使用磁共振成像(MRI)技术研究多孔介质中的流体流动特性:确定毛管压力和相对渗透率。
Fluid flow characteristics in porous media using Magnetic Resonance Imaging (MRI) technique: Determining the capillary pressure and relative permeability.
作者信息
Mohammadi Khashayar, Esfandiarian Ali, Taheri-Shakib Jaber
机构信息
Fatigue and Stress Analysis Laboratory (FATSlab), Department of Mechanical & Mechatronics Engineering, University of Waterloo, Waterloo, ON N2L 3G1, Canada.
Department of Petroleum Engineering, Fars Science and Research Branch, Islamic Azad University, Marvdasht, Fars, Iran; Department of Petroleum Engineering, Marvdasht Branch, Islamic Azad University, Marvdasht, Fars, Iran.
出版信息
Adv Colloid Interface Sci. 2025 Jun 16;343:103582. doi: 10.1016/j.cis.2025.103582.
Conventional laboratory methods for measuring and determining fluid flow parameters often involve complexities and simplifications that can lead to inaccuracies. These limitations hinder a comprehensive understanding of fluid flow behavior in reservoirs. This study reviews the use of Magnetic Resonance Imaging (MRI) as a non-invasive technique to investigate key parameters governing fluid flow in porous media, such as capillary pressure and relative permeability. MRI enables direct measurement of capillary pressure without the need for traditional, routine procedures. By analyzing MRI intensity, saturation levels can be determined across different sections of the rock based on hydrogen content. Additionally, MRI allows for the evaluation of porous structures and pore-throat geometry. This technique is particularly effective and efficient for analyzing cores with high capillary pressures and fully water-saturated conditions. It also facilitates the observation of fingering and channeling mechanisms during water or gas injection processes. Relative permeability can be assessed using MRI by analyzing signal intensity and water/oil saturation at specific points within the porous medium. Furthermore, MRI provides insights into breakthrough events for water and gas, as well as the morphology of the displacing front during fluid injection. Despite its advantages, the MRI technique has certain limitations. These include constraints related to spatial resolution and the performance of MRI radiofrequency coils for long core samples. Additionally, its accuracy diminishes in cases of high water saturation at the outlet face of the core or when fluid flow rates are low. The MRI technique based on hydrogen offers significant advantages over traditional methods for measuring capillary pressure and relative permeability, as it directly determines fluid saturation within porous media. This method is highly accurate and efficient, even for cores with higher capillary pressures or fully water-saturated conditions, without requiring the extraction of water from the core. Additionally, MRI enables precise characterization of pore-throat structures, heterogeneities in reservoir rock pore systems, and the mobility ratios of water and oil, which are critical factors in understanding phenomena like fingering and channeling during CO capillary trapping. Relative permeability can be derived from MRI analysis by examining saturation levels and fluid flow velocities. The displacement processes of fluids (gas or liquid) within porous media are determined using hydrogen-based MRI signals, as fluids lacking hydrogen produce negligible signal responses. This capability allows for detailed observation of the structure and behavior of injected fluids, including the displacing front at various locations in porous media. It is particularly useful in high-permeability zones where breakthrough events occur under different pressures and flow conditions. Unlike traditional methods, MRI accounts for the capillary end effect-a phenomenon that can introduce errors in evaluating oil/water saturation-by considering stationary wetting phase distribution during relative permeability measurements. This makes MRI a more reliable tool for accurately assessing fluid dynamics in porous media. However, limitations such as resolution constraints and challenges with low flow rates or high water saturation at the outlet face still exist, requiring further optimization for broader applicability. This paper highlights the potential of the MRI technique as a highly accurate, fast, and efficient method for studying fluid flow in the porous media of reservoir rocks. Its application is steadily transforming reservoir rock analysis, offering new perspectives and opportunities for laboratories and research centers in this field.
用于测量和确定流体流动参数的传统实验室方法往往涉及复杂情况和简化处理,这可能导致不准确。这些局限性阻碍了对储层中流体流动行为的全面理解。本研究回顾了磁共振成像(MRI)作为一种非侵入性技术,用于研究控制多孔介质中流体流动的关键参数,如毛管压力和相对渗透率。MRI能够直接测量毛管压力,无需传统的常规程序。通过分析MRI强度,可以根据氢含量确定岩石不同截面的饱和度水平。此外,MRI还可以评估多孔结构和孔喉几何形状。该技术对于分析具有高毛管压力和完全水饱和条件的岩心特别有效和高效。它还便于观察水或气体注入过程中的指进和窜流机制。通过分析多孔介质内特定点的信号强度和水/油饱和度,可以使用MRI评估相对渗透率。此外,MRI还能深入了解水和气体的突破事件,以及流体注入过程中驱替前缘的形态。尽管MRI技术具有优势,但也存在某些局限性。这些包括与空间分辨率以及长岩心样品的MRI射频线圈性能相关的限制。此外,在岩心出口面水饱和度高或流体流速低的情况下,其准确性会降低。基于氢的MRI技术在测量毛管压力和相对渗透率方面比传统方法具有显著优势,因为它可以直接确定多孔介质内的流体饱和度。即使对于具有较高毛管压力或完全水饱和条件的岩心,该方法也高度准确和高效,无需从岩心中提取水。此外,MRI能够精确表征孔喉结构、储层岩石孔隙系统中的非均质性以及水和油的流度比,这些是理解二氧化碳捕集过程中诸如指进和窜流等现象的关键因素。通过检查饱和度水平和流体流速,可以从MRI分析中得出相对渗透率。多孔介质内流体(气体或液体)的驱替过程是使用基于氢的MRI信号确定的,因为缺乏氢的流体产生的信号响应可忽略不计。这种能力允许详细观察注入流体的结构和行为,包括多孔介质中不同位置的驱替前缘。在不同压力和流动条件下发生突破事件的高渗透区,它特别有用。与传统方法不同,MRI通过在相对渗透率测量过程中考虑静止润湿相分布,考虑了毛管末端效应——一种在评估油/水饱和度时可能引入误差的现象。这使得MRI成为准确评估多孔介质中流体动力学的更可靠工具。然而,诸如分辨率限制以及出口面低流速或高水饱和度带来的挑战等局限性仍然存在,需要进一步优化以实现更广泛的适用性。本文强调了MRI技术作为一种高精度、快速且高效的方法用于研究储层岩石多孔介质中流体流动的潜力。其应用正在稳步改变储层岩石分析,为该领域的实验室和研究中心提供新的视角和机会。