Inter-well scale natural fracture geometry and permeability variations in low-deformation carbonate rocks

Bisdom, Kevin; Bertotti, Giovanni; Bezerra, Francisco H.R.

doi:10.1016/j.jsg.2017.02.011

Cited by 39 publications

(23 citation statements)

References 78 publications

(114 reference statements)

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“…With regard to rocks of di erent types of lithology, their permeability coe cient (K) variation curves with stress ε are given in Figure 7. e permeability of four kinds of rocks slightly decreases with the increase in stress at the very beginning (at the stage of initial crack closure) or has no obvious change (initial cracks not developed) [29,30]. It increases slightly as the load increases before reaching the peak intensity.…”

Section: Resultsmentioning

confidence: 94%

The Assessment and Evolution of Water‐Conducting Rules under the Influence of Mining‐Induced Stress

Feng

et al. 2018

Advances in Civil Engineering

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It is important to study the mechanism of water inrush on a seam floor by exploring the rules of permeability variations during rock deformation on the seam floor and in the course of fracturing as well as their responses to characteristics of the macromechanical environment such as mine ground pressure, engineering geology, and fluid mechanics. First, through the analysis of bearing pressure changes in the process of exploiting the working face, a mechanical model for the seam floor above the confined water is established. Based on the graphic data-processing software Mathcad, the computational process and methods for assessing the vertical, horizontal, and shear stresses are provided together with the corresponding variation curve of the rock stratum 5 m below the floor, covering the entire process from a position 120 m away from the working face to a position 280 m behind it. Second, the permeability coefficients of different lithologies are measured in the laboratory. For rock stratum 5 m below the floor, the corresponding external loading path is set up according to its actual stress. The actual dynamic stress environment of the rocks is simulated, and their permeability characteristics are studied. In addition, based on data fitting, the permeability coefficient variations in the mining process are determined for a rock stratum 5 m below the floor. Finally, in accordance with the permeability variation law of the floor of the working face, the seam floor is divided into six areas, namely, the compression and expansion zone, the bed separation and expansion zone, the pressure relief zone, the compression zone, the stable recovery zone, and the stability zone. Thus, the water-resisting performance of the floor can be expressed more objectively.

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Section: Resultsmentioning

confidence: 94%

The Assessment and Evolution of Water‐Conducting Rules under the Influence of Mining‐Induced Stress

Feng

et al. 2018

Advances in Civil Engineering

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“…To conduct field mapping, great efforts were often devoted to search sites with good quality exposures to keep them to a large extent free of vegetation (Odling 1997;Odling et al 1999;Belayneh and Cosgrove 2004). However, in some geological sites, it can be very difficult to avoid the groundcover effects, because embryophytes can form vegetation on the Earth's surface over different length scales, making the mapped outcrop containing unknown gap zones (Ghosh and Daemen 1993;Rawnsley et al 1998;Gillespie et al 2001;Bisdom et al 2017). Especially for aerial photograph-based mapping, small-scale fractures can be easily hidden by forests (Lei and Wang 2016).…”

Section: Discussionmentioning

confidence: 99%

“…Figure 1 Examples showing the landscape coverage effects on mapping fracture network outcrops from photographs: a joint trace map from a photograph of a bench face (Ghosh and Daemen 1993), b line drawings of joints in an area on the edges of the Bristol Channel Basin (Rawnsley et al 1998), c digitised fracture network using aerial photography in the Jandaíra Formation (Bisdom et al 2017), and d aerial photograph and mapped fractures in the same area in Cappanawalla (Gillespie et al 2001) where n(l, L)dl gives the number of fractures with sizes belonging to the interval [l, l ? dl] (dl ( l) in an elementary volume of characteristic size L, a is the power law length exponent, a is the density term, and l min and l max are the smallest and largest fracture sizes.…”

Section: Statistical Model Of Fracture Networkmentioning

confidence: 99%

“…This may result in some biases in the measurement of fracture network geometries, such as an exaggeration of clustering behaviour, an underestimation of fracture density, and superficial truncation of large fractures (Lei and Wang 2016). Figure 1 shows a few examples of fracture patterns reported in the literature, in which the landscape coverage effects seem not trivial (Ghosh and Daemen 1993;Rawnsley et al 1998;Gillespie et al 2001;Bisdom et al 2017).…”

Section: Introductionmentioning

confidence: 99%

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Influence of Landscape Coverage on Measuring Spatial and Length Properties of Rock Fracture Networks: Insights from Numerical Simulation

Cao

Lei

2018

Pure Appl. Geophys.

