Multi-scale X-ray tomography analysis of carbonate porosity

Hébert, V.; Garing, Charlotte; Luquot, Linda; Pézard, Philippe; Gouze, Philippe

doi:10.1144/sp406.12

Cited by 33 publications

(22 citation statements)

References 45 publications

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“…However, more than 50% of the world's remaining oil reserves are located in carbonate reservoirs (27), and carbonate aquifers supply water wholly or partially to one quarter of the global population (28). Carbonates rocks can have complex multiscale pore structures, which render the application of X-ray μCT more challenging because of the need to select a representative sample that is small enough to achieve high resolutions on μCT images but that also captures the essential heterogeneities of the pore structure (29,30).…”

mentioning

confidence: 99%

Droplet fragmentation: 3D imaging of a previously unidentified pore-scale process during multiphase flow in porous media

Pak

Butler

Geiger

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

150

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Using X-ray computed microtomography, we have visualized and quantified the in situ structure of a trapped nonwetting phase (oil) in a highly heterogeneous carbonate rock after injecting a wetting phase (brine) at low and high capillary numbers. We imaged the process of capillary desaturation in 3D and demonstrated its impacts on the trapped nonwetting phase cluster size distribution. We have identified a previously unidentified pore-scale event during capillary desaturation. This pore-scale event, described as droplet fragmentation of the nonwetting phase, occurs in larger pores. It increases volumetric production of the nonwetting phase after capillary trapping and enlarges the fluid−fluid interface, which can enhance mass transfer between the phases. Droplet fragmentation therefore has implications for a range of multiphase flow processes in natural and engineered porous media with complex heterogeneous pore spaces.droplet fragmentation | X-ray computed microtomography | pore-scale imaging | heterogeneous porous media | carbonate rock M ultiphase fluid displacement processes in porous media are important for a broad range of natural and engineering applications such as transport of nonaqueous phase liquid contaminants in aquifers, oil and gas production from hydrocarbon reservoirs, subsurface CO 2 storage, or gas transport in fuel cells. Herein, capillary trapping is a fundamental mechanism that causes immobilization of a portion of the resident nonwetting phase when it is displaced by an invading wetting phase. As a result, production of the nonwetting phase is always less than 100%.The pore-scale physics of capillary trapping are broadly understood, as the underlying mechanisms such as piston-like displacement, snap-off and film development have been observed in physical micromodel experiments and quantitative theories have been established for them (1-4). The conventional view considers such pore-scale processes to occur between multiple pores, i.e., they are interpore processes and the pores are defined as volumes connected by narrower pore throats. By contrast, intrapore processes, as presented in this paper, are not well established in the literature. During drainage (i.e., where a nonwetting phase displaces the wetting phase), the wetting phase can establish films in the corners of the pores, which results in its continuous production and hence low residual saturations of the wetting phase. During imbibition (i.e., where the wetting phase displaces a nonwetting phase), swelling of the corner wetting films causes snap-off of the nonwetting phase, which results in capillary trapping of the nonwetting phase. The trapped nonwetting phase exists as disconnected ganglia within the pore network. Numerical pore network models have been developed to include these porelevel mechanisms with the aim of predicting the macroscopic flow properties of porous materials such as the structure of the phase distributions, residual saturation, relative permeability functions, and capillary pressure curves. Some of these mod...

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mentioning

confidence: 99%

Droplet fragmentation: 3D imaging of a previously unidentified pore-scale process during multiphase flow in porous media

Pak

Butler

Geiger

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

150

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“…Hebert et al (2014) demonstrate that porosity-permeability relationships that have been identified in carbonates using X-ray CT are non-unique and depend on the resolution of the X-ray CT scanner as well as the sample size. Furthermore, they demonstrate how variability in connectivity at fine scales may be obscured by connectivity measurements at larger scales.…”

