PREDICTING THE TIMING AND CHARACTERISTICS OF PETROLEUM FORMATION USING TAR MATS AND PETROLEUM ASPHALTENES: A CASE STUDY FROM THE NORTHERN NORTH SEA

The Northern Viking Graben area in the Norwegian North Sea was studied in order to investigate the petroleum formation characteristics of the Upper Jurassic Draupne Formation. In this area, the organofacies of the Draupne Formation, and consequently its petroleum generation characteristics, show significant variations. These variations represent a major risk, particularly in the context of basin modelling studies. Therefore, tar‐mat asphaltenes, oil asphaltenes and source‐rock samples from this area were studied in order to evaluate the use of migrated asphaltenes from petroleum reservoirs and tar mats in basin modelling. The samples were studied using bulk kinetic analysis, open‐system pyrolysis‐gas chromatography and elemental analyses, and the results were integrated into a basin modelling study. The results from these different sample materials were compared both to each other and to natural petroleum, in order to assess their significance for future petroleum exploration activities. We show that in cumulative petroleum systems, the transformation characteristics of the asphaltenes incorporate those of the individual source rock intervals which have contributed to the relevant reservoir system. Thus, the petroleum formation window predicted by the use of asphaltene kinetics is broad, and covers the majority of the formation windows predicted from the individual source rock samples. In addition, the molecular characteristics of asphaltene‐derived hydrocarbons show that compositional characteristics, such as aromaticity, correspond more closely to natural oils than to the respective source‐rock products. Our results confirm that the heterogeneous nature of the Draupne Formation results in a significantly broader petroleum formation window than is conventionally assumed. We propose that oil and tar‐mat asphaltenes from related reservoirs represent macromolecules which account for this heterogeneity in the source rock, since they represent mixtures of charges from the different organofacies. One conclusion is that the use of oil and tar‐mat asphaltenes in kinetic studies and compositional predictions may significantly improve definitions of petroleum formation characteristics in basin modelling.     

Investigation on the flocculation of asphaltenes and the colloidal stability of the crude oil fraction (> 210°C)

Several problems are encountered with asphaltenes during the exploitation, transportation, storage and treatment of crude oil. The purpose of the present work was to study the behaviour of the crude oil fraction (<210°C) by varying the temperature and doping with some hydrocarbons including solid paraffin and aromatic concentrate. The effect of flooding water was investigated. A preliminary characterization study on asphaltenes removed from the crude oil using two different solvents was performed. The state of the oil was determined by the stability factor which indicates the susceptibility of asphaltenes to agglomerate or to disperse in the continuous phase.     

Effect of Resins on Asphaltene Self‐Association and Solubility

In previous studies, asphaltenes and resins have been treated as two distinct fractions of a crude oil. The asphaltenes were assumed to be the only self‐associating fraction. However, there is evidence that resins also participate in this self‐association. In this study, molar masses of mixtures of asphaltenes and resins were measured with vapour pressure osmometry. Precipitation from the same mixtures dispersed in solutions of toluene and pentane were also measured. The data were modelled with previously developed self‐association and precipitation models. Model results with asphaltenes and resins characterized as a single distribution and as individual components are compared. The data and the modelling suggest that asphaltenes and resins are better characterized as a single distribution of self‐associating components.     

Application of microbial enhanced oil recovery technology in water‐based bitumen extraction from weathered oil sands

When using the water‐based extraction processes (WBEPs) to recover bitumen from the weathered oil sands, very low bitumen recovery arisen from the poor liberation of bitumen from sand grains is always obtained. Application of microbial enhanced oil recovery (MEOR) technology in WBEPs to solve the poor processability of the weathered ore was proposed. It was found that processability of the microbial‐treated weathered ore was greatly improved. The improved processability was attributed to the biosurfactants production in the culture solution, alteration of the solids wettability, degradation of the asphaltene component, and the decrease of the bitumen viscosity, which collectively contributed to the bitumen liberation from the surface of sand grains. Although it still has many issues to be solved for an industrial application of the MEOR technology in oil sands separation, it is believed that the findings in this work promote the solution to the poor processability of the weathered ore. © 2014 American Institute of Chemical Engineers AIChE J, 60: 2985–2993, 2014     

