CAT scans diagnose rock permeability

3RD INTERNATIONAL CONFERENCE ON EARTH SCIENCE, MINERAL, AND ENERGY

The presence of groundwater flow in an underground mine is influenced by the aquifer fractures interconnected to rocks. Permeability testing method is commonly used to estimate the amount of groundwater. However, permeability tests, both in the laboratory and in-situ, are limited and expensive. Meanwhile, rock quality designation (RQD) which is a standard parameter for determining rock mass classification, can be measured rapidly. Therefore, the this study aims to obtain a mathematical permeability value approach with RQD. The RQD values were compared to the previously established mathematical permeability of Snow theory. Lithological samples (40 samples from 6 drill holes) were collected from PT Cibaliung Sumberdaya's underground mining concession, located in Pandeglang Regency, Banten Province, Indonesia. The results showed that the coefficient of determination (R2) for the overall lithology from the comparison between permeability and RQD was 0.42. Meanwhile, the R2 for Porphyritic Andesite (ANDS), Andesitic Flow (PAND), Vein Breccia (VNBR), Vein Crustiform-Colloform (VEIN), Vein Quartz Stocwork (FTVN), and Andesitic Breccia (BRAN) were 0.7046, 0.56, 0.845, 0.651, 0.7403, and 0.726, respectively. In conclusion, the permeability of mathematical calculations with RQD could not be used as a standard method because RQD does not include aperture discontinuity information, where the aperture is the main factor affecting rock mass permeability. Nevertheless, RQD measurement may provide preliminary permeability description.

Journal of Geophysical Research: Solid Earth, 2017

A comprehensive worldwide permeability data set has been compiled consisting of 29,000 in situ permeabilities from 221 publications and reports and delineating the permeability distribution in crystalline rocks into depths of 2000 meters below ground surface (mbgs). We analyze the influence of technical factors (measurement method, scale effects, preferential sampling, and hydraulic anisotropy) and geological factors (lithology, current stress regime, current seismotectonic activity, and long‐term tectonogeological history) on the permeability distribution with depth, by using regression analysis and k‐means clustering. The influence of preferential sampling and hydraulic anisotropy are negligible. A scale dependency is observed based on calculated rock test volumes equaling 0.6 orders of magnitude of permeability change per order of magnitude of rock volume tested. Based on the entire data set, permeability decreases as log(k) = −1.5 × log(z) − 16.3 with permeability k (m2) and pos...

Physical Review E, 2005

We computationally investigate cross-property correlations linking fluid permeability to conductive properties in sedimentary rock for a number of pore size parameters based on three-dimensional digitized rock images. In particular, we focus on correlations based on the pore volume-to-surface-area ratio ͑V p / S͒, a critical channel diameter ᐉ c associated with mercury porosimetry measurements, length scales associated with the nuclear magnetic resonance relaxation time T 2 , as well as the mean survival time ͗͘. Differences between the length scales are discussed. All these correlations yield good agreement with our simulations, but permeability estimates based on the critical diameter ᐉ c are found to be most reliable.

International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 1991

Rock-formation permeability is one important flow parameter associated with subsurface production and injection. Its importance is reflected by the number of available techniques (well-log evaluation, core measurements, and well testing) typically used to estimate it. The literature is full of comparisons and correlations of permeability from these sources. Too often these comparisons and correlations are used to make important conclusions without proper regard to the interrelationships among them. Permeability estimates by individual techniques within the various permeability sources can vary with the state of rock (in-situ environment), fluid saturation distribution, flow direction, and the scale of the medium under investigation. This paper reviews the commercially available permeability-estimation techniques and discusses the impor" tant factors that illustrate their interrelationships. Knowledge of appropriate interrelationships among the various techniques allows meaningful permeability comparisons and correlations. Usefulness of the interrelationships is demonstrated with field data. Also, the interrelationship concepts presented are a cornerstone for reservoir flow characterization.

2004

Five relevant digital image analysis parameters for fluid flow are obtained from 2-D image analysis of carbonate rocks: 2-D image porosity, amount of pores, pore shape, total perimeter per area and dominant pore size range. Micro-porosity leads to low permeable, highly porous rocks. 2-D image porosity represents the macro-porosity because the resolution subtracts the small pores from the porosity. Compared to the total porosity, it improves the prediction of permeability by an order of magnitude in the high porosity range. Pore shape factor γ reduces the uncertainty in permeability prediction to 2 orders of magnitude. Pore shape factor analysis is restricted to samples with more than 4000 pores/cm 2 . CT scans of plugs reveals that the pore shape factor γ is a relatively constant measure of the pore shape (+/-0.2) throughout the sample plug. The larger the average pore size, the higher the velocity at a given porosity. The average pore size can be quantified by the upper limit of the dominant pore size range.

