Polydispersity of heavy organics in crude oils and their role in oil well fouling
Polydispersity of heavy organics in crude oils and their role in oil well fouling
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DOI：
10.1016/j.petrol.2006.10.013
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发表时间：
2007-09-01
影响因子：
--
通讯作者：
Shariaty-Niassar, Mojtaba
中科院分区：
文献类型：
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作者：
Mansoori, G. Ali;Vazquez, Dynora;Shariaty-Niassar, Mojtaba
本文利用原油重质有机组分和固体沉积物的多分散数据，探讨了油井沉积的原因。几年来，由于大量有机物沉积，该研究的油田经历了停产和产量下降。采用了机械清洗和定期芳香洗涤等措施来维持生产水平；然而，与这些程序有关的费用非常高。采用SARA法将样品分离成四个不同的组分，即饱和烃、芳烃、树脂和沥青质。采用正戊烷、正庚烷和正戊烷作为沉淀溶剂，测定了原油样品的总沥青质含量。通过凝胶渗透色谱（GPC）进一步表征了各组分的多分散性和分子量。用气相色谱-质谱分析了固体沉积物中金刚石的存在。该技术已应用于从某油田采集的各种原油样品。研究结果为研究造成沉积现象的各种重有机质之间的相互作用提供了有用的信息。来自不同井的固体样品的组成相似，表明这些原油经历了相似的沉积机制。这些研究表明，该油田不同井产出的原油在性质上非常相似。部分原油样品中的沥青质表现出较强的自缔合倾向；它们也带来了最多的降水。虽然已证实原油中存在金刚石类和烷基取代金刚石类，但未发现它们在矿床中存在的证据。这里提出的多分散性分析程序提供了对沉淀物种的整体行为以及这些物种之间相互作用的良好理解。结果表明，这些原油中所含的重质有机物大部分会产生沉淀，而沥青质是导致沉淀絮凝的主要原因，可能导致油井淤积和堵塞。(C) 2007 Elsevier B.V.版权所有
In this report, the polydisperse data of heavy organic fractions of crude oil and solid deposit were produced to investigate the causes of deposition in oil wells. The oilfields of the study have experienced, for several years, shutdowns and decrease in the production ratios due to heavy organics deposition. Several measures such as mechanical cleaning and periodic aromatic washes have been adopted to maintain the production level; nevertheless the costs associated with these procedures are very high. The SARA method was employed to separate the samples into four distinct fractions, namely Saturates, Aromatics, Resins and Asphaltenes. The total asphaltene content of the crude oil samples was determined using n-pentane, n-heptane, and n-nonuse as the precipitating solvents. Polydispersity and molecular weight of each fraction have been further characterized by Gel Permeation Chromatography (GPC). The presence of diamondoids in the solid deposits was also investigated by GC-MS. This technique has been carried out on various crude oil samples collected from an oil field.The results provided useful information on the interaction between the various heavy organic species responsible for the deposition phenomena. Solid samples from different wells resulted in similar composition concluding that these crude oils undergo similar deposition mechanisms. These studies showed that the crude oils produced from different wells in this oilfield are very similar in nature. The asphaltenes contained in some of the crude oil samples displayed a rather strong tendency to self-associate; they also render the highest amounts of precipitation. While diamondoids and alkyl-substituted diamondoids were confirmed to be present in the crude oils produced no evidence was found of their occurrence in the deposits.The polydispersity, analysis procedure presented here provides a good understanding of the overall behavior of the species that precipitate and also of the interactions among these species. It is concluded that while most of the heavy organics contained in these crude oils may produce precipitates, asphaltene is the major cause of flocculation of the precipitates, which may result in deposition and plugging of oil-producing wells. (C) 2007 Elsevier B.V. All rights reserved.