Asphaltene destabilization in the presence of an aqueous phase: The effects of salinity, ion type, and contact time
Asphaltene destabilization in the presence of an aqueous phase: The effects of salinity, ion type, and contact time
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DOI：
10.1016/j.petrol.2021.109757
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发表时间：
2021-12-07
影响因子：
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通讯作者：
Ayatollahi, Shahab
中科院分区：
文献类型：
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作者：
Mokhtari, Rasoul;Hosseini, Ali;Ayatollahi, Shahab
油藏注水过程中可能的流体-流体相互作用之一是注入盐水盐度对沥青质失稳的影响，这一点仍有争议。如果沥青质沉淀是由油藏和地面设施中的盐度变化引起的，这可能对低盐度注水项目的经济性产生巨大影响。因此，本研究的目的是调查的影响，盐水盐度的沥青质沉淀量和管理的不稳定机制。沥青质沉淀的直接测量，沿着与光学显微镜图像和离子色谱（IC）分析，表明沥青质沉淀机制是依赖于盐水盐度。在高矿化度条件下，沥青质与离子的结合是沥青质聚集体的主要成核机制，并可能促进沥青质沉淀。在低矿化度下，由于盐-油界面的极性，沥青质被吸附到盐-油界面上，这也可能破坏沥青质在油体中的稳定性。在所研究的所有盐水中，对于原油与地层水接触的情况观察到最高量的沥青质沉淀。根据IC结果，硫酸根和镁是在沥青质附聚物结构中发挥核心作用的最活跃离子。原油组成中环烷酸的存在会影响沥青质的沉淀量。
One of the possible fluid-fluid interactions during water-flooding in oil reservoirs, that is still debated, is the effect of injected brine salinity on asphaltene destabilization. If asphaltene precipitation is induced by salinity changes in the oil reservoirs and surface facilities, this could have a massive impact on the economy of a low salinity water-flooding project. Therefore, this study aims to investigate the effect of brine salinity on the amount of asphaltene precipitation and the governing destabilization mechanisms. Direct asphaltene precipitation measurements, along with the analyses of optical microscopy images and ion chromatography (IC), indicate that the asphaltene precipitation mechanism is dependent on brine salinity. At a high brine salinity, ions play the primary role as possible nuclei for asphaltene aggregates and might promote asphaltene precipitation through asphaltene-ions bonding. While at low salinity, the polarity of the brine-oil interface causes the asphaltenes to be adsorbed toward the brine-oil interface, and this also might disrupt the stability of asphaltenes in the oil bulk. Of all the brines investigated, the highest amount of asphaltene precipitation was observed for the case in which crude oil was in contact with formation water. Based on the IC results, sulfate and magnesium are the most active ions to play the role of the nucleus in the structure of asphaltene agglomerates. Results also showed that the presence of Naphthenic Acids (NAs) in crude oil composition can affect the amount of asphaltene precipitation.