哈法亚油田原油沥青质沉积趋势预测及分析

为了研究哈法亚油田沥青质的沉积趋势,对哈法亚油田三种不同油藏原油进行四组分分离,利用胶体体系稳定性定量计算方法预测了沥青质的沉积趋势,并采用元素分析、红外光谱(FTIR)、凝胶渗透色谱(GPC)、核磁共振(1H-NMR)等分析手段对其沥青质分子结构进行了表征,探索了沥青质分子结构与沉积趋势的内在联系。研究结果表明：哈法亚油田原油沥青质有沉积的趋势,且样品A胶体不稳定指数较大,其沥青质较容易沉积。三种沥青质的结构参数存在差异,分子量、芳香度和芳香缩合度从样品A沥青质、样品B沥青质、样品C沥青质依次减少,而氢碳比(H/C比)依次增大。沥青质聚集体的稳定性与沥青质分子结构特征密切相关,H/C比值较低以及分子量、芳香度、芳香缩合度较高的样品A沥青质具有更大的稳定能,其沥青质沉淀的可能性也较大。

Prediction and Analysis of Asphaltene Deposition Trend in Halfaya Oilfield

In order to study the trend of asphaltene deposition in Halfaya Oilfield, three kinds of crude oils were separated into four components, the trend of asphaltene deposition was predicted by colloidal instability index, and the molecular structure of the asphaltenes were characterized by elemental analysis, Fourier Transform Infrared Spectrometer(FTIR), Gel Permeation Chromatography (GPC) and Nuclear Magnetic Resonance Spectroscopy (1H-NMR). The results indicate that asphaltenes have a tendency to deposit in Halfaya Oilfield. And the greater colloidal instability index, the more prone to asphaltene deposition. The structural parameters of the asphaltenes are different, asphaltene of the sample A contains more aromatic nucleus and more branched alkanes, asphaltene of sample B has the lowest number of branched alkanes, asphaltene of sample C has the lowest number of aromatic nucleus. The molecular weight, aromaticity and aromatic condensation degree decrease in turn, and hydrogen-to-carbon ratio increases. The stability of aggregates is closely related to the molecular structure of asphaltene, the stability of the aggregates increases with lower hydrogen-to-carbon ratio, higher molecular weight, higher aromaticity, and higher aromatic condensation degree, in addition, a greater stability of the aggregates produces a greater tendency toward precipitation.