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Abstract-Natural fractures are ubiquitous in the Earth's crust and often deeply buried in the subsurface. Due to the difficulty in accessing to their three-dimensional structures, the study of fracture network geometry is usually achieved by sampling two-dimensional (2D) exposures at the Earth's surface through outcrop mapping or aerial photograph techniques. However, the measurement results can be considerably affected by the coverage of forests and other plant species over the exposed fracture patterns. We quantitatively study such effects using numerical simulation. We consider the scenario of nominally isotropic natural fracture systems and represent them using 2D discrete fracture network models governed by fractal and length scaling parameters. The groundcover is modelled as random patches superimposing onto the 2D fracture patterns. The effects of localisation and total coverage of landscape patches are further investigated. The fractal dimension and length exponent of the covered fracture networks are measured and compared with those of the original non-covered patterns. The results show that the measured length exponent increases with the reduced localisation and increased coverage of landscape patches, which is more evident for networks dominated by very large fractures (i.e. small underlying length exponent). However, the landscape coverage seems to have a minor impact on the fractal dimension measurement. The research findings of this paper have important implications for field survey and statistical analysis of geological systems.

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“…Moreover, UAV setups permit the application of multispectral imaging and other tools for data collection (e.g., thermal sensors). However, the application of UAV-based techniques to the investigation of fractured aquifers (DeBell et al 2016;Bisdom et al 2017a;Massaro et al 2018) is still a relatively unexplored field compared to other geological applications (Giordan et al 2020).…”

Section: Introductionmentioning

confidence: 99%

Integration of photogrammetry from unmanned aerial vehicles, field measurements and discrete fracture network modeling to understand groundwater flow in remote settings: test and comparison with geochemical markers in an Alpine catchment

Binda¹,

Pozzi²,

Spanu³

et al. 2021

Hydrogeol J

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Fast and cost-effective techniques for hydrogeological modeling are of broad interest for water resources exploitation, especially in remote settings, where hydrogeological measurements are difficult to perform. Unmanned aerial vehicles (UAV)-based techniques are potentially useful for these aims, but their application is still limited. In this study, a field-based approach and UAV-based approach are integrated for the computation of a discrete fracture network model of a fractured aquifer in the Central Alps. Then, calculated directions of the hydraulic conductivity components were compared with a geostatistical analysis of geochemical markers from sampled spring waters, to infer a conceptual model of groundwater flow. The comparison of field-based and UAV-based fracture measurements confirmed a good matching for fracture orientations and recognized a more reliable estimation of fracture dimensions for the UAV-based dataset. Nonetheless, an important variable for hydrogeological modeling—fracture aperture—is not measurable using UAV, as this requires field measurements. The calculated directions of the main conductivities fit well with the analyzed geochemical markers, indicating the presence of two partially separated fractured aquifers and describing their possible groundwater flow paths. The adopted integrated approach confirms UAV-based measurements as a potential tool for characterization of fracture sets as the input for hydrogeological modeling and for a fast and effective surveying tool, reducing time and cost for other following measurements.

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Inter-well scale natural fracture geometry and permeability variations in low-deformation carbonate rocks

Cited by 39 publications

References 78 publications

The Assessment and Evolution of Water‐Conducting Rules under the Influence of Mining‐Induced Stress

The Assessment and Evolution of Water‐Conducting Rules under the Influence of Mining‐Induced Stress

Influence of Landscape Coverage on Measuring Spatial and Length Properties of Rock Fracture Networks: Insights from Numerical Simulation

Integration of photogrammetry from unmanned aerial vehicles, field measurements and discrete fracture network modeling to understand groundwater flow in remote settings: test and comparison with geochemical markers in an Alpine catchment

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