The impact of asphaltene deposition on fluid flow in sandstone
The impact of asphaltene deposition on fluid flow in sandstone
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DOI：
10.1016/j.petrol.2018.11.056
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发表时间：
2019-03
影响因子：
--
通讯作者：
M. Mehana;J. J. Abraham-J.;M. Fahes
中科院分区：
文献类型：
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作者：
M. Mehana;J. J. Abraham-J.;M. Fahes
沥青质在油藏中的沉积是影响油井和油藏产能的一个有争议的问题。尽管这一现象以前已经在几个实验室实验中被研究过，但沥青质沉积的均匀性方面通常被忽视。我们之前已经开发了一种实验工作流程，在岩心样品中创建均匀的沥青质沉积物。在这项研究中，通过渗吸、岩心驱替和相对渗透率实验，量化了这种均匀沉积对流体流动的影响。此外，实验室结果被用于现场规模的模拟，以调查沉积对现场性能的影响。结果表明，沉积后的润湿性状态发生了变化，吸水率和吸水量均有所降低。此外，检测到的绝对渗透率降低了25%。在裸露岩石上进行的岩心压降实验结果表明，裸露岩石的润湿特征发生了变化，裸露岩石变得更加混合/中湿，并随岩石中初始卤水饱和度的变化而变化。随后，在观察到剩余油饱和度的移动、油曲线的下降和水曲线的上升的情况下，相对渗透率集受到影响。将这一新数据放大到油田规模表明，如果实施注水，油井产能将损失一半以上，并将更早取得突破。
Asphaltene deposition in oil reservoirs is a contentious issue affecting both well and reservoir productivity. Though the phenomenon has been previously studied in several laboratory experiments, the uniformity aspects of the asphaltene deposit are usually overlooked. We have previously developed an experimental workflow to create a uniform deposit of asphaltene inside the core sample. In this study, the impact of this uniform deposit on fluid flow is quantified through imbibition, corefloods and relative permeability experiments. In addition, the lab results are used in a field scale simulation to investigate the impact of deposition on field performance. The results exhibit a shift in the wettability state where a reduction in both water imbibition rate and capacity are observed after deposition. Besides, up to 25% reduction in absolute permeability is detected. Results of pressure drop experiments across the core conducted on the exposed rocks indicate a change in the wetting characteristics, with the exposed rocks becoming more mixed/intermediate wet and varying with the change in the initial brine saturation in the rock. Subsequently, the relative permeability set is affected where a shift in the oil residual saturation, a downgrade in the oil curve and an upgrade in the water curve are observed. Upscaling this new data to field scale indicated a loss of more than half of the well productivity and an earlier breakthrough if waterflooding is implemented.