International Journal of Rock Mechanics and Mining Sciences, 2014

Porosity and specific surface are two prominent factors in describing the hydraulic properties of porous media. Determination of these two important parameters leads to identify the capability of porous media to conduct the fluids. In the present study, a new relationship between porosity and specific surface of sandstones has been developed. Micro-CT data from 10 types of sandstones has been utilized in order to present a porosity-specific surface correlation. This correlation also contains the average grain radius of each rock obtained by image processing algorithms. Finally, the correlation is tested on the provided data to evaluate its precision. The simplicity and applicability of the presented relationship can be attended to modify the Carman-Kozeny equation for sandstones.

Petrophysical properties of rocks were measured, and their relationships are discussed in this paper. Based on permeability and mercury intrusion porosimetry methods, porosity, and pore size distribution were determined. Furthermore, bulk and particle densities of rocks were determined. The morphology of the porous medium has been approached by mercury porosimetry gives an appearance of the pore distribution of the material. Permeability and porosity are in close relation, and it could be assumed that its relationship is linear, i.e., with increasing porosity, permeability increases as well. This relationship is influenced by other rock properties, such as the amount of open and closed pores within the rock sample, size, and distribution of pores. From this point of view, it is necessary to study these physical properties of rocks as well, because this enables an overall analysis of rocks and its possible use for geotechnical engineering.

1] What is the relationship between the visual attributes of a rock sample and its permeability, and how might such information be used in aquifer/reservoir characterization? We investigated these questions by way of three meter-scale blocks of rock, two sandstones, and one volcanic tuff. Each rock exhibits visual and permeability patterns that differ in geometry, intensity, and scale. Using a gas minipermeameter, hundreds to thousands of permeability values were collected on grids at centimeter-scale resolution from each block face and compared to the digital visual image of the same face. We found no significant direct correlation between the permeability measurements and any objective textural measure drawn from the corresponding digital images, despite the obvious resemblance of the permeability maps and visual images. Hypothesizing that the human eye relies on spatial correlation to synthesize information, we calculated and compared semivariograms for both the maps and the images. Semivariogram shape, anisotropy ratio, and principal axes orientation were consistent for the maps and images of each rock but different between rocks. To explore this similarity further, we compared discrete features appearing in map/image pairs, using a difference of Gaussian edge filter to segment (i.e., delineate) the spatial features. The filter consistently colocated visually sharp features, such as sedimentological bounding surfaces, in both the map and the image. Additionally, cumulative distribution functions characterizing the size, shape, and orientation of the segmented features were statistically indistinguishable between a permeability map and its corresponding visual image but statistically different between rocks. These results suggest that it may not always be possible to use visual images (photographs or scans) of outcrops to directly map permeability, even with a training set of punctual permeability data. In particular, defining such relations may be difficult where the scales of analysis and/or intensity of heterogeneity are limited (e.g., within a given facies) as is the case here. Where direct mapping is not possible, these results suggest that visual images can still be used to delineate spatial permeability patterns, especially to locate boundaries where sharp permeability contrasts occur. Other surrogate measurements of permeability, in particular the various geophysical methods, may exhibit similar behavior.

Routledge, 2023

The Routledge Intermediate Persian Course, second edition, is an intermediate level Persian textbook written specifically for English-speaking university students that incorporates the guidelines of the American Council of Teaching Foreign Languages and those of the Common European Framework of Reference in its tasks and activities. The diversity of the texts in this textbook helps to familiarize students with a range of literary genres and provides them with the necessary building blocks to continue reading on their own. One of the distinctive features of this book is its content-based and task-based approach to learning the language; all the material provided has been carefully selected to support and enhance a student-centred class environment. In addition, all the texts are real texts and excerpts extracted from books published in Iran. As with The Routledge Introductory Persian Course , all the texts in this volume are available online in the form of audio files. These texts are recorded by native speakers and available for instructors and students to download freely at www.routledge.com/9781032319728. The Routledge Intermediate Persian Course: Farsi Shirin Ast, Book Two, second edition, follows on where the first textbook ends and is ideal for all intermediate learners of Persian in their second year of study.

Sources et modèles des historiens anciens, 3, 2024

This book chapter is based on an article published in Portuguese in the Brazilian journal Clássica in 2019. Its first version was delivered at the conference “A Ilíada de Homero e sua recepção na Antiguidade e Modernidade”, held at the University of São Paulo in September of 2018. It analyzes the death of the characters Panthea and Abradatas in Xenophon’s Cyropaedia, within the broader context of how the theme of war is presented in the work. We suggest that the identifcation of Panthea and Abradatas with Andromache and Hektor aims to introduce the questioning of the positive representation of war in Xenophon’s narrative, as well as of the conduct of its hero, who ascends to the position of leader of the greatest empire hitherto known through violent conflict. https://ausoniuseditions.u-bordeaux-montaigne.fr/fr/scripta-antiqua/4335-sources-et-modeles-des-historiens-anciens-3.html