油砂沥青质对油砂沥青中甲苯残留的影响

利用热重质谱联用仪（TG-MS）分析了三种油砂沥青（印尼油砂沥青、伊朗油砂沥青、加拿大油砂沥青）中的甲苯残留以及油砂沥青质含量对油砂沥青中甲苯残留的影响,并在此基础上,进一步研究了油砂沥青质中的甲苯残留。结果发现,不同油砂沥青中甲苯残留量存在一定差异,其中印尼油砂沥青中的甲苯残留量最多。进一步对沥青质质量分数分别为10%、19%、30%的油砂沥青样品进行热重质谱实验,发现随着油砂沥青中沥青质含量的增加,甲苯的残留量会成倍增加。以加拿大油砂沥青质为例,研究了油砂沥青质对溶剂残留的影响,发现油砂沥青质具有对甲苯分子的夹带能力,导致甲苯分子在超过自身沸点40℃以上才能从沥青质中分离出来。油砂沥青中其他组分的存在也会加剧沥青质对甲苯的夹带作用。此外,研究还发现,在350~650℃时,油砂沥青质可以热解产生甲苯,而且油砂沥青中的沥青质含量越高,热解生成的甲苯越多。     

剂油比对煤焦油沥青质加氢过程的影响

以中低温煤焦油沥青质为原料,采用NiMoW/γ-Al_2O_3商业催化剂,在反应温度380℃、反应压力8 MPa和反应时间1.5 h条件下,分别在不同剂油质量比(1∶25、1∶20、1∶15、1∶10)条件下进行加氢实验,通过采用元素分析、FT-IR、XRD、~1H-NMR和XPS等分析表征手段,考察不同剂油质量比对中低温煤焦油沥青质加氢转化过程的影响。结果表明,随着剂油质量比的增加,沥青质转化率提高,加氢产物分布也发生大幅变化,沥青质和芳香分轻质化转化为饱和分。但随着剂油质量比的进一步提高,同时也发生了更多的裂化反应和缩合反应,剂油质量比在合适范围能够很好地起到加氢轻质化且抑制结焦的效果。     

石油沥青质的化学和物理─Ⅰ石油沥青质的定义和分离

石油沥青质是最重要的石油组分之一，它在石油的勘探、开发、储运、加工及重质石油产品利用方面有着重要作用．本文论述了石油沥青质的含义及分布沥青质的各种方法，详细讨论了使用溶剂分离沥青质的理论基础和各种影响因素。     

离子液体-有机溶剂复合技术处理含油污泥的研究

采用离子液体辅助溶剂萃取法处理胜利油田的含油污泥，回收原油，考察了不同溶剂、剂油比、温度、反应时间、离心机转速等条件对油和沥青质脱附效率的影响。结果表明：最佳的实验条件为在正庚烷+离子液体[Emim][BF4]溶剂体系中，剂油比50/3，温度50 ℃，反应时间20 min，离心机转速2 000 r/min；在此条件下，含油污泥中油的回收率高达90.5%，沥青质的回收率为83.1%；正庚烷和离子液体可以回收重复使用，正庚烷的一次和二次回收率分别为89.2%和74.2%；离子液体几乎没有损失，一次和二次回收率分别高达98.6%和95.4%；使用二次回收的正庚烷和离子液体为溶剂时油和沥青质的回收率分别达到85.1%和78.4%。在此基础上，探讨了含油污泥脱附过程的作用机理。离子液体-有机溶剂复合技术显著提高了油泥萃取的油回收率，对油泥的无害化和资源化工业生产具有重要的参考价值。     

沥青质分子聚集体的聚集内因

运用量子力学、分子动力学等方法,研究沥青质分子聚集体形成过程的分子构型变化、能量变化以及电子分布情况。结果表明：沥青质分子形成聚集体过程中形变能很小,沥青质分子发生形变不是沥青质聚集体形成的决定因素,但为沥青质分子聚集进而形成聚集体提供基础,沥青质分子具有很强的本征聚集活性;沥青质分子间相互作用能很大,是沥青质分子聚集体形成的决定因素,其中,属于分子间固有属性的范德华力及泡利排斥作用之和相对较小,与沥青质分子结构特征相关的π π相互作用及氢键作用之和很大,表明由沥青质分子的大芳环体系和多杂原子的结构特征引起的π π相互作用及氢键作用是导致形成沥青质分子聚集体的主要原因;在所研究体系中,金属卟啉分子与含吡啶氮的沥青质分子通过π π相互作用而非轴向配位作用形成聚集体。