Arabian Journal of Geosciences Pub Date : 2023-03-16 , DOI: 10.1007/s12517-023-11314-3 Ali Mahmoud , Rahul Gajbhiye , Jun Li , Jack Dvorkin , Syed Rizwanullah Hussaini , Hani Salman AlMukainah
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Understanding the petrophysical properties of reservoir rocks is crucial for hydrocarbon exploration and production. The evolution of digital rock physics (DRP) in recent years has led to vital improvements in core characterization and in high-quality special core analysis (SCAL) measurements. DRP can estimate petrophysical properties in sandstone reservoirs using digital models. For heterogeneous carbonates, it is difficult to capture the full range of the pore structure with a single imaging technique due to pore sizes ranging from nm to cm. This study aims to accurately characterize sandstone and carbonate core plugs permeability using DRP. In addition, effective and total porosity was evaluated for establishing trends with a variable range of permeability. Six representative sandstone outcrop samples were chosen for this study to cover different lithology types, and five carbonate samples from Middle Eastern reservoirs were selected. A multi-scale imaging approach using an X-ray computer tomography CT, a 3D X-ray microtomographic CT, an X-ray diffraction (XRD), and a quantitative evaluation of minerals using scanning electron microscopy (QEMSCAN) were performed on the samples. After laboratory measurements, the samples were scanned using an X-ray CT with a 1-mm resolution to evaluate the heterogeneity of the rock structure. A sub-plug was then extracted for high-resolution scanning at a resolution of 4 µm using an X-ray micro-CT. At this scale, pore connectivity can be revealed from top to bottom. The 3D images were analyzed using the PerGeos software. The connected porosity of the segmented pores was obtained using the PerGeos software, and flow characteristics were simulated with the Lattice-Boltzmann method (LBM) and compared with laboratory measurements. The porosity obtained using the PerGeos software was comparable to laboratory measurements. The permeability obtained using LBM was in good agreement with experimental results. For high-permeability samples, the difference between total and effective porosity was observed to be lower than in low-permeability samples. This study forms the basis for accurate porosity–permeability evaluation using LBM and conventional laboratory measurements. It also shows the importance and application of DRP for flow characterization of reservoir rock. The accurate estimation of flow characteristics contributes to a better understanding of reservoir evaluation and management and mastering the usage of DRP as a non-destructive tool to evaluate rock characteristics and compare them to standard laboratory practices.
中文翻译:
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用于评估储层流动特性的数字岩石物理学 (DRP) 工作流程
了解储层岩石的岩石物理特性对于油气勘探和生产至关重要。近年来,数字岩石物理学 (DRP) 的发展已导致岩心表征和高质量特殊岩心分析 (SCAL) 测量的重大改进。DRP 可以使用数字模型估算砂岩储层的岩石物理特性。对于非均相碳酸盐,由于孔径从 nm 到 cm 不等,因此很难使用单一成像技术捕获整个范围的孔隙结构。本研究旨在使用 DRP 准确描述砂岩和碳酸盐岩心塞的渗透性。此外,还评估了有效孔隙率和总孔隙率,以建立具有可变渗透率范围的趋势。本研究选择了六个具有代表性的砂岩露头样品以涵盖不同的岩性类型,并选择了五个来自中东储层的碳酸盐岩样品。使用 X 射线计算机断层扫描 CT、3D X 射线显微断层扫描 CT、X 射线衍射 (XRD) 的多尺度成像方法,以及使用扫描电子显微镜 (QEMSCAN) 对样品进行的矿物定量评估. 在实验室测量后,使用分辨率为 1 毫米的 X 射线 CT 对样本进行扫描,以评估岩石结构的异质性。然后使用 X 射线显微 CT 以 4 µm 的分辨率提取子插头进行高分辨率扫描。在这个尺度上,可以从上到下揭示孔隙连通性。使用 PerGeos 软件分析 3D 图像。利用 PerGeos 软件获得分段孔隙的连通孔隙率,并利用格子-玻尔兹曼方法 (LBM) 模拟流动特性,并与实验室测量值进行比较。使用 PerGeos 软件获得的孔隙率与实验室测量结果相当。使用 LBM 获得的渗透率与实验结果非常吻合。对于高渗透率样品,观察到总孔隙率和有效孔隙率之间的差异低于低渗透率样品。这项研究为使用 LBM 和常规实验室测量进行准确的孔隙度-渗透率评估奠定了基础。也说明了DRP在储层岩石流动表征中的重要性和应用。