Section: Selected Advancesmentioning

confidence: 87%

“…In particular, the amount of microporosity and the way that micro-and macroporosity are connected in carbonates appears to impact capillary pressure and relative permeability curves (Jiang et al 2013a, b). It is now possible to quantitatively combine pore-scale modelling studies, such as those of Prodanović et al (2014) or Jiang et al (2013a, b), with multiscale X-ray CT imaging of carbonates, as represented by Hebert et al (2014). By analogy to probabilistic model concepts developed in hydrology for single-phase flow, the quantitative insights from pore-scale studies can also be used to develop probabilistic models for multiphase flow that link the variability in porescale physics to the Darcy scale.…”

Section: Selected Advancesmentioning

confidence: 99%

Fundamental controls on fluid flow in carbonates: current workflows to emerging technologies

Agar

Geiger

2014

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The introduction reviews topics relevant to the fundamental controls on fluid flow in carbonate reservoirs and to the prediction of reservoir performance. The review provides research and industry contexts for papers in this volume only. A discussion of global context and frameworks emphasizes the value yet to be captured from compare and contrast studies. Multidisciplinary efforts highlight the importance of greater integration of sedimentology, diagenesis and structural geology. Developments in analytical and experimental methods, stimulated by advances in the materials sciences, support new insights into fundamental (pore-scale) processes in carbonate rocks. Subsurface imaging methods relevant to the delineation of heterogeneities in carbonates highlight techniques that serve to decrease the gap between seismically resolvable features and well-scale measurements. Methods to fuse geological information across scales are advancing through multiscale integration and proxies. A surge in computational power over the last two decades has been accompanied by developments in computational methods and algorithms. Developments related to visualization and data interaction support stronger geoscience-engineering collaborations. High-resolution and real-time monitoring of the subsurface are driving novel sensing capabilities and growing interest in data mining and analytics. Together, these offer an exciting opportunity to learn more about the fundamental fluid-flow processes in carbonate reservoirs at the interwell scale.

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“…In 2014, Ma et al [217] proposed a multiscale digital core-reconstruction method for shale gas rocks. Hebert et al [218] employed a multiscale method to evaluate the porosity of carbonate rocks. In 2015, Yang et al [219] proposed a method for combining smallscale digital cores that is equivalent to converting the resulting 3D digital cores into larger-scale 3D digital cores.…”

Section: D Slicementioning

confidence: 99%

Challenges and Prospects of Digital Core-Reconstruction Research

et al. 2019

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The simulation of various rock properties based on three-dimensional digital cores plays an increasingly important role in oil and gas exploration and development. The accuracy of 3D digital core reconstruction is important for determining rock properties. In this paper, existing 3D digital core-reconstruction methods are divided into two categories: 3D digital cores based on physical experiments and 3D digital core stochastic reconstructions based on two-dimensional (2D) slices. Additionally, 2D slice-based digital core stochastic reconstruction techniques are classified into four types: a stochastic reconstruction method based on 2D slice mathematical-feature statistical constraints, a stochastic reconstruction method based on statistical constraints that are related to 2D slice morphological characteristics, a physics process-based stochastic reconstruction method, and a hybrid stochastic reconstruction method. The progress related to these various stochastic reconstruction methods, the characteristics of constructed 3D digital cores, and the potential of these methods are analysed and discussed in detail. Finally, reasonable prospects are presented based on the current state of this research area. Currently, studies on digital core reconstruction, especially for the 3D digital core stochastic reconstruction method based on 2D slices, are still very rough, and much room for improvement remains. In particular, we emphasize the importance of evaluating functions, multiscale 3D digital cores, multicomponent 3D digital cores, and disciplinary intersection methods in the 3D construction of digital cores. These four directions should provide focus, alongside challenges, for this research area in the future. This review provides important insights into 3D digital core reconstruction.

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Multi-scale X-ray tomography analysis of carbonate porosity

Cited by 33 publications

References 45 publications

Droplet fragmentation: 3D imaging of a previously unidentified pore-scale process during multiphase flow in porous media

Droplet fragmentation: 3D imaging of a previously unidentified pore-scale process during multiphase flow in porous media

Fundamental controls on fluid flow in carbonates: current workflows to emerging technologies

Challenges and Prospects of Digital Core-Reconstruction Research

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