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The use of acid for permeability enhancement has gained popularity in mining and oil industries to enhance the recovery rate of low-permeability formations. This study employed static acid permeability enhancement tests, flooding acid permeability enhancement tests, and micro-CT scanning to investigate the mechanism of permeability enhancement and changes in pore structure during acid...
Water transport under dynamic vehicle load is the primary causation of asphalt pavement water damage. The dynamic water breaks through the inner voids and destroys the micro-structure of asphalt mixture, and consequently degrades asphalt pavement durability. Understanding the microstructure evolution and void connecting during dynamic water load contributes to the water damage mechanism of...
The oolitic limestone reservoir of Qianjiang Formation in Jianghan Oilfield has the characteristics of shallow burial, thin layer, developed upper and lower water layers and strong heterogeneity, so it is difficult to be reformed on site. In order to optimize the transformation process and the optimal process parameters suitable for the reservoir, the core dissolution experiment and acid...
Fluid-rock interactions drive changes in porosity and permeability. This has important consequences for the flow field development in the complex porous material and thus controls the evolution of reactive transport processes. Important applications are in the vast field of reservoir rock alteration, e.g. by coupled dissolution and precipitation processes. While dissolution processes can cause...
Image segmentation techniques for processing scanning electron microscopy (SEM) images can enhance the efficiency of oil and gas field exploration. This study initiates by reviewing the limitations of traditional SEM image segmentation methods (threshold-based, boundary-based and region-based), especially the challenges in processing complex structures and high-noise images. Subsequently, the...
After imaging samples with CT or FIB-SEM, correctly and precisely detecting pores in the digital acquisition requires image segmentation. A series of steps are necessary to be able to correctly process the data. Firstly, a series of filters must be applied to prepare the data for segmentation. Then a segmentation method must be selected. Finally, each detected pore must be measured.
With...
Multiphase flow and reactive transport in porous media play a key role in various applications needed for establishing hydrogen as an alternative energy carrier. To successfully establish hydrogen, the porous media facilitating the hydrogen flow in presence of another fluid, needs to be optimized in terms of reactivity and transport properties. Two important parameters controlling reactivity...
Imaging has always played a vital role in obtaining a better understanding of porous media processes through laboratory experiments. In contrast to pore-scale imaging, extracting Darcy-scale interpretation from porous media experiments has so far not drawn equally big attention. On the other hand, various imaging techniques used in the lab often do not offer pore-scale resolution, e.g.,...
Natural porous media is generally heterogeneous and anisotropic. The structure of porous media plays a vital role and is often the source of heterogeneity and anisotropy. In a physical process such as fluid flow in porous media, a small number of major features here referred to as wide channels, are responsible for the majority of the flow. The thickness and orientation of these channels often...
The porous media community extensively utilizes digital rock images for core analysis. High-resolution digital rock images that possess sufficient quality are of great importance, but are sometimes difficult to obtain and suffer from high cost. Super-resolution (SR) approaches enhance the resolution of digital rock images, and provide improved visualization of fine features and structures,...
Gas trapping and escaping in layered geological settings widely occur. We utilized an in-situ gas injection apparatus based on high-resolution micro-CT to investigate gas invasion behaviors and deformation patterns of layered porous media systems. The system includes a reservoir and a cap layer with carefully controlled capillarity and permeability. Results show that all cases experience...
X-ray microtomography (micro-CT) provides a nondestructive way for estimating rock properties such as relative permeability. Relative permeability is computed on the fluid distributions generated on three dimensional images of the pore structure of a rock. However, it is difficult to numerically reproduce actual fluid distributions at the pore scale, particularly for a mixed-wet rock. Recent...
The Tarim Basin is well known for its high-gas production as observed in the remarkable West-to-East Gas Transmission Project. The reservoirs are mainly located deep at approximately 8000-m vertically in different types of lithologies, with tight petrophysical properties. Fluid identification is a key tool used to locate the sweet spot with high producibility for further development....
Microscopic pore structure characteristics of both reservoir and source rocks (e.g., sandstones, carbonates, and mudrocks) –pore-size distribution, pore shape, and pore connectivity – control fluid flow and chemical transport. Focusing on effective porosity, the portion of connected pore space as conductive pathways to participate in flow and transport (e ,, as an indicator of macroscopic...
Introduction
Micro-CT is a unique technology to non-destructively investigate the internal structure of samples, spanning a range from centimeter to micrometer scale. However, when it comes to material identification, the technology has some inherent limitations. The contrast observed within a micro-CT scan arises from a multitude of factors. The attenuation coefficient of a material is...
We employed X-ray Computed Tomography (CT) and Scanning Electron Microscopy-Energy Dispersive Spectroscopy (SEM-EDS), alongside a steady-state flow experiment involving calcite-contained sandstone and pre-equilibrated fluids, to study the changes occurring in the pores of sandstone during CO2 injection. In-situ pore-scale imaging showed a significant increase in average porosity, from 23% to...
Evaporation from porous media is a key phenomenon in the terrestrial environment and is linked to accumulation of solutes at or near the evaporative surface. Such accumulation eventually leads to salinization, soil degradation and weathering of building materials, topics with high economic impacts. A thorough understanding of evaporation and the associated solute accumulation requires the...
The shift from fossil fuel-based energy sources and toward more environmentally friendly, renewable alternatives highlights how important it is to properly plug and abandon oil and gas wells. Most depleted wells in the energy industry have been allocated for initial-phase abandonment, and cement has long been an appropriate material for permanently plugging these wellbores. Permanent plugging...
