Asphaltene deposition in oil reservoirs during acid stimulation, natural depletion, and CO₂ injection may cause intense formation damage and reduced productivity. Gaining a better understanding of the asphaltene deposition mechanisms and their influence on the reservoir permeability reduction will contribute to the prevention of reservoir damage and the optimization of development schemes. Although numerous models and experiments have been applied to simulate the asphaltene deposition process and evaluate the reservoir permeability loss, few analyses have been performed on natural samples from oil reservoirs undergoing asphaltene deposition. Moreover, permeability reduction simulation due to asphaltene deposition has not yet been performed in three-dimensional (3D) microscale pore systems. In this work, sandstone samples were collected from natural oil reservoirs with asphaltene deposition and analyzed by both X-ray tomography and fluorescence microscopy to identify the asphaltene. A Navier–Stokes simulator and pore network model are used to study the 3D pore spaces and to calculate the permeabilities and pore radius distributions. Ideal asphaltene deposition models are applied in the 3D pore spaces to simulate the influences of surface adsorption and pore blockage on the permeability reduction. By comparing the calculation results of the ideal models and natural samples, we found that the asphaltene deposition is a coupled effect of the surface adsorption and the pore blockage, which causes a weaker permeability loss than that from the ideal single factor models.

中文翻译：

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油藏中沥青质沉积的优先选择和渗透率降低机制：X射线显微断层照相术与荧光显微镜相结合的证据

酸刺激，自然消耗和CO ₂期间沥青质在油藏中的沉积注水可能会严重破坏地层并降低生产率。更好地了解沥青质沉积机理及其对降低储层渗透率的影响，将有助于防止储层破坏和优化开发方案。尽管已经应用了许多模型和实验来模拟沥青质沉积过程并评估储层渗透率损失，但是对来自经历沥青质沉积的油藏的天然样品进行的分析却很少。此外，尚未在三维（3D）微型孔隙系统中执行由于沥青质沉积而导致的渗透率降低模拟。在这项工作中，从具有沥青质沉积的天然油藏中收集砂岩样品，并通过X射线断层扫描和荧光显微镜进行分析以鉴定沥青质。使用Navier–Stokes模拟器和孔网络模型研究3D孔空间并计算渗透率和孔半径分布。在3D孔隙空间中应用理想的沥青质沉积模型，以模拟表面吸附和孔隙阻塞对渗透率降低的影响。通过比较理想模型和天然样品的计算结果，我们发现沥青质沉积是表面吸附和孔隙堵塞的耦合效应，与理想单因素模型相比，沥青质的沉积导致了较弱的渗透率损失。使用Navier–Stokes模拟器和孔网络模型研究3D孔空间并计算渗透率和孔半径分布。在3D孔隙空间中应用理想的沥青质沉积模型，以模拟表面吸附和孔隙阻塞对渗透率降低的影响。通过比较理想模型和天然样品的计算结果，我们发现沥青质沉积是表面吸附和孔隙堵塞的耦合效应，与理想单因素模型相比，沥青质的沉积导致了较弱的渗透率损失。使用Navier–Stokes模拟器和孔网络模型研究3D孔空间并计算渗透率和孔半径分布。在3D孔隙空间中应用理想的沥青质沉积模型，以模拟表面吸附和孔隙阻塞对渗透率降低的影响。通过比较理想模型和天然样品的计算结果，我们发现沥青质沉积是表面吸附和孔隙堵塞的耦合效应，与理想单因素模型相比，沥青质的沉积导致了较弱的渗透率损失。在3D孔隙空间中应用理想的沥青质沉积模型，以模拟表面吸附和孔隙阻塞对渗透率降低的影响。通过比较理想模型和天然样品的计算结果，我们发现沥青质沉积是表面吸附和孔隙堵塞的耦合效应，与理想单因素模型相比，沥青质的沉积导致了较弱的渗透率损失。在3D孔隙空间中应用理想的沥青质沉积模型，以模拟表面吸附和孔隙阻塞对渗透率降低的影响。通过比较理想模型和天然样品的计算结果，我们发现沥青质沉积是表面吸附和孔隙堵塞的耦合效应，与理想单因素模型相比，沥青质的沉积导致了较弱的渗透率损失。