritical fluids

A crude oil has four main SARA constituents: saturates, aromatics, resins, and asphaltenes. The asphaltenes in crude oil are the most complex and heavy organic compounds. The asphaltenes contain highly polar substituents and are insoluble in an excess of n-heptane (or n-pentane). The classic definition of asphaltenes is based on the solution properties of petroleum residuum in various solvents. Asphaltenes are a solubility range that is soluble in light aromatics such as benzene and toluene, but is insoluble in lighter paraffins. The particular paraffins, such as n-pentane and n-heptane, are used to precipitate asphaltenes from crude oil. The effects of four different solvents (water, carbon dioxide, propane, and ethanol) on the deasphalting process under the supercritical conditions were reviewed. Supercritical water is an excellent solvent for removing of high molecular weight organic compounds such as asphaltenes from crude oils under the supercritical conditions.     

The Solubility and Three-Dimensional Structure of Asphaltenes

The tendency of the asphaltenes to form aggregates in hydrocarbon solution is one of their most characteristic features and has tended to complicate the determination of the structure of petroleum In addition, if the composition and properties of the precipitated asphaltenes reflect those of the micelles in solution, the latter should be considered as mixed micelles. This is a reasonable assumption in view of the large quantities of soluble resins found in the precipitated solid

Empirical observations indicate that the resins play an important role in stabilizing asphaltenes in crude oil and under unfavorable solvent conditions the asphaltene species are prone to further aggregation into clusters that are unstable and precipitate from the crude oil. It is also suggested that the resins and the asphaltenes from a particular crude oil have points of structural similarity relative to the asphaltenes and resins from another crude oil. On a more localized scale, i.e. in one particular crude oil there are also structural differences within the constituents of asphaltenes and structural differences within the constituents of the resins are also anticipated

Therefore, the structure of the micelles within any one crude oil must be expected to be varied and non-homogenous. From the evidence cited herein, it follows that the potential for graphite-type stacking by the asphaltene molecules in the center of a micelle might not be as great as the potential for the micelles forming by asphaltene-resin interactions rather than by asphaltene-asphaltene interactions     

Comparisons Between Asphaltenes from the Dead and Live-Oil Samples of the Same Crude Oils

Asphaltenes precipitated from pressure-preserve bottomhole oil samples have been obtained for three oils at different pressures, using a bulk high-pressure filtration apparatus. The precipitates captured on the filter were recovered, the asphaltenes defined by the n-heptane insolubility were extracted and analyzed. These pressure-driven asphaltenes found on the filter were found to make up in the range between 50 and 100 ppm of the whole crude oil. Opening of the cell did not reveal asphaltenes retained due to wall adhesion. Size exclusion chromatography tests performed on both the live-oil-derived asphaltenes and the standard asphaltenes as precipitated by atmospheric titration on the same crude oil, revealed that the live-oil asphaltenes had apparent smaller hydrodynamic volume and narrower distributions than the standard asphaltenes for two oils. Further FTIR tests also showed large differences between standard asphaltenes and the asphaltenes obtained at high pressure filter. The latter appeared to contain more functional groups and be less saturated. Implication of these structural differences on precipitation modeling is discussed.     

热处理温度对长庆原油蜡沉积特性的影响

通过Couette蜡沉积装置及DSC热分析探究了热处理温度对长庆原油蜡沉积特性的影响,发现随着热处理温度的升高,长庆原油蜡沉积速率减缓,蜡沉积层老化速率加快;经50 ℃和60 ℃热处理的长庆原油,蜡沉积层出现了分层现象,其表层为流动性较强的凝油状蜡沉积层,底层为结构较为致密的类固态蜡沉积层;经70 ℃热处理的长庆原油,蜡沉积层极薄且致密,无分层现象,其表面无凝油状蜡沉积层。采用沥青质分散程度分析、DSC热分析及蜡晶形貌显微观察探究了其影响机理,发现随着热处理温度的升高,长庆原油沥青质分散程度增大,从而使其析蜡点降低,蜡晶团聚性增强,原油低温流动性得以改善,进而对其蜡沉积特性产生了显著影响。     

Interfacial and Structural Properties of Different Natural Surfactants Extracted From Venezuelan Junin Extra Heavy Crude Oil

Abstract

In this work, acids, asphaltenes, maltenes, and acid-free asphaltenes were isolated from Venezuelan Junin extra heavy crude oil, and their interfacial properties studied using the pendant drop method. This study led to the conclusion that the acids present in the crude, which have molecular weights of about 400 Da and are present in higher concentrations in asphaltenes, account for the decrease in the interfacial tension. In other words, asphaltenes act as molecular traps for acids. Furthermore, it was possible to confirm with simpler methods that substances adsorbed at the water–crude oil interface have low molecular weights.     

稠油和油砂中沥青质等重质组分的轻度氧化降解

稠油和油砂是广泛存在的重要资源，沥青质等重质组分的存在是难以直接开发利用这些资源的关键因素。移动稠油和油砂中重质组分的轻度氧化降解问题进行了实验研究，氧化降解体系为NaIO4/NaH2PO4和30%H2O2/CH3COOH。实验结果，稠油中沥青质的降解率达到45%以上，并且沥青质降解后主要向胶质组分转化，这非常有利于增加稠油体系的稳定性；油砂经降解处理后，与空白实验相比，油砂中的重质组分得到化学降解改造，可抽提的总有机质含量明显提高。氧化降解处理可以改善稠油、油砂等重质油的理化性质，可望在稠油油藏的开发利用方面得到应用。     

Comparisons Between Asphaltenes from the Dead and Live-Oil Samples of the Same Crude Oils

Abstract

Asphaltenes precipitated from pressure-preserve bottomhole oil samples have been obtained for three oils at different pressures, using a bulk high-pressure filtration apparatus. The precipitates captured on the filter were recovered, the asphaltenes defined by the n-heptane insolubility were extracted and analyzed. These pressure-driven asphaltenes found on the filter were found to make up in the range between 50 and 100 ppm of the whole crude oil. Opening of the cell did not reveal asphaltenes retained due to wall adhesion. Size exclusion chromatography tests performed on both the live-oil-derived asphaltenes and the standard asphaltenes as precipitated by atmospheric titration on the same crude oil, revealed that the live-oil asphaltenes had apparent smaller hydrodynamic volume and narrower distributions than the standard asphaltenes for two oils. Further FTIR tests also showed large differences between standard asphaltenes and the asphaltenes obtained at high pressure filter. The latter appeared to contain more functional groups and be less saturated. Implication of these structural differences on precipitation modeling is